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Tachibana N, Hosono K, Nomura S, Arai S, Torii K, Kurata K, Sato M, Shimakawa S, Azuma N, Ogata T, Wada Y, Okamoto N, Saitsu H, Nishina S, Hotta Y. Maternal Uniparental Isodisomy of Chromosome 4 and 8 in Patients with Retinal Dystrophy: SRD5A3-Congenital Disorders of Glycosylation and RP1-Related Retinitis Pigmentosa. Genes (Basel) 2022; 13:genes13020359. [PMID: 35205402 PMCID: PMC8872353 DOI: 10.3390/genes13020359] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 01/27/2023] Open
Abstract
Purpose: Uniparental disomy (UPD) is a rare chromosomal abnormality. We performed whole-exosome sequencing (WES) in cases of early-onset retinal dystrophy and identified two cases likely caused by UPD. Herein, we report these two cases and attempt to clarify the clinical picture of retinal dystrophies caused by UPD. Methods: WES analysis was performed for two patients and their parents, who were not consanguineous. Functional analysis was performed in cases suspected of congenital disorders of glycosylation (CDG). We obtained clinical case data and reviewed the literature. Results: In case 1, a novel c.57G>C, p.(Trp19Cys) variant in SRD5A3 was detected homozygously. Genetic analysis suggested a maternal UPD on chromosome 4, and functional analysis confirmed CDG. Clinical findings showed early-onset retinal dystrophy, intellectual disability, and epilepsy. In case 2, an Alu insertion (c.4052_4053ins328, p.[Tyr1352Alafs]) in RP1 was detected homozygously. Maternal UPD on chromosome 8 was suspected. The clinical picture was consistent with RP1-related retinitis pigmentosa. Although the clinical features of retinal dystrophy by UPD may vary, most cases present with childhood onset. Conclusions: There have been limited reports of retinal dystrophy caused by UPD, suggesting that it is rare. Genetic counseling may be encouraged in pediatric cases of retinal dystrophy.
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Affiliation(s)
- Nobutaka Tachibana
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Katsuhiro Hosono
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Shuhei Nomura
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Shinji Arai
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Kaoruko Torii
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Kentaro Kurata
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Miho Sato
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
| | - Shuichi Shimakawa
- Department of Pediatrics, Osaka Medical and Pharmaceutical University Hospital, Takatsuki 569-8686, Japan;
| | - Noriyuki Azuma
- National Center for Child Health and Development, Department of Ophthalmology and Laboratory for Visual Science, Tokyo 157-8535, Japan; (N.A.); (S.N.)
| | - Tsutomu Ogata
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (T.O.); (H.S.)
- Hamamatsu Medical Center, Department of Pediatrics, Hamamatsu 432-8580, Japan
| | - Yoshinao Wada
- Department of Molecular Medicine, Osaka Women’s and Children’s Hospital, Izumi 594-1101, Japan; (Y.W.); (N.O.)
| | - Nobuhiko Okamoto
- Department of Molecular Medicine, Osaka Women’s and Children’s Hospital, Izumi 594-1101, Japan; (Y.W.); (N.O.)
- Department of Medical Genetics, Osaka Women’s and Children’s Hospital, Izumi 594-1101, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (T.O.); (H.S.)
| | - Sachiko Nishina
- National Center for Child Health and Development, Department of Ophthalmology and Laboratory for Visual Science, Tokyo 157-8535, Japan; (N.A.); (S.N.)
| | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan; (N.T.); (K.H.); (S.N.); (S.A.); (K.T.); (K.K.); (M.S.)
- Correspondence: ; Tel.: +81-53-435-2256
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Muthusamy K, Macke EL, Klee EW, Tebben PJ, Hand JL, Hasadsri L, Marcou CA, Schimmenti LA. Congenital ichthyosis in Prader-Willi syndrome associated with maternal chromosome 15 uniparental disomy: Case report and review of autosomal recessive conditions unmasked by UPD. Am J Med Genet A 2020; 182:2442-2449. [PMID: 32815268 DOI: 10.1002/ajmg.a.61792] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 06/23/2020] [Accepted: 07/11/2020] [Indexed: 11/09/2022]
Abstract
Prader-Willi syndrome (PWS) is a prototypic genetic condition related to imprinting. Causative mechanisms include paternal 15q11-q13 deletion, maternal chromosome 15 uniparental disomy (UPD15), Prader-Willi Syndrome/Angelman Syndrome (PWS/AS) critical region imprinting defects, and complex chromosomal rearrangements. Maternal UPD15-related PWS poses risks of concomitant autosomal recessive (AR) disorders when the mother carries a pathogenic variant in one of the genes on chromosome 15 associated with autosomal recessive inherited disease. Co-occurrence of autosomal recessive conditions in the setting of UPD leads to increased complexity of the clinical phenotype, and may delay the diagnosis of PWS. We report a patient with PWS and associated congenital ichthyosis due to maternal UPD15, and a homozygous novel pathogenic variant in ceramide synthase 3 (CERS3). We also review the literature of associated disorders reported in the setting of maternal UPD15-related PWS and provide a summary of the previously described CERS3 variants. This represents the second case of autosomal recessive congenital ichthyosis (ARCI) in the setting of PWS and UPD15. There needs to be a high index of suspicion of this genetic mechanism when there is unexpected phenotype or evolution of the clinical course in a patient with PWS.
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Affiliation(s)
- Karthik Muthusamy
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota, USA
| | - Erica L Macke
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA
| | - Eric W Klee
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota, USA.,Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA
| | - Peter J Tebben
- Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Division of Pediatric Endocrinology, Mayo Clinic, Rochester, Minnesota, USA.,Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota, USA
| | - Jennifer L Hand
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota, USA.,Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Dermatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Linda Hasadsri
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Cherisse A Marcou
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota, USA.,Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Lisa A Schimmenti
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota, USA.,Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota, USA.,Department of Otorhinolaryngology, Mayo Clinic, Rochester, Minnesota, USA
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Santos JFD, Acosta AX, Scheibler GG, Pitanga PML, Alves ES, Meira JGC, Zanardo ÉA, Kulikowski LD, Lima RLLFD, Carvalho AFLD. Case of 15q26-qter deletion associated with a Prader-Willi phenotype. Eur J Med Genet 2020; 63:103955. [PMID: 32473228 DOI: 10.1016/j.ejmg.2020.103955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 05/15/2020] [Accepted: 05/16/2020] [Indexed: 11/28/2022]
Abstract
Prader-Willi syndrome (PWS) is one of the common neurogenetic disorders associated with intellectual disability. PWS involves a complex inheritance pattern and is caused by an absence of gene expression on the paternally inherited 15q11.2-q13 region, either due to deletion, maternal uniparental disomy or imprinting defect. The syndrome is characterized principally by severe neonatal hypotonia, a weak suck in infancy that is later followed by hyperphagia and obesity, developmental delay, intellectual disability and short stature. In the case of the chromosome 15q26-qter deletion syndrome or Drayer's syndrome, very few reports have been published. Its characteristics include intrauterine growth restriction, postnatal growth failure, varying degrees of intellectual disability, developmental delay, typical facial appearance and diaphragmatic hernia. The present paper describes a female patient in whom clinical findings were suggestive of PWS and deletion in the 15q26-qter region. Both karyotyping and methylation-specific polymerase chain reaction were shown to be normal. Nevertheless, fluorescence in situ hybridization showed a 15qter deletion that was later mapped by single nucleotide polymorphism (SNP)-array. The deleted genomic region involves the insulin-like growth factor-1 receptor (IGF1R) gene, which is related to short stature, developmental delay and intellectual disability. This case had various clinical characteristics in common with the cases of 15q26-qter deletionand characteristics compatible with PWS.
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Affiliation(s)
- Jéssica Fernandes Dos Santos
- Laboratory of Human Genetics and Mutagenesis, Institute of Biology, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Angelina Xavier Acosta
- Department of Medical Genetics, Edgard Santos Teaching Hospital Academic, Federal University of Bahia, Salvador, Bahia, Brazil; Pediatrics Department, School of Medicine, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Gabriela Gayer Scheibler
- Department of Medical Genetics, Edgard Santos Teaching Hospital Academic, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Paula Monique Leite Pitanga
- Laboratory of Human Genetics and Mutagenesis, Institute of Biology, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Esmeralda Santos Alves
- Laboratory of Human Genetics and Mutagenesis, Institute of Biology, Federal University of Bahia, Salvador, Bahia, Brazil; Department of Medical Genetics, Edgard Santos Teaching Hospital Academic, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Joanna Goes Castro Meira
- Department of Medical Genetics, Edgard Santos Teaching Hospital Academic, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Évelin Aline Zanardo
- Pathology Department, Cytogenomics Laboratory - LIM 03, University of São Paulo, São Paulo, Brazil
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A modified MS-PCR approach to diagnose patients with Prader-Willi and Angelman syndrome. Mol Biol Rep 2016; 43:1221-1225. [PMID: 27535666 DOI: 10.1007/s11033-016-4055-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 08/08/2016] [Indexed: 02/08/2023]
Abstract
Prader-Willi (PWS) and Angelman (AS) syndromes are clinically distinct neurodevelopmental genetic diseases with multiple phenotypic manifestations. They are one of the most common genetic syndromes caused by non-Mendelian inheritance in the form of genomic imprinting, and can be attributable to the loss of gene expression due to imprinting within the chromosomal region 15q11-q13. Clinical diagnosis of PWS and AS is challenging, and the use of molecular and cytomolecular studies is recommended to help in determining the diagnosis of these conditions. The methylation analysis is a sensible approach; however there are several techniques for this purpose, such as the methylation-sensitive polymerase chain reaction (MS-PCR). This study aims to optimize the MS-PCR assay for the diagnosis of potential PWS and AS patients using DNA modified by sodium bisulfite. We used the MS-PCR technique of PCR described by Kosaki et al. (1997) adapted with betaine. All different concentrations of betaine used to amplify the methylated and unmethylated chromosomal region 15q11-q13 on the gene SNRPN showed amplification results, which increased proportionally to the concentration of betaine. The methylation analysis is a technically robust and reproducible screening method for PWS and AS. The MS-PCR assures a faster, cheaper and more efficient method for the primary diagnosis of the SNRPN gene in cases with PWS and AS, and may detect all of the three associated genetic abnormalities: deletion, uniparental disomy or imprinting errors.
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Prader-Willi Syndrome: The Disease that Opened up Epigenomic-Based Preemptive Medicine. Diseases 2016; 4:diseases4010015. [PMID: 28933395 PMCID: PMC5456307 DOI: 10.3390/diseases4010015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 03/04/2016] [Accepted: 03/07/2016] [Indexed: 01/20/2023] Open
Abstract
Prader-Willi syndrome (PWS) is a congenital neurodevelopmental disorder caused by loss of function of paternally expressed genes on chromosome 15 due to paternal deletion of 15q11–q13, maternal uniparental disomy for chromosome 15, or an imprinting mutation. We previously developed a DNA methylation-based PCR assay to identify each of these three genetic causes of PWS. The assay enables straightforward and rapid diagnosis during infancy and therefore allows early intervention such as nutritional management, physical therapy, or growth hormone treatment to prevent PWS patients from complications such as obesity and type 2 diabetes. It is known that various environmental factors induce epigenomic changes during the perinatal period, which increase the risk of adult diseases such as type 2 diabetes and intellectual disabilities. Therefore, a similar preemptive approach as used in PWS would also be applicable to acquired disorders and would make use of environmentally-introduced “epigenomic signatures” to aid development of early intervention strategies that take advantage of “epigenomic reversibility”.
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Chen H, Zhu Z, Lu JJ, Liu S. Charging YOYO-1 on capillary wall for online DNA intercalation and integrating this approach with multiplex PCR and bare narrow capillary-hydrodynamic chromatography for online DNA analysis. Anal Chem 2015; 87:1518-22. [PMID: 25555111 PMCID: PMC4318619 DOI: 10.1021/ac504257b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
Multiplex polymerase chain reaction
(PCR) has been widely utilized
for high-throughput pathogen identification. Often, a dye is used
to intercalate the amplified DNA fragments, and identifications of
the pathogens are carried out by DNA melting curve analysis or gel
electrophoresis. Integrating DNA amplification and identification
is a logic path toward maximizing the benefit of multiplex PCR. Although
PCR and gel electrophoresis have been integrated, replenishing the
gels after each run is tedious and time-consuming. In this technical
note, we develop an approach to address this issue. We perform multiplex
PCR inside a capillary, transfer the amplified fragments to a bare
narrow capillary, and measure their lengths online using bare narrow
capillary–hydrodynamic chromatography (BaNC-HDC), a new technique
recently developed in our laboratory for free-solution DNA separation.
To intercalate the DNA with YOYO-1 (a fluorescent dye) for BaNC-HDC,
we flush the capillary column with a YOYO-1 solution; positively charged
YOYO-1 is adsorbed (or charged) onto the negatively charged capillary
wall. As DNA molecules are driven down the column for separation,
they react with the YOYO-1 stored on the capillary wall and are online-intercalated
with the dye. With a single YOYO-1 charging, the column can be used
for more than 40 runs, although the fluorescence signal intensities
of the DNA peaks decrease gradually. Although the dye-DNA intercalation
occurs during the separation, it does not affect the retention times,
separation efficiencies, or resolutions.
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Affiliation(s)
- Huang Chen
- Department of Chemistry and Biochemistry, University of Oklahoma , 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
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Abstract
"Angelman syndrome" (AS) is a neurodevelopmental disorder whose main features are intellectual disability, lack of speech, seizures, and a characteristic behavioral profile. The behavioral features of AS include a happy demeanor, easily provoked laughter, short attention span, hypermotoric behavior, mouthing of objects, sleep disturbance, and an affinity for water. Microcephaly and subtle dysmorphic features, as well as ataxia and other movement disturbances, are additional features seen in most affected individuals. AS is due to deficient expression of the ubiquitin protein ligase E3A (UBE3A) gene, which displays paternal imprinting. There are four molecular classes of AS, and some genotype-phenotype correlations have emerged. Much remains to be understood regarding how insufficiency of E6-AP, the protein product of UBE3A, results in the observed neurodevelopmental deficits. Studies of mouse models of AS have implicated UBE3A in experience-dependent synaptic remodeling.
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Affiliation(s)
- Lynne M Bird
- Department of Pediatrics, University of California, Division of Genetics, Rady Children’s Hospital, San Diego, California, USA
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Epilepsy in Prader-Willi syndrome: clinical, diagnostic and treatment aspects. World J Pediatr 2014; 10:108-13. [PMID: 24801229 DOI: 10.1007/s12519-014-0478-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/06/2014] [Indexed: 12/29/2022]
Abstract
BACKGROUND Epilepsy associated with Prader-Willi syndrome (PWS) represents an early and important complication, often not clearly reported and described in the literature. Consequently, there are controversial data about the clinical characteristics of epilepsy and electroencephalographic (EEG) abnormalities found in these patients. DATA SOURCES Based on recent original publications, we have reviewed the different types of seizures and EEG findings in PWS patients, the response to antiepileptic treatment, and the prognosis of epilepsy. RESULTS The frequency of epilepsy in PWS patients ranges from 4% to 26%. The types of seizure include generalized tonic-clonic seizures, complex partial seizures, atypical absence, staring spells, and myoclonic, tonic and hemiclonic seizures, but the most frequent type is focal epilepsy. Status epilepticus has never been reported. EEG abnormalities are not typical but variable in different patients. However, generalized and focal discharges are the most frequently reported findings. There is no evidence of relationship between the course of epilepsy and frequency, morphology and spread of EEG discharges. However, epilepsy in PWS patients is usually responsive to antiepileptic monotherapy with rapid seizure control and a good outcome. CONCLUSIONS The frequency of epilepsy is higher in PWS patients than in general populations and this complication can be a challenge for the clinicians of these patients. Prospective studies are needed to confirm the good long-term prognosis.
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Sánchez J, Fernández R, Madruga M, Bernabeu-Wittel J, Antiñolo G, Borrego S. Somatic and germ-line mosaicism of deletion 15q11.2-q13 in a mother of dyzigotic twins with Angelman syndrome. Am J Med Genet A 2013; 164A:370-6. [DOI: 10.1002/ajmg.a.36281] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 09/12/2013] [Indexed: 12/15/2022]
Affiliation(s)
- Javier Sánchez
- Department of Genetics; Reproduction and Fetal Medicine; Institute of Biomedicine of Seville (IBIS); University Hospital Virgen del Rocío; CSIC; University of Seville; Seville Spain
| | - Raquel Fernández
- Department of Genetics; Reproduction and Fetal Medicine; Institute of Biomedicine of Seville (IBIS); University Hospital Virgen del Rocío; CSIC; University of Seville; Seville Spain
- Centre of Biomedical Network Research on Rare Diseases (CIBERER); Seville Spain
| | - Marcos Madruga
- Department of Pediatrics; University Hospital Virgen del Rocío; Seville Spain
| | | | - Guillermo Antiñolo
- Department of Genetics; Reproduction and Fetal Medicine; Institute of Biomedicine of Seville (IBIS); University Hospital Virgen del Rocío; CSIC; University of Seville; Seville Spain
- Centre of Biomedical Network Research on Rare Diseases (CIBERER); Seville Spain
| | - Salud Borrego
- Department of Genetics; Reproduction and Fetal Medicine; Institute of Biomedicine of Seville (IBIS); University Hospital Virgen del Rocío; CSIC; University of Seville; Seville Spain
- Centre of Biomedical Network Research on Rare Diseases (CIBERER); Seville Spain
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Tzagkaraki E, Sofocleous C, Fryssira-Kanioura H, Dinopoulos A, Goulielmos G, Mavrou A, Kitsiou-Tzeli S, Kanavakis E, Sofia KT, Kanavakis E. Screening of UBE3A gene in patients referred for Angelman Syndrome. Eur J Paediatr Neurol 2013; 17:366-73. [PMID: 23416059 DOI: 10.1016/j.ejpn.2012.12.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 12/27/2012] [Accepted: 12/30/2012] [Indexed: 01/05/2023]
Abstract
Angelman Syndrome (AS) is a neurodevelopmental disorder characterized by severe developmental delay, speech impairment and unique behaviors including inappropriate laughter and happy disposition. AS is related to deficient maternal UBE3A gene expression caused either by chromosomal deletions, uniparental disomy, molecular defects of the imprinted 15q11-q13 critical region or by loss of function mutations in the maternally inherited UBE3A. In the present study, screening UBE3A was performed in 43 patients who were referred for AS but whom previous molecular diagnostic tests failed to provide a diagnosis. Two causative mutations--one of them novel--and four polymorphic variants one of which is also novel were revealed. Further investigation of 7 patients disclosed defects in other genes involved in clinical phenotypes mimicking AS. A typical EEG pattern and microcephaly in patients with developmental delay prompt for AS investigation while wide genetic screening should be applied to help resolution of the complex phenotypes characterized by developmental delay.
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Affiliation(s)
- Evmorfia Tzagkaraki
- Department of Medical Genetics, University of Athens School of Medicine, Choremeio Research Laboratory, Aghia Sophia Children's Hospital, Thivon and Levadeias str, 11527 Goudi, Athens, Greece.
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Chen Y, Liu YJ, Pei YF, Yang TL, Deng FY, Liu XG, Li DY, Deng HW. Copy number variations at the Prader-Willi syndrome region on chromosome 15 and associations with obesity in whites. Obesity (Silver Spring) 2011; 19:1229-34. [PMID: 21233802 PMCID: PMC4512297 DOI: 10.1038/oby.2010.323] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Obesity is a serious health problem with strong genetic determination. Copy number variation (CNV) is a common type of genomic variant associated with some complex human diseases. However, it is not clear how CNVs contribute to the etiology of obesity. In this study, we examined 1,000 unrelated US whites to search for CNVs that may predispose to obesity. We focused our analyses on the Prader-Willi syndrome (PWS) critical region (chromosome 15q11-q13), because the PWS region is a hotspot for CNV generation and obesity is one of the major clinical manifestations for chromosome abnormalities at this region. We constructed a map containing 39 CNVs at the PWS critical region with CNV occurrence rates higher than 1%. Among them, three CNVs were significantly associated with body fat mass (P < 0.05), with a higher copy number (CN) associated with an increase of 5.08-9.77 kg in body fat mass. These three CNVs are close to two known PWS genes, NDN (necdin homolog) and C15orf2 (chromosome 15 open reading frame 2), and partially overlap with another obesity gene PWRN1 (Prader-Willi region nonprotein-coding RNA 1). Interestingly, our recently published whole genome association scan study using the same sample by examining single-nucleotide polymorphisms (SNPs) did not find any significant associations at these CNV regions, suggesting the importance of examining both CNVs and SNPs for better understanding of genetic basis of obesity. Further studies are warranted to validate these CNVs and their importance to obesity.
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Affiliation(s)
- Yuan Chen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, The People’s Republic of China
| | - Yong-Jun Liu
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Yu-Fang Pei
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, The People’s Republic of China
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Tie-Lin Yang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, The People’s Republic of China
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Fei-Yan Deng
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - Xiao-Gang Liu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, The People’s Republic of China
| | - Ding-You Li
- Department of Pediatrics, Children’s Mercy Hospital, Kansas City, Missouri, USA
| | - Hong-Wen Deng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education and Institute of Molecular Genetics, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, The People’s Republic of China
- School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
- Center of System Biomedical Sciences, Shanghai University of Science and Technology, Shanghai, The People’s Republic of China
- College of Life Sciences and Engineering, Beijing Jiao Tong University, Beijing, The People’s Republic of China
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Hou A, Lin SP, Ho SY, Chen CFJ, Lin HY, Chen YJ, Huang CY, Chiu HC, Chuang CK, Chen KS. Genetic studies of Prader-Willi patients provide evidence for conservation of genomic architecture in proximal chromosome 15q. Ann Hum Genet 2011; 75:211-21. [PMID: 21198515 DOI: 10.1111/j.1469-1809.2010.00633.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Prader-Willi syndrome (PWS) is a neurogenetic disorder associated with recurrent genomic recombination involving low copy repeats (LCRs) located in the human chromosome 15q11-q13. Previous studies of PWS patients from Asia suggested that there is a higher incidence of deletion and lower incidence of maternal uniparental disomy (mUPD) compared to that of Western populations. In this report, we present genetic etiology of 28 PWS patients from Taiwan. Consistent with the genetic etiology findings from Western populations, the type II deletion appears to be the most common deletion subtype. Furthermore, the ratio of the two most common deletion subtypes and the ratio of the maternal heterodisomy to isodisomy cases observed from this study are in agreement with previous findings from Western populations. In addition, we identified and further mapped the deletion breakpoints in two patients with atypical deletions using array CGH (comparative genomic hybridization). Despite the relatively small numbers of patients in each subgroup, our findings suggest that the genomic architecture responsible for the recurrent recombination in PWS is conserved in Taiwanese of the Han Chinese heritage and Western populations, thereby predisposing chromosome 15q11-q13 to a similar risk of rearrangements.
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Affiliation(s)
- Aihua Hou
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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Kitsiou-Tzeli S, Tzetis M, Sofocleous C, Vrettou C, Xaidara A, Giannikou K, Pampanos A, Mavrou A, Kanavakis E. De novo interstitial duplication of the 15q11.2-q14 PWS/AS region of maternal origin: Clinical description, array CGH analysis, and review of the literature. Am J Med Genet A 2010; 152A:1925-32. [PMID: 20575009 DOI: 10.1002/ajmg.a.33447] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The 15q11-q13 PWS/AS critical region involves genes that are characterized by genomic imprinting. Multiple repeat elements within the region mediate rearrangements, including interstitial duplications, interstitial triplications, and supernumerary isodicentric marker chromosomes, as well as the deletions that cause Prader-Willi syndrome (PWS) and Angelman syndrome (AS). Recently, duplications of maternal origin concerning the same critical region have been implicated in autism spectrum disorders (ASD). We present a 6-month-old girl carrying a de novo duplication of maternal origin of the 15q11.2-q14 PWS/AS region (17.73 Mb in size) [46,XX,dup(15)(q11.2-q14)] detected with a high-resolution microarray-based comparative genomic hybridization (array-CGH). The patient is characterized by severe hypotonia, obesity, microstomia, long eyelashes, hirsutism, microretrognathia, short nose, severe psychomotor retardation, and multiple episodes of drug-resistant epileptic seizures, while her brain magnetic resonance imaging (MRI) documented partial corpus callosum dysplasia. In our patient the duplicated region is quite large extending beyond the Prader-Willi-Angelman critical region (PWACR), containing a number of genes that have been shown to be involved in ASD, exhibiting a severe phenotype, beyond the typical PWS/AS clinical manifestations. Reporting of similar well-characterized clinical cases with clearly delineated breakpoints of the duplicated region will clarify the contribution of specific genes to the phenotype.
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Affiliation(s)
- Sophia Kitsiou-Tzeli
- Department of Medical Genetics, Medical School, University of Athens, Athens, Greece
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Ramsden SC, Clayton-Smith J, Birch R, Buiting K. Practice guidelines for the molecular analysis of Prader-Willi and Angelman syndromes. BMC MEDICAL GENETICS 2010; 11:70. [PMID: 20459762 PMCID: PMC2877670 DOI: 10.1186/1471-2350-11-70] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 05/11/2010] [Indexed: 11/26/2022]
Abstract
Background Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are clinically distinct neurodevelopmental genetic disorders that map to 15q11-q13. The primary phenotypes are attributable to loss of expression of imprinted genes within this region which can arise by means of a number of mechanisms. The most sensitive single approach to diagnosing both PWS and AS is to study methylation patterns within 15q11-q13; however many techniques exist for this purpose. Given the diversity of techniques available, there is a need for consensus testing and reporting guidelines. Methods Testing and reporting guidelines have been drawn up and agreed in accordance with the procedures of the UK Clinical Molecular Genetics Society and the European Molecular Genetics Quality Network. Results A practical set of molecular genetic testing and reporting guidelines has been developed for these two disorders. In addition, advice is given on appropriate reporting policies, including advice on test sensitivity and recurrence risks. In considering test sensitivity, the possibility of differential diagnoses is discussed. Conclusion An agreed set of practice guidelines has been developed for the diagnostic molecular genetic testing of PWS and AS.
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Affiliation(s)
- Simon C Ramsden
- National Genetics Reference Laboratory (Manchester), Saint Mary's Hospital, Hathersage Road, Manchester M13OJH, UK.
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Clarke DJ, Boer H, Webb T. GENETIC AND BEHAVIOURAL ASPECTS OF PRADER-WILLI SYNDROME: A REVIEW WITH A TRANSLATION OF THE ORIGINAL PAPER. ACTA ACUST UNITED AC 2010. [DOI: 10.1111/j.1468-3148.1995.tb00141.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
Single nucleotide polymorphism arrays (SNP-A) have recently been widely applied as a powerful karyotyping tool in numerous translational cancer studies. SNP-A complements traditional metaphase cytogenetics with the unique ability to delineate a previously hidden chromosomal defect, copy neutral loss of heterozygosity (CN-LOH). Emerging data demonstrate that selected hematologic malignancies exhibit abundant CN-LOH, often in the setting of a normal metaphase karyotype and no previously identified clonal marker. In this review, we explore emerging biologic and clinical features of CN-LOH relevant to hematologic malignancies. In myeloid malignancies, CN-LOH has been associated with the duplication of oncogenic mutations with concomitant loss of the normal allele. Examples include JAK2, MPL, c-KIT, and FLT3. More recent investigations have focused on evaluation of candidate genes contained in common CN-LOH and deletion regions and have led to the discovery of tumor suppressor genes, including c-CBL and family members, as well as TET2. Investigations into the underlying mechanisms generating CN-LOH have great promise for elucidating general cancer mechanisms. We anticipate that further detailed characterization of CN-LOH lesions will probably facilitate our discovery of a more complete set of pathogenic molecular lesions, disease and prognosis markers, and better understanding of the initiation and progression of hematologic malignancies.
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Wattanasirichaigoon D, Promsonthi P, Chuansumrit A, Leopairut J, Yanatatsaneejit P, Rattanatanyong P, Munkongdee T, Fucharoen S, Mutirangura A. Maternal uniparental disomy of chromosome 16 resulting in hemoglobin Bart’s hydrops fetalis. Clin Genet 2008; 74:284-7. [DOI: 10.1111/j.1399-0004.2008.01046.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Webb T, Hardy CA, King M, Watkiss E, Mitchell C, Cole T. A clinical, cytogenetic and molecular study of ten probands with supernumerary inv dup (15) marker chromosomes. Clin Genet 2008. [DOI: 10.1111/j.1399-0004.1998.tb02578.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Pornthanakasem W, Kongruttanachok N, Phuangphairoj C, Suyarnsestakorn C, Sanghangthum T, Oonsiri S, Ponyeam W, Thanasupawat T, Matangkasombut O, Mutirangura A. LINE-1 methylation status of endogenous DNA double-strand breaks. Nucleic Acids Res 2008; 36:3667-75. [PMID: 18474527 PMCID: PMC2441779 DOI: 10.1093/nar/gkn261] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
DNA methylation and the repair of DNA double-strand breaks (DSBs) are important processes for maintaining genomic integrity. Although DSBs can be produced by numerous agents, they also occur spontaneously as endogenous DSBs (EDSBs). In this study, we evaluated the methylation status of EDSBs to determine if there is a connection between DNA methylation and EDSBs. We utilized interspersed repetitive sequence polymerase chain reaction (PCR), ligation-mediated PCR and combined bisulfite restriction analysis to examine the extent of EDSBs and methylation at long interspersed nuclear element-1 (LINE-1) sequences nearby EDSBs. We tested normal white blood cells and several cell lines derived from epithelial cancers and leukemias. Significant levels of EDSBs were detectable in all cell types. EDSBs were also found in both replicating and non-replicating cells. We found that EDSBs contain higher levels of methylation than the cellular genome. This hypermethylation is replication independent and the methylation was present in the genome at the location prior to the DNA DSB. The differences in methylation levels between EDSBs and the rest of the genome suggests that EDSBs are differentially processed, by production, end-modification, or repair, depending on the DNA methylation status.
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Affiliation(s)
- Wichai Pornthanakasem
- Center of Excellence in Molecular Genetics of Cancer and Human Diseases, Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
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20
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Torrado M, Araoz V, Baialardo E, Abraldes K, Mazza C, Krochik G, Ozuna B, Leske V, Caino S, Fano V, Chertkoff L. Clinical-etiologic correlation in children with Prader-Willi syndrome (PWS): An interdisciplinary study. Am J Med Genet A 2007; 143A:460-8. [PMID: 17163531 DOI: 10.1002/ajmg.a.31520] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Prader-Willi syndrome (PWS) is a multisystemic disorder caused by the loss of expression of paternally transcribed genes within chromosome 15q11-q13. Most cases are due to paternal deletion of this region; the remaining cases result from maternal uniparental disomy (UPD) and imprinting defects. To better understand the phenotypic variability of PWS, a genotype-phenotype correlation study was performed in 91 children with PWS. Patients were diagnosed by Southern Blot Methylation assay and genetic subtypes were established using FISH and microsatellite analyses. Fifty-nine subjects with deletion (31/28 males/females; mean age 3.86 years), 30 with UPD (14/16 males/females; mean age 3.89 years) and 2 girls with a presumed imprinting defect (mean age 0.43 yrs) were identified. For correlation purposes patients were grouped as "deleted" and "non-deleted." An increased maternal age was found in the UPD group. Four of Holm's criteria were more frequently present in the deleted group: need for special feeding techniques, sleep disturbance, hypopigmentation, and speech articulation defects. Concerning cognitive assessments, only 9.52% of subjects with deletion had Full-Scale IQ (FSIQ) > or =70, while 61.53% of subjects without deletion had FSIQ > or =70. Similar results were found in behavioral measures. Sleep disorders and carbohydrate metabolism were systematically assessed. Polysomnoghaphic studies revealed a higher frequency of central events with desaturations > or =10% in the deleted group (P = 0.020). In summary, the phenotype was significantly different between both groups in certain parameters related to the CNS. These results might be related to the differences in brain gene expression of the genetic subtypes.
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Affiliation(s)
- Maria Torrado
- Hospital de Pediatría Prof. Dr. Juan P. Garrahan - Genética, Buenos Aires, Argentina.
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21
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Promkan M, Teingtat S, Stheinkijkarnchai A, Wasant P, Patmasiriwat P. Highest accuracy of combined consensus clinical criteria and SNRPN gene molecular markers in diagnosis of Prader-Willi syndrome in Thai patients. Clin Chem Lab Med 2007; 45:972-80. [PMID: 17867985 DOI: 10.1515/cclm.2007.271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Prader-Willi Syndrome (PWS) is a complex human genetic disease arising from a loss of paternal allele expression of imprinting genes on chromosome 15q11-q13. Normally the CpG islands at this site are heavily methylated in the maternal allele, but unmethylated in the paternal allele and therefore activated in gene expression. only the methylated allele should present in pws patients when methylation-specific pcr (msp) is analyzed. METHODS This paper reports an analysis of PWS in Thai patients using consensus diagnostic criteria based on a combination of clinical data, basic G-banding and fluorescence in situ hybridization (FISH) cytogenetics, PCR-based methylation assay, and bisulfite sequencing of the CpG islands of SNRPN to confirm 15q deletion or the methylation pattern of the SNRPN promoter and exon 1. Lack of complete clinical reports or inadequacy of the minimum laboratory support required had made it difficult to diagnose PWS, Angelman syndrome and other microdeletion disorders. RESULTS Accuracy of 100% was obtained for diagnosis of the PWS study patients using the minimum requirements necessary. A total of 20 patients were diagnosed as PWS based on clinical criteria and the scoring tool for PWS, and the same approach was applied to four separate patients with some unmatched criteria but phenotypic similarity to PWS. Findings showed that 70% of those clinically diagnosed as PWS patients (14/20) had a deletion at 15q11-q13 according to FISH, while all 20 patients showed MSP positive of SNRPN gene. Six cases (30%) without a paternal deletion were confirmed to have maternal uniparental disomy (mUPD) of PWS by MSP and methylation sequencing approaches. Noteworthy, two of the six cases with mUPD were 3.5 year-old twins. None of the five cases with scores lower than the reported consensus criteria showed positive G-band, FISH or MSP results. CONCLUSIONS We demonstrate here the high power of combining clinical findings, FISH and MSP in definitive diagnosis of PWS and in distinguishing between the two major different types of molecular mechanisms. No false positives or false negatives were observed in our analysis.
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Affiliation(s)
- Moltira Promkan
- Department of Clinical Microscopy, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
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22
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Martínez F, León AM, Monfort S, Oltra S, Roselló M, Orellana C. Robust, Easy, and Dose-Sensitive Methylation Test for the Diagnosis of Prader–Willi and Angelman Syndromes. ACTA ACUST UNITED AC 2006; 10:174-7. [PMID: 17020468 DOI: 10.1089/gte.2006.10.174] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We present a new method for differential diagnosis of Prader-Willi (PWS) and Angelman syndromes (AS) that requires only a small amount of DNA including that obtained from amniocentesis specimens. This method not only proved to be robust and rapid, but, most importantly, it can be dosage sensitive, supplying additional information useful for genetic counselling. After methylation-dependent digestion of DNA with HpaII or McrBC, exon 1 of the SNRPN gene is amplified together with a sequence in the CpG island of the H19 gene. Given the similarities in sequence composition and methylation status between the amplified sequences, their co-amplification under semiquantitative conditions allows an easy discrimination between single dosage (present in deletions or chromosomal translocations) and a double-dosage state (uniparental disomy or imprinting error), when the appropriate controls are included. The method we have developed in combination with standard cytogenetic studies and segregation analysis of microsatellite markers offers a rapid and easy procedure to resolve most suspected cases of PWS and AS, and consequently to provide accurate genetic counselling.
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Affiliation(s)
- Francisco Martínez
- Unidad de Genética y Diagnóstico Prenatal, Hospital Universitario La Fe, Valencia, Spain.
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23
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Valente KD, Fridman C, Varela MC, Koiffmann CP, Andrade JQ, Grossmann RM, Kok F, Marques-Dias MJ. Angelman syndrome: uniparental paternal disomy 15 determines mild epilepsy, but has no influence on EEG patterns. Epilepsy Res 2005; 67:163-8. [PMID: 16226874 DOI: 10.1016/j.eplepsyres.2005.09.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Revised: 08/16/2005] [Accepted: 09/07/2005] [Indexed: 10/25/2022]
Abstract
The authors describe the electroclinical phenotype of four patients with Angelman syndrome (AS) determined by its rarest genetic mechanism-uniparental disomy (UPD). The analysis of ours and published patients showed that in UPD, when epilepsy occurred, it was milder compared to patients with deletion, although a suggestive EEG was observed in most patients. We found that UPD patients do not completely fit the scenario delineated for AS, suggesting that patients determined by different mechanisms should be distinctly addressed, for a better understanding of this syndrome.
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Affiliation(s)
- Kette D Valente
- Laboratory of Clinical Neurophysiology, Institute and Department of Psychiatry, University of São Paulo Medical School, R. Jesuíno Arruda 901 Apt. 51, 04532-082 São Paulo, SP, Brazil.
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Borelina D, Engel N, Esperante S, Ferreiro V, Ferrer M, Torrado M, Goldschmidt E, Francipane L, Szijan I. Combined Cytogenetic and Molecular Analyses for the Diagnosis of Prader-Willi/Angelman Syndromes. BMB Rep 2004; 37:522-6. [PMID: 15479613 DOI: 10.5483/bmbrep.2004.37.5.522] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Prader-Willi (PWS) and Angelman (AS) are syndromes of developmental impairment that result from the loss of expression of imprinted genes in the paternal (PWS) or maternal (AS) 15q11-q13 chromosome. Diagnosis on a clinical basis is difficult in newborns and young infants; thus, a suitable molecular test capable of revealing chromosomal abnormalities is required. We used a variety of cytogenetic and molecular approaches, such as, chromosome G banding, fluorescent in situ hybridization, a DNA methylation test, and a set of chromosome 15 DNA polymorphisms to characterize a cohort of 27 PWS patients and 24 suspected AS patients. Molecular analysis enabled the reliable diagnosis of 14 PWS and 7 AS patients, and their classification into four groups: (A) 6 of these 14 PWS subjects (44 %) had deletions of paternal 15q11-q13; (B) 4 of the 7 AS patients had deletions of maternal 15q11-q13; (C) one PWS patient (8 %) had a maternal uniparental disomy (UPD) of chromosome 15; (D) the remaining reliably diagnoses of 7 PWS and 3 AS cases showed abnormal methylation patterns of 15q11-q13 chromosome, but none of the alterations shown by the above groups, although they may have harbored deletions undetected by the markers used. This study highlights the importance of using a combination of cytogenetic and molecular tests for a reliable diagnosis of PWS or AS, and for the identification of genetic alterations.
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Affiliation(s)
- Daniel Borelina
- Genetica y Biologia Molecular, Facultad de Farmacia y Bioquimica, UBA, Buenos Aires, Argentina
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25
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Butler MG, Bittel DC, Kibiryeva N, Talebizadeh Z, Thompson T. Behavioral differences among subjects with Prader-Willi syndrome and type I or type II deletion and maternal disomy. Pediatrics 2004; 113:565-73. [PMID: 14993551 PMCID: PMC6743499 DOI: 10.1542/peds.113.3.565] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To determine whether phenotypic differences exist among individuals with Prader-Willi syndrome with either type I or type II deletions of chromosome 15 or maternal disomy 15 leading to a better understanding of cause and pathophysiology of this classical genetic syndrome. METHODS We analyzed clinical, anthropometric, and behavioral data in 12 individuals (5 men, 7 women; mean age: 25.9 +/- 8.8 years) with PWS and a type I (TI) deletion, 14 individuals (6 men, 8 women; mean age: 19.6 +/- 6.5 years) with PWS and a type II (TII) deletion, and 21 individuals (10 men, 11 women; mean age: 23.6 +/- 9.2 years) with PWS and maternal disomy 15 (UPD). The deletion type was determined by genotyping of DNA markers between proximal chromosome 15 breakpoints BP1 and BP2. TI deletions are approximately 500 kb larger than TII deletions. Several validated psychological and behavioral tests were used to assess phenotypic characteristics of individuals with PWS representing the 3 genetic subtypes. RESULTS Significant differences were found between the 2 deletion groups and those with UPD in multiple psychological and behavioral tests, but no differences were observed in other clinical or anthropometric data studied. Adaptive behavior scores were generally worse in individuals with PWS and the TI deletion, and specific obsessive-compulsive behaviors were more evident in the TI individuals compared with those with UPD. Individuals with PWS with TI deletions also had poorer reading and math skills as well as visual-motor integration. CONCLUSIONS Our study indicates that individuals with TI deletion generally have more behavioral and psychological problems than individuals with the TII deletion or UPD. Four recently identified genes have been identified in the chromosome region between BP1 and BP2 with 1 of the genes (NIPA-1) expressed in mouse brain tissue but not thought to be imprinted. It may be important for brain development or function. These genes are deleted in individuals with TI deletion and are implicated in compulsive behavior and lower intellectual ability in individuals with TI versus TII.
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Affiliation(s)
- Merlin G Butler
- Section of Medical Genetics and Molecular Medicine, Children's Mercy Hospitals and Clinics and University of Missouri-Kansas City School of Medicine, Kansas City, Missouri 64108, USA.
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26
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Borelina D, Esperante S, Gutnisky V, Ferreiro V, Ferrer M, Giliberto F, Frechtel G, Francipane L, Szijan I. Supernumerary marker 15 chromosome in a patient with Prader-Willi syndrome. Clin Genet 2004; 65:242-3. [PMID: 14756675 DOI: 10.1111/j.0009-9163.2004.00203.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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27
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Flori E, Biancalana V, Girard-Lemaire F, Favre R, Flori J, Doray B, Mandel JL. Difficulties of genetic counseling and prenatal diagnosis in a consanguineous couple segregating for the same translocation (14;15) (q11;q13) and at risk for Prader–Willi and Angelman syndromes. Eur J Hum Genet 2003; 12:181-6. [PMID: 14694357 DOI: 10.1038/sj.ejhg.5201134] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are associated with a loss of function of imprinted genes in the 15q11-q13 region mostly due to deletions or uniparental disomies (UPD). These anomalies usually occur de novo with a very low recurrence risk. However, in rare cases, familial translocations are observed, giving rise to a high recurrence risk. We report on the difficulties of genetic counseling and prenatal diagnosis in a family segregating for a translocation (14;15)(q11;q13) where two consanguineous parents carry the same familial translocation in this chromosome 15 imprinting region. Both children of the couple inherited a chromosomal anomaly leading to PWS. However, a paternal 15q11-q13 deletion was responsible for PWS in the first child, whereas prenatal diagnosis demonstrated that PWS was associated with a maternal 15q11-q13 UPD in the fetus. This report demonstrates that both conventional and molecular cytogenetic parental analyses have to be performed when a deletion is responsible for PWS or AS in order not to overlook a familial translocation and to insure reliable diagnosis and genetic counseling.
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Affiliation(s)
- Elisabeth Flori
- Service de Cytogénétique, Fédération de Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
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Valente KD, Andrade JQ, Grossmann RM, Kok F, Fridman C, Koiffmann CP, Marques-Dias MJ. Angelman syndrome: difficulties in EEG pattern recognition and possible misinterpretations. Epilepsia 2003; 44:1051-63. [PMID: 12887436 DOI: 10.1046/j.1528-1157.2003.66502.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE This study aimed to evaluate the sensitivity of the EEG in Angelman syndrome (AS), to verify the age at onset of suggestive EEGs and to study EEG patterns, analyzing variations and comparing our findings with nomenclature previously used. METHODS Seventy EEG and 15 V-EEGs of 26 patients were analyzed. Suggestive EEG patterns of AS were classified in delta pattern (DP), theta pattern (TP), and posterior discharges (PDs). Generic terms were used to simplify the analysis. RESULTS Suggestive EEGs were observed in 25 (96.2%) patients. DP occurred in 22 patients with four variants-hypsarrhythmic-like: irregular, high-amplitude, generalized delta activity (DA) with multifocal epileptiform discharges (EDs); slow variant: regular, high-amplitude, generalized DA with rare EDs; ill-defined slow spike-and-wave: regular, high-amplitude, generalized DA with superimposed EDs characterizing a slow wave, with notched appearance; triphasic-like: rhythmic, moderate-amplitude DA over anterior regions with superimposed EDs. TP was observed in eight patients, as generalized or over the posterior regions. PDs were seen in 19 patients as runs of sharp waves or runs of high-amplitude slow waves with superimposed EDs. TP was the only age-related pattern (younger than 8 years) and observed only in patients with deletion. In 15 patients who had an EEG before the clinical diagnosis, 60% had a suggestive tracing. CONCLUSIONS Although some EEG descriptions are not very detailed, and every author describes findings in a slightly different manner, obviously a common denominator must exist. In this context, EEG seems to be a very sensitive method for the diagnosis of AS, offering an opportunity to corroborate this etiologic diagnosis. Conversely, we do not believe that these patterns may be accounted as specific, except for the delta pattern, which seems to be extremely unusual in other syndromes. Other EEG patterns observed in AS, such as theta activity and PDs, occur in a wide variety of disorders. Nonetheless, their importance for the EEG diagnosis of AS is supported by the fact that they are associated with other features and may be helpful in a proper clinical setting.
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Affiliation(s)
- Kette D Valente
- Laboratory of Clinical Neurophysiology, University of São Paulo Medical School, Brazil.
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29
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Fridman C, Hosomi N, Varela MC, Souza AH, Fukai K, Koiffmann CP. Angelman syndrome associated with oculocutaneous albinism due to an intragenic deletion of the P gene. Am J Med Genet A 2003; 119A:180-3. [PMID: 12749060 DOI: 10.1002/ajmg.a.20105] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Angelman syndrome (AS) is a neurodevelopmental disorder characterized by mental retardation, speech impairment, ataxia, and happy disposition with frequent smiling. AS results from the loss of expression of a maternal imprinted gene, UBE3A, mapped within 15q11-q13 region, due to different mechanisms: maternal deletion, paternal UPD, imprinting center mutation, and UBE3A mutation. Deletion AS patients may exhibit hypopigmentation of skin, eye, and hair correlating with deletion of P gene localized in the distal part of Prader-Willi (PWS)/AS region. Our patient presented developmental delay, severe mental retardation, absence of speech, outbursts of laughter, microcephaly, ataxia, hyperactivity, seizures, white skin, no retinal pigmentation, and gold yellow hair. His parents were of African ancestry. The SNURF-SNRPN methylation analysis confirmed AS diagnosis and microsatellite studies disclosed deletion with breakpoints in BP2 and BP3. All of the 25 exons and flanking introns of the P gene of the patient, his father, and mother were investigated. The patient is hemizygous for the deleted exon 7 of the P gene derived from his father who is a carrier of the deleted allele. Our patient manifests OCA2 associated with AS due to the loss of the maternal chromosome 15 with the normal P allele, and the paternal deletion in the P gene. As various degrees of hypopigmentation are associated with PWS and AS patients, the study of the P gene in a hemizygous state could contribute to the understanding of its effect on human pigmentation during development and to disclose the presence of modifier pigmentation gene(s) in the PWS/AS region.
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Affiliation(s)
- C Fridman
- Department of Biology, University of São Paulo, São Paulo, Brazil.
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Tao SC, Zhang XE, Liu H, Li TX, Zhang ZP, Hu QX, Liang BF. MULTIPLEX PCR FOR SIMULTANEOUS DETECTION OF HUMAN CARCINOMA-RELATED VIRUSES. ANAL LETT 2002. [DOI: 10.1081/al-120005969] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Lossie AC, Whitney MM, Amidon D, Dong HJ, Chen P, Theriaque D, Hutson A, Nicholls RD, Zori RT, Williams CA, Driscoll DJ. Distinct phenotypes distinguish the molecular classes of Angelman syndrome. J Med Genet 2001; 38:834-45. [PMID: 11748306 PMCID: PMC1734773 DOI: 10.1136/jmg.38.12.834] [Citation(s) in RCA: 237] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Angelman syndrome (AS) is a severe neurobehavioural disorder caused by defects in the maternally derived imprinted domain located on 15q11-q13. Most patients acquire AS by one of five mechanisms: (1) a large interstitial deletion of 15q11-q13; (2) paternal uniparental disomy (UPD) of chromosome 15; (3) an imprinting defect (ID); (4) a mutation in the E3 ubiquitin protein ligase gene (UBE3A); or (5) unidentified mechanism(s). All classical patients from these classes exhibit four cardinal features, including severe developmental delay and/or mental retardation, profound speech impairment, a movement and balance disorder, and AS specific behaviour typified by an easily excitable personality with an inappropriately happy affect. In addition, patients can display other characteristics, including microcephaly, hypopigmentation, and seizures. METHODS We restricted the present study to 104 patients (93 families) with a classical AS phenotype. All of our patients were evaluated for 22 clinical variables including growth parameters, acquisition of motor skills, and history of seizures. In addition, molecular and cytogenetic analyses were used to assign a molecular class (I-V) to each patient for genotype-phenotype correlations. RESULTS In our patient repository, 22% of our families had normal DNA methylation analyses along 15q11-q13. Of these, 44% of sporadic patients had mutations within UBE3A, the largest percentage found to date. Our data indicate that the five molecular classes can be divided into four phenotypic groups: deletions, UPD and ID patients, UBE3A mutation patients, and subjects with unknown aetiology. Deletion patients are the most severely affected, while UPD and ID patients are the least. Differences in body mass index, head circumference, and seizure activity are the most pronounced among the classes. CONCLUSIONS Clinically, we were unable to distinguish between UPD and ID patients, suggesting that 15q11-q13 contains the only significant maternally expressed imprinted genes on chromosome 15.
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Affiliation(s)
- A C Lossie
- R C Philips Unit and Division of Genetics, Department of Pediatrics, University of Florida, Gainesville, FL 32610-0296, USA
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Fox R, Yang GS, Feurer ID, Butler MG, Thompson T. Kinetic form discrimination in Prader-Willi syndrome. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2001; 45:317-325. [PMID: 11489053 PMCID: PMC6704469 DOI: 10.1046/j.1365-2788.2001.00326.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Discrimination of the shape of motion-produced forms generated by random elements (i.e. second-order stimuli varying in element density and temporal correlation) was tested in four groups: (1) subjects with Prader-Willi syndrome (PWS), chromosome 15q deletion subtype; (2) subjects with PWS, uniparental maternal disomy (UPD) subtype; (3) equivalent non-PWS controls; and (4) normal controls. The performance of the normal controls exceeded that of all other groups (78% correct, P < 0.009). The PWS deletion (66%) and the equivalent control groups (59%) did not differ (P < 0.95). The UPD group performed significantly less well (38%, P < 0.04) than all the other groups. The performance of the PWS deletion and equivalent control groups is consistent with other data indicating that these populations encounter difficulty meeting the processing demands posed by second-order stimuli. The inferior performance of the UPD group may be attributed to receiving two active alleles of a maternally expressed gene influencing neural development. One candidate is the ubiquitin protein ligase gene (UBE3A), which is maternally expressed only and localized to the 15q region. Other possibilities include the requirement of a paternally expressed gene, residual mosaic trisomy 15 in the brain tissue or complex interactions including specific ratios of differentially spliced gene products.
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Affiliation(s)
- R Fox
- Department of Psychology and John F. Kennedy Center, Vanderbilt University, Nashville, Tennessee, USA.
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Gilmour J, Skuse D, Pembrey M. Hyperphagic short stature and Prader--Willi syndrome: a comparison of behavioural phenotypes, genotypes and indices of stress. Br J Psychiatry 2001; 179:129-37. [PMID: 11483474 DOI: 10.1192/bjp.179.2.129] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND The clinical features of hyperphagic short stature (HSS) include short stature secondary to growth hormone insufficiency, excessive appetite (hyperphagia) and mild learning disabilities. Affected children characteristically live in conditions of high psychosocial stress. Symptoms resolve when the child is removed from the stressful environment. Family studies indicate a genetic predisposition. AIMS To compare the behavioural and stress profiles of HSS with those of Prader--Willi syndrome (PWS), and to test the hypothesis that the genetic locus that predisposes to HSS co-inherits with the PWS locus at 15q11--13. METHOD Twenty-five children with HSS, mean age 9.1 (s.d. 3.8) years, 28% female, were compared with 30 children with PWS, mean age 8.8 (s.d. 2.8) years, 33% female. RESULTS The clinical profiles were largely similar across the conditions, but no evidence was found in HSS of co-inheritance of the PWS critical region. CONCLUSIONS Hyperphagic short stature is one of the very few behavioural diseases associated with a pathognomonic physiological abnormality. Investigations of the suggested genetic dysregulation, which is so sensitive to environmental influences, may well be of importance in a broader context.
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Affiliation(s)
- J Gilmour
- Behavioural Sciences Unit, Institute of Child Health, London, UK
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Diagnosis of Microdeletion Syndromes by Fluorescence in situ Hybridization (
FISH
). ACTA ACUST UNITED AC 2001; Chapter 8:Unit 8.10. [DOI: 10.1002/0471142905.hg0810s14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Fridman C, Varela MC, Kok F, Setian N, Koiffmann CP. Prader-Willi syndrome: genetic tests and clinical findings. GENETIC TESTING 2001; 4:387-92. [PMID: 11216664 DOI: 10.1089/109065700750065144] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Here we describe the genetic studies performed in 53 patients with the suspected diagnosis of Prader-Willi syndrome (PWS). PWS is characterized by neonatal hypotonia, hypogonadism, delayed psychomotor development, hyperphagia, obesity, short stature, small hands and feet, learning disabilities, and obsessive-compulsive behavior. Through the methylation analysis of the SNRPN gene, microsatellite studies of loci mapped within and outside the PWS/AS region, and fluorescence in situ hybridization (FISH) study, we confirmed the diagnosis in 35 patients: 27 with a paternal deletion, and 8 with maternal uniparental disomy (UPD). The clinical comparisons between deleted and UPD patients indicated that there were no major phenotype differences, except for a lower birth length observed in the UPD children. Our sample was composed of more girls than boys; UPD patients were diagnosed earlier than the deleted cohort (2(10/12) s. 7(9/12) years); and, in the deleted group, the boys were diagnosed earlier than the girls (5(2/12) vs. 7(8/12) years, respectively).
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Affiliation(s)
- C Fridman
- Department of Biology, Institute of Bioscience, University of São Paulo, Brazil.
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36
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Ungaro P, Christian SL, Fantes JA, Mutirangura A, Black S, Reynolds J, Malcolm S, Dobyns WB, Ledbetter DH. Molecular characterisation of four cases of intrachromosomal triplication of chromosome 15q11-q14. J Med Genet 2001; 38:26-34. [PMID: 11134237 PMCID: PMC1734721 DOI: 10.1136/jmg.38.1.26] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
CONTEXT Chromosomal abnormalities that involve the proximal region of chromosome 15q occur relatively frequently in the human population. However, interstitial triplications involving one 15 homologue are very rare with three cases reported to date. OBJECTIVE To provide a detailed molecular characterisation of four additional patients with interstitial triplications of chromosome 15q11-q14. DESIGN Molecular analyses were performed using DNA markers and probes specific for the 15q11-q14 region. SETTING Molecular cytogenetics laboratory at the University of Chicago. SUBJECTS Four patients with mild to severe mental retardation and features of Prader-Willi syndrome (PWS) or Angelman syndrome (AS) were referred for molecular cytogenetic analysis following identification of a suspected duplication/triplication of chromosome 15q11-q14 by routine cytogenetic analysis. MAIN OUTCOME MEASURES Fluorescence in situ hybridisation (FISH) was performed to determine the type of chromosomal abnormality present, the extent of the abnormal region, and the orientation of the extra chromosomal segments. Molecular polymorphism analysis was performed to determine the parental origin of the abnormality. Methylation and northern blot analyses of the SNRPN gene were performed to determine the effect of extra copies of the SNRPN gene on its methylation pattern and expression. RESULTS Fluorescence in situ hybridisation (FISH) using probes within and flanking the Prader-Willi/Angelman syndrome critical region indicated that all patients carried an intrachromosomal triplication of proximal 15q11-q14 in one of the two chromosome 15 homologues (trip(15)). In all patients the orientation of the triplicated segments was normal-inverted-normal, suggesting that a common mechanism of rearrangement may have been involved. Microsatellite analysis showed the parental origin of the trip(15) to be maternal in three cases and paternal in one case. The paternal triplication patient had features similar to PWS, one maternal triplication patient had features similar to AS, and the other two maternal triplication patients had non-specific findings including hypotonia and mental retardation. Methylation analysis at exon 1 of the SNRPN locus showed increased dosage of either the paternal or maternal bands in the paternal or maternal triplication patients, respectively, suggesting that the methylation pattern shows a dose dependent increase that correlates with the parental origin of the triplication. In addition, the expression of SNRPN was analysed by northern blotting and expression levels were consistent with dosage and parental origin of the triplication. CONCLUSIONS These four additional cases of trip(15) will provide additional information towards understanding the phenotypic effects of this abnormality and aid in understanding the mechanism of formation of other chromosome 15 rearrangements.
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Affiliation(s)
- P Ungaro
- Department of Human Genetics, University of Chicago, 920 East 58th Street, Chicago, IL 60637, USA
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37
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Fridman C, Koiffmann CP. Origin of uniparental disomy 15 in patients with Prader-Willi or Angelman syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS 2000; 94:249-53. [PMID: 10995513 DOI: 10.1002/1096-8628(20000918)94:3<249::aid-ajmg12>3.0.co;2-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Maternal uniparental disomy (UPD) accounts for approximately 25% of Prader-Willi patients (PWS) and paternal UPD for about 2-5% of Angelman syndrome (AS) patients. These findings and the parental origin of deletions are evidence of genomic imprinting in the cause of PWS and AS. The natural occurrence of UPD individuals allows the study of meiotic mechanisms resulting in chromosomal nondisjunction (ND). We selected patients with UPD15 from our sample of 30 PWS and 40 AS patients to study the origin of ND and the recombination along chromosome 15. These patients were analyzed with 10 microsatellites throughout the entire chromosome 15 (D15S541, D15S542, D15S11, D15S113, GABRB3, CYP19, D15S117, D15S131, D15S984, D15S115). The analysis disclosed seven heterodisomic PWS cases originating by meiosis I (MI) ND (four showed recombination and three no recombination), and one isodisomic PWS UPD15 originating by postzygotic duplication. Among the five paternal UPD15, we detected four isodisomies, three of which showed homozigosity for all markers, corresponding to a mitotic error, and one case originating from a paternal MII ND. Our results indicate that besides maternal MI and MII ND, paternal ND occurs when a PWS UPD15 patient originates from mitotic duplication of the maternal chromosome 15. ND events in AS are mainly due to mitotic errors, but paternal MII ND can occur and give origin to an AS UPD15 individual by two different mechanisms: rescue of a trisomic fetus or fertilization of a nullisomic egg with the disomic sperm, and in this case paternal and maternal ND are necessary.
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Affiliation(s)
- C Fridman
- Department of Biology, Institute of Bioscience, University of Sâo Paulo, Sâo Paulo, Brazil.
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McEntagart ME, Webb T, Hardy C, King MD. Familial Prader-Willi syndrome: case report and a literature review. Clin Genet 2000; 58:216-23. [PMID: 11076044 DOI: 10.1034/j.1399-0004.2000.580309.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Prader-Willi syndrome (PWS) is a neurobehavioural disorder arising through a number of different genetic mechanisms. All involve loss of paternal gene expression from chromosome 15q11q13. Although the majority of cases of PWS are sporadic, precise elucidation of the causative genetic mechanism is essential for accurate genetic counselling as the recurrence risk varies according to the mechanism involved. A pair of siblings affected by PWS is described. Neither demonstrates a microscopically visible deletion in 15q11q13 or maternal disomy. Methylation studies at D15S63 and at the SNRPN locus confirm the diagnosis of PWS. Molecular studies reveal biparental inheritance in both siblings with the exception of D15S128 and D15S63 where no paternal contribution is present indicating a deletion of the imprinting centre. Family studies indicate that the father of the siblings carries the deletion which, he has inherited from his mother. The recurrence risk for PWS in his offspring is 50%.
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Fridman C, Varela MC, Kok F, Diament A, Koiffmann CP. Paternal UPD15: further genetic and clinical studies in four Angelman syndrome patients. AMERICAN JOURNAL OF MEDICAL GENETICS 2000; 92:322-7. [PMID: 10861661 DOI: 10.1002/1096-8628(20000619)92:5<322::aid-ajmg6>3.0.co;2-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Among 25 patients diagnosed with Angelman syndrome, we detected 21 with deletion and 4 with paternal uniparental disomy (UPD), 2 isodisomies originating by postzygotic error, and 1 MII nondisjunction event. The diagnosis was obtained by molecular techniques, including methylation pattern analysis of exon 1 of SNRPN and microsatellite analysis of loci within and outside the 15q11-q13 region. Most manifestations present in deletion patients are those previously reported. Comparing the clinical data from our and published UPD patients with those with deletions we observed the following: the age of diagnosis is higher in UPD group (average 7 3/12 years), microcephaly is more frequent among deletion patients, UPD children start walking earlier (average age 2 9/12 years), whereas in deletion patients the average is 4 (1/2) years, epilepsy started later in UPD patients (average 5 10/12 years) than in deletion patients (average 1 11/12 years), weight above the 75th centile is reported mainly in UPD patients, complete absence of speech is more common in the deleted (88.9%) than in the UPD patients because half of the children are able to say few words. Thus, besides the abnormalities already described, the UPD patients have somewhat better verbal development, a weight above the 75th centile, and OFC in the upper normal range.
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Affiliation(s)
- C Fridman
- Department of Biology, Institute of Bioscience, University of São Paulo, Brazil.
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40
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Roof E, Stone W, MacLean W, Feurer ID, Thompson T, Butler MG. Intellectual characteristics of Prader-Willi syndrome: comparison of genetic subtypes. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2000; 44 ( Pt 1):25-30. [PMID: 10711647 PMCID: PMC6790137 DOI: 10.1046/j.1365-2788.2000.00250.x] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Advances in genetics have led to an increased understanding of the role of the genotype on behavioural functioning. The purpose of the present study was to examine differences in intellectual functioning in individuals with Prader-Willi syndrome (PWS) with a paternal 15q11-q13 deletion versus maternal uniparental disomy (UPD) of chromosome 15. Measures of intelligence and academic achievement were administered to 38 individuals with PWS (24 with deletion and 14 with UPD). The subjects with UPD had significantly higher verbal IQ scores than those with deletion (P< 0.01). The magnitude of the difference in verbal IQ was 9.1 points (69.9 versus 60.8 for UPD and deletion PWS subjects, respectively). Only 17% of subjects with the 15q11-q13 deletion had a verbal IQ > or = 70, while 50% of those with UPD had a verbal IQ > or = 70. Performance IQ scores did not differ between the two PWS genetic subtype groups. This is the first report to document the difference between verbal and performance IQ score patterns among subjects with PWS of the deletion versus the UPD subtype.
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Affiliation(s)
- E Roof
- John F. Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, Tennessee, USA
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41
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Fridman C, Santos M, Ferrari I, Koiffmann CP. A further Angelman syndrome patient with UPD15 due to paternal meiosis II nondisjunction. Clin Genet 2000; 57:86-7. [PMID: 10733242 DOI: 10.1034/j.1399-0004.2000.570114.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Spiro RP, Christian SL, Ledbetter DH, New MI, Wilson RC, Roizen N, Rosenfield RL. Intrauterine growth retardation associated with maternal uniparental disomy for chromosome 6 unmasked by congenital adrenal hyperplasia. Pediatr Res 1999; 46:510-3. [PMID: 10541311 DOI: 10.1203/00006450-199911000-00004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We report the first case of maternal uniparental disomy for chromosome 6 (UPD6mat) ascertained through congenital adrenal hyperplasia (CAH), which arose because of reduction to homozygosity of an autosomal recessive mutation. This case suggests that UPD6mat is associated with intrauterine growth retardation (IUGR). A case of paternal UPD (involving only the short arm of chromosome 6) ascertained as CAH has previously been reported, but was not stated to have IUGR. Our patient was born with IUGR followed by extraordinarily good catch-up growth. She had a history of a marked lag in motor development. She presented at 2.65 y of age with pubarche of 3 mo duration, clitoral enlargement, and an advanced bone age. Simple virilizing CAH was diagnosed by elevations of plasma 17-hydroxyprogesterone and testosterone. Mutation analysis showed that the CAH was due to homozygosity for the 1172N exon 4 mutation. When parental DNA was examined, the mother was found to be heterozygous for the uncommon exon 4 mutation, while the father had no detectable mutations. DNA microsatellite analysis was subsequently performed on the patient and parents using polymorphic markers spanning the entire chromosome 6. Seven markers were informative for inheritance of a single maternal allele and absence of paternal alleles in the proband. Analysis of microsatellite markers from other chromosomes confirmed biparental inheritance at these loci. This combination of findings is diagnostic of UPD6mat. The only other reported case of UPD6mat was discovered serendipitously when genotyped for renal transplantation; this patient had a history of IUGR. Since both cases of UPD6mat had IUGR, the phenotype appears to include IUGR as well as the potential to unmask an autosomal recessive trait.
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Affiliation(s)
- R P Spiro
- Department of Human Genetics, The University of Chicago, Pritzker School of Medicine, Illinois, USA
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43
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Abstract
PURPOSE Prader-Willi syndrome (PWS) refers to a genetic disorder induced by an anomaly on chromosome 15 occurring with a frequency of one in 10,000 to 20,000. It is characterized by a unique set of features including infantile hypotonia, obesity in childhood, small hands and feet, hypogonadism, and mental retardation. Reported here are the results of ophthalmic examinations of persons with PWS, together with results from controls comparable in age, percentage of body fat, and intelligence. These data bear on the hypothesis that the ocular anomalies in PWS are unique to this syndrome. METHOD A comprehensive investigation of PWS brought children and adults to Vanderbilt University for extended testing, which included an ophthalmic examination. Genetic analysis determined unequivocally the PWS diagnosis and identified subgroups-deletion and maternal disomy. A group of persons without PWS but generally comparable in age, body composition, and intelligence served as controls. RESULTS Significant differences between the deletion and disomy subgroups were not found for the clinical ophthalmic measures. The incidence of anomalies in the combined PWS was similar to those reported in previous studies. A similar pattern was present in the control group except for myopia and stereopsis. An effect of genetic subgroup, however, was observed for random element stereopsis with the maternal disomy group having a greater degree of impairment. CONCLUSION The overall similarity between the PWS and control groups on all measures except myopia and stereopsis suggest that many of the anomalies in PWS found in prior studies are due to factors inherent in a general dysfunctional population, rather than reflective of an ocular signature unique to PWS.
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Affiliation(s)
- R Fox
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA
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44
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Muralidhar B, Marney A, Butler MG. Analysis of imprinted genes in subjects with Prader-Willi syndrome and chromosome 15 abnormalities. Genet Med 1999; 1:141-5. [PMID: 11258349 PMCID: PMC6744832 DOI: 10.1097/00125817-199905000-00005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To determine gene expression of five imprinted genes or transcripts from the 15q11-q13 chromosome region using reverse transcription polymerase chain reaction (RT-PCR) in a relatively large survey of Prader-Willi syndrome (PWS) and control subjects with several different chromosome 15 abnormalities. METHODS RT-PCR was undertaken on mRNA isolated from tissue (e.g., mostly lymphoblasts) from 38 PWS and 10 control subjects. DNA primers were used for five imprinted genes or transcripts (ZNF127, SNRPN, PAR5, IPW, and PAR1) from 15q11-q13 and fibrillin, a control gene from 15q21. RESULTS One PWS subject with maternal disomy 15 showed weak but detectable expression of PAR1, whereas SNRPN expression was detected in two PWS subjects [one with the 15q11-q13 deletion and one with a t(15;15) karyotype and maternal disomy 15], and the remaining typical PWS subjects showed no expression of the imprinted genes or transcripts. CONCLUSION No obvious clinical differences were identified in those PWS subjects with weak expression of genes compared with those showing no expression. Although the reason(s) for weak expression is unknown, possible explanations include relaxation of imprinting caused by failure to reset the imprinted genes or transcripts in the maternal germ line or by postzygotic gene expression or undetected chromosome 15 mosaicism in the deletion PWS subjects. The timing, tissue source, and other factors relating to partial expression of genes that are thought to be imprinted may play a role in clinical variability and allow for a better understanding of molecular mechanisms in PWS and other abnormalities of proximal chromosome 15q.
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Affiliation(s)
- B Muralidhar
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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45
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Mohandas T, Park JP, Spellman RA, Filiano JJ, Mamourian AC, Hawk AB, Belloni DR, Noll WW, Moeschler JB. Paternally derived de novo interstitial duplication of proximal 15q in a patient with developmental delay. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1096-8628(19990212)82:4<294::aid-ajmg4>3.0.co;2-u] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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46
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Cassidy SB, Forsythe M, Heeger S, Nicholls RD, Schork N, Benn P, Schwartz S. Comparison of phenotype between patients with Prader-Willi syndrome due to deletion 15q and uniparental disomy 15. ACTA ACUST UNITED AC 1998. [DOI: 10.1002/(sici)1096-8628(19970211)68:4<433::aid-ajmg12>3.0.co;2-t] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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47
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Pena SD. Molecular Cytogenetics II: PCR-based diagnosis of chromosomal deletions and microdeletion syndromes. Genet Mol Biol 1998. [DOI: 10.1590/s1415-47571998000400008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
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48
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Fridman C, Varela MC, Nicholls RD, Koiffmann CP. Unusual clinical features in an Angelman syndrome patient with uniparental disomy due to a translocation 15q15q. Clin Genet 1998; 54:303-8. [PMID: 9831341 DOI: 10.1034/j.1399-0004.1998.5440407.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We had previously described a patient with an overgrowth syndrome and the chromosome constitution 45,XY,t(15q15q) (Wajntal et al., DNA Cell Biol 1993: 12: 227-231). Clinical reassessment and the use of molecular studies, including methylation analysis with an SNRPN probe, microsatellite analyses of D15S11, GABRB3 and D15S113 loci, and fluorescence in situ hybridization (FISH) using the SNRPN and GABRB3 probes, are consistent with a diagnosis of Angelman syndrome (AS) due to paternal isodisomy. This is the fourth report case of a translocation 15q15q with paternal uniparental disomy (UPD). Our findings suggest that some patients with clinical features of AS have hyperphagia and obesity with overgrowth, and that these features should not rule out a diagnosis of AS.
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Affiliation(s)
- C Fridman
- Department of Biology, Institute of Bioscience, University of São Paulo, SP, Brazil.
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49
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Repetto GM, White LM, Bader PJ, Johnson D, Knoll JH. Interstitial duplications of chromosome region 15q11q13: clinical and molecular characterization. AMERICAN JOURNAL OF MEDICAL GENETICS 1998; 79:82-9. [PMID: 9741464 DOI: 10.1002/(sici)1096-8628(19980901)79:2<82::aid-ajmg2>3.0.co;2-p] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Duplications of chromosome region 15q11q13 often occur as a supernumerary chromosome 15. Less frequently they occur as interstitial duplications [dup(15)]. We describe the clinical and molecular characteristics of three patients with de novo dup(15). The patients, two males and one female (ages 3-21 years), had nonspecific findings that included autistic behavior, hypotonia, and variable degrees of mental retardation. The extent, orientation, and parental origin of the duplications were assessed by fluorescent in situ hybridization, microsatellite analyses, and methylation status at D15S63. Two patients had large direct duplications of 15q11q13 [dir dup(15)(q11q13)] that extended through the entire Angelman syndrome/Prader-Willi syndrome (AS/PWS) chromosomal region. Their proximal and distal breaks, at D15S541 or D15S9 and between D15S12 and D15S24, respectively, were comparable to those found in the common AS/PWS deletions. This suggests that duplications and deletions may be the reciprocal product of an unequal recombination event. These two duplications were maternally derived, but the origin of the chromatids involved in the unequal crossing over in meiosis differs. In one patient, the duplication originated from two different maternal chromosomes, while in the other patient it arose from the same maternal chromosome. The third patient had a much smaller duplication that involved only D15S11 and parental origin could not be determined. There was no obvious correlation between phenotype and extent of the duplication in these patients.
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Affiliation(s)
- G M Repetto
- Division of Genetics, Children's Hospital, Boston, Massachusetts 02115, USA
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Jacobsen J, King BH, Leventhal BL, Christian SL, Ledbetter DH, Cook EH. Molecular screening for proximal 15q abnormalities in a mentally retarded population. J Med Genet 1998; 35:534-8. [PMID: 9678696 PMCID: PMC1051362 DOI: 10.1136/jmg.35.7.534] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Paternal or maternal deletions in the 15q11.2-q13 region are known to result in Prader-Willi syndrome (PWS) or Angelman syndrome (AS), respectively. Maternal duplications in 15q11.2-q13 have been found in patients with autism. A population of adults with moderate to profound mental retardation was studied to examine the usefulness of PCR based molecular methods in screening for proximal chromosome 15 abnormalities. Two hundred and eighty-five subjects were initially screened at five microsatellite markers with average heterozygosity values of 0.74 (range 0.54-0.82). Of these subjects, four had a single allele at all five loci, suggestive of a deletion or uniparental isodisomy. The four samples were further screened with additional markers located within 15q11.2-q13 as well as markers telomeric to this region. One subject had uniparental disomy (UPD) and three subjects had a deletion. To determine the parental origin of the 15q11-q13 region containing the single haplotype, samples were analysed with a newly developed methylation specific PCR technique at the SNRPN locus. Each of the four subjects showed presence of the paternal allele and absence of the maternal allele. All cases had a phenotype consistent with Angelman syndrome as expected for the level of mental retardation, but the subject with UPD was distinct from the other subjects with an absence of a history of seizures and presence of bilateral undescended testes and Parkinsonism. Although Angelman syndrome has an estimated population prevalence of 0.008%, at least 1.4% of the moderately to profoundly mentally retarded subjects screened were found to have Angelman syndrome.
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Affiliation(s)
- J Jacobsen
- Department of Psychiatry, University of Chicago, Illinois 60637, USA
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