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Keidai Y, Iwasaki Y, Iwasaki K, Honjo S, Bastepe M, Hamasaki A. Sporadic Pseudohypoparathyroidism Type 1B in Monozygotic Twins: Insights Into the Pathogenesis of Methylation Defects. J Clin Endocrinol Metab 2022; 107:e947-e954. [PMID: 34741517 PMCID: PMC8851915 DOI: 10.1210/clinem/dgab801] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Sporadic pseudohypoparathyroidism type 1B (sporPHP1B) is an imprinting disease without a defined genetic cause, characterized by broad methylation changes in differentially methylated regions (DMRs) of the GNAS gene. OBJECTIVE This work aims to provide insights into the causative event leading to the GNAS methylation defects through comprehensive molecular genetic analyses of a pair of female monozygotic twins concordant for sporPHP1B who were conceived naturally, that is, without assisted reproductive techniques. METHODS Using the leukocyte genome of the twins and family members, we performed targeted bisulfite sequencing, methylation-sensitive restriction enzyme (MSRE)-quantitative polymerase chain reaction (qPCR), whole-genome sequencing (WGS), high-density single-nucleotide polymorphism (SNP) array, and Sanger sequencing. RESULTS Methylation analyses by targeted bisulfite sequencing and MSRE-qPCR revealed almost complete losses of methylation at the GNAS AS, XL, and A/B DMRs and a gain of methylation at the NESP55 DMR in the twins, but not in other family members. Except for the GNAS locus, we did not find apparent methylation defects at other imprinted genome loci of the twins. WGS, SNP array, and Sanger sequencing did not detect the previously described genetic defects associated with familial PHP1B. Sanger sequencing also ruled out any novel genetic alterations in the entire NESP55/AS region. However, the analysis of 28 consecutive SNPs could not exclude the possibility of paternal heterodisomy in a span of 22 kb comprising exon NESP55 and AS exon 5. CONCLUSION Our comprehensive analysis of a pair of monozygotic twins with sporPHP1B ruled out all previously described genetic causes. Twin concordance indicates that the causative event was an imprinting error earlier than the timing of monozygotic twinning.
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Affiliation(s)
- Yamato Keidai
- Department of Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute Kitano Hospital, Osaka, Japan
| | - Yorihiro Iwasaki
- Department of Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute Kitano Hospital, Osaka, Japan
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Kanako Iwasaki
- Department of Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute Kitano Hospital, Osaka, Japan
| | - Sachiko Honjo
- Department of Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute Kitano Hospital, Osaka, Japan
| | - Murat Bastepe
- Endocrine Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Akihiro Hamasaki
- Department of Diabetes and Endocrinology, Tazuke Kofukai Medical Research Institute Kitano Hospital, Osaka, Japan
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Scheps KG, Francipane L, Nevado J, Basack N, Attie M, Bergonzi MF, Cerrone GE, Lapunzina P, Varela V. Multiple copy number variants in a pediatric patient with Hb H disease and intellectual disability. Am J Med Genet A 2016; 170A:986-91. [PMID: 26753516 DOI: 10.1002/ajmg.a.37532] [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: 10/01/2015] [Accepted: 12/11/2015] [Indexed: 11/09/2022]
Abstract
Two distinct syndromes that link α-thalassemia and intellectual disability (ID) have been described: ATR-X, due to mutations in the ATRX gene, and ATR-16, a contiguous gene deletion syndrome in the telomeric region of the short arm of chromosome 16. A critical region where the candidate genes for the ID map has been established. In a pediatric patient with Hemoglobin H disease, dysmorphic features and ID, 4 novel and clinically relevant Copy Number Variants were identified. PCR-GAP, MLPA and FISH analyses established the cause of the α-thalassemia. SNP-array analysis revealed the presence of 4 altered loci: 3 deletions (arr[hg19]Chr16(16p13.3; 88,165-1,507,988) x1; arr[hg19]Chr6(6p21.1; 44,798,701-45,334,537) x1 and arr[hg19]Chr17(17q25.3; 80,544,855-81,057,996) x1) and a terminal duplication (arr[hg19]Chr7(7p22.3-p22.2; 4,935-4,139,785) x3). The -α(3.7) mutation and the ∼1.51 Mb in 16p13.3 are involved in the alpha-thalassemic phenotype. However, the critical region for ATR-16 cannot be narrowed down. The deletion affecting 6p21.1 removes the first 2 exons and part of intron 2 of the RUNX2 gene. Although heterozygous loss of function mutations affecting this gene have been associated with cleidocranial dysplasia, the patient does not exhibit pathognomonic signs of this syndrome, possibly due to the fact that the isoform d of the transcription factor remains unaffected. This work highlights the importance of searching for cryptic deletions in patients with ID and reiterates the need of the molecular analysis when it is associated to microcytic hypochromic anemia with normal iron status.
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Affiliation(s)
- Karen G Scheps
- Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina.,INIGEM (Instituto de Inmunología, Genética y Metabolismo), CONICET- Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Liliana Francipane
- División Genética, Hospital de Clínicas "José de San Martín", Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Julián Nevado
- INGEMM (Instituto de Genética Médica y Molecular), Hospital Universitario La Paz-IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain.,CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Madrid, Spain
| | - Nora Basack
- División Hematología, Hospital de Niños "Dr. Ricardo Gutiérrez", Ciudad de Buenos Aires, Buenos Aires, Argentina
| | - Myriam Attie
- División Hematología, Hospital de Niños "Dr. Ricardo Gutiérrez", Ciudad de Buenos Aires, Buenos Aires, Argentina
| | - María Fernanda Bergonzi
- División Genética, Hospital de Clínicas "José de San Martín", Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Gloria E Cerrone
- Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina.,INIGEM (Instituto de Inmunología, Genética y Metabolismo), CONICET- Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
| | - Pablo Lapunzina
- INGEMM (Instituto de Genética Médica y Molecular), Hospital Universitario La Paz-IdiPaz, Universidad Autónoma de Madrid, Madrid, Spain.,CIBERER (Centro de Investigación Biomédica en Red de Enfermedades Raras), Madrid, Spain
| | - Viviana Varela
- Cátedra de Genética, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina.,INIGEM (Instituto de Inmunología, Genética y Metabolismo), CONICET- Universidad de Buenos Aires, Ciudad de Buenos Aires, Argentina
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Christofolini DM, de Paula Ramos MA, Kulikowski LD, da Silva Bellucco FT, Belangero SIN, Brunoni D, Melaragno MI. Subtelomeric rearrangements and copy number variations in people with intellectual disabilities. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2010; 54:938-942. [PMID: 20807304 DOI: 10.1111/j.1365-2788.2010.01325.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
BACKGROUND The most prevalent type of structural variation in the human genome is represented by copy number variations that can affect transcription levels, sequence, structure and function of genes. METHOD In the present study, we used the multiplex ligation-dependent probe amplification (MLPA) technique and quantitative PCR for the detection of copy number variation in 132 intellectually disabled male patients with normal karyotypes and negative fragile-X-testing. RESULTS Ten of these patients (7.6%) showed copy number variation in the subtelomeric regions, including deletions and duplications. DISCUSSION Duplications of the SECTM1 gene, located at 17q25.3, and of the FLJ22115 gene, located at 20p13, could be associated with phenotype alterations. This study highlights the relevance in the aetiology of intellectual disability of subtelomeric rearrangements that can be screened by MLPA and other molecular techniques.
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Affiliation(s)
- D M Christofolini
- Morphology and Genetics Department, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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Natsuga K, Nishie W, Arita K, Shinkuma S, Nakamura H, Kubota S, Imakado S, Akiyama M, Shimizu H. Complete paternal isodisomy of chromosome 17 in junctional epidermolysis bullosa with pyloric atresia. J Invest Dermatol 2010; 130:2671-4. [PMID: 20596088 DOI: 10.1038/jid.2010.182] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lebre AS, Morinière V, Dunand O, Bensman A, Morichon-Delvallez N, Antignac C. Maternal uniparental heterodisomy of chromosome 17 in a patient with nephropathic cystinosis. Eur J Hum Genet 2009; 17:1019-23. [PMID: 19259134 DOI: 10.1038/ejhg.2009.13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We report maternal uniparental disomy of chromosome 17 (mat UPD17) in a 2.5-year-old girl presenting infantile cystinosis. This patient was homozygous for the 57 kb deletion encompassing the CTNS gene, frequently found in patients from the European origin. The proband's mother was heterozygous for the deletion and the father did not carry the deletion. We carried out haplotype analysis with polymorphic markers spanning the whole chromosome 17. Informative markers showed the presence of two maternal alleles but no paternal allele for regions spanning the 17q arm and the proximal half of 17p, and only one maternal allele on the distal 17p arm. As deletion of half of 17p is probably not viable, these results suggest mat UPD17 with heterodisomy of 17q and proximal 17p and isodisomy of distal 17p. This is the first demonstration of mat UPD17, in particular of isodisomy 17p, in cystinosis.
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Affiliation(s)
- Anne-Sophie Lebre
- AP-HP, Hôpital Necker-Enfants Malades, Département de génétique, Paris, France
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Vazna A, Havlovicova M, Sedlacek Z. Molecular cloning and analysis of breakpoints on ring chromosome 17 in a patient with autism. Gene 2008; 407:186-92. [DOI: 10.1016/j.gene.2007.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 10/02/2007] [Accepted: 10/05/2007] [Indexed: 10/22/2022]
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Havlovicova M, Novotna D, Kocarek E, Novotna K, Bendova S, Petrak B, Hrdlicka M, Sedlacek Z. A girl with neurofibromatosis type 1, atypical autism and mosaic ring chromosome 17. Am J Med Genet A 2007; 143A:76-81. [PMID: 17163520 DOI: 10.1002/ajmg.a.31569] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We describe a girl with neurofibromatosis type 1 (NF1), mild dysmorphic features, growth and mental retardation, autism, and mosaicism of ring chromosome 17 and chromosome 17 monosomy. The extent of genetic material deleted from the ring chromosome was determined using a combination of classical cytogenetics, fluorescence in situ hybridization (FISH) and multiplex ligation-dependent probe amplification (MLPA) to be 0.6-2.5 Mb on 17p, and up to about 10 Mb on 17q. Based on our observations and on a review of the literature we argue that in addition to a universal "ring syndrome" which is based on ring instability and is less specific for the chromosome involved, various ring chromosomes underlie their own characteristic phenotypes. We propose that the symptoms leading to the diagnosis of NF1 in our patient could be attributed to mosaic hemizygosity for the NF1 gene in some of her somatic cells. A similar mechanism or a direct involvement of respective disease genes in the aberration could possibly influence also the development of autism and other symptoms. We raise a question if the loss of one copy of chromosome 17 from a substantial fraction of somatic cells can have specific consequences also for future risks of the patient, for example, due to the mosaic hemizygosity for the BRCA1 and TP53 genes.
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Affiliation(s)
- Marketa Havlovicova
- Institute of Biology and Medical Genetics, Charles University Second Medical School and University Hospital Motol, Prague, Czech Republic.
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Nazarenko S, Sazhenova E, Baumer A, Schinzel A. Segmental maternal heterodisomy of the proximal part of chromosome 15 in an infant with Prader–Willi syndrome. Eur J Hum Genet 2004; 12:411-4. [PMID: 14997184 DOI: 10.1038/sj.ejhg.5201168] [Citation(s) in RCA: 11] [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
Uniparental disomy (UPD) 15, detected in patients with Prader-Willi (PWS) and Angelman syndromes, has to date always involved the entire chromosome 15. We report the first case of segmental maternal uniparental heterodisomy confined to a proximal part of chromosome 15 in a child with clinical features of PWS. This unusual finding can be explained by the rare combination of three consecutive events: a trisomy 15 zygote caused by a maternal meiosis I error, early postzygotic mitotic recombination between maternal and paternal chromatids, and, finally, trisomy rescue by the loss of the rearranged chromosome 15 containing the paternal 15q11-q13 segment.
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Affiliation(s)
- Sergey Nazarenko
- Institute of Medical Genetics, Russian Academy of Medical Sciences, Tomsk, Russia
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Rio M, Molinari F, Heuertz S, Ozilou C, Gosset P, Raoul O, Cormier-Daire V, Amiel J, Lyonnet S, Le Merrer M, Turleau C, de Blois MC, Prieur M, Romana S, Vekemans M, Munnich A, Colleaux L. Automated fluorescent genotyping detects 10% of cryptic subtelomeric rearrangements in idiopathic syndromic mental retardation. J Med Genet 2002; 39:266-70. [PMID: 11950856 PMCID: PMC1735076 DOI: 10.1136/jmg.39.4.266] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
Recent studies have shown that cryptic unbalanced subtelomeric rearrangements contribute to a significant proportion of idiopathic syndromic mental retardation cases. Using a fluorescent genotyping based strategy, we found a 10% rate of cryptic subtelomeric rearrangements in a large series of 150 probands with severe idiopathic syndromic mental retardation and normal RHG-GTG banded karyotype. Fourteen children were found to carry deletions or duplications of one or more chromosome telomeres and two children had uniparental disomy. This study clearly shows that fluorescent genotyping is a sensitive and cost effective method that not only detects cryptic subtelomeric rearrangements but also provides a unique opportunity to detect uniparental disomies. We suggest giving consideration to systematic examination of subtelomeric regions in the diagnostic work up of patients with unexplained syndromic mental retardation.
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Affiliation(s)
- M Rio
- Unité de Recherches sur les Handicaps Génétiques de l'Enfant, INSERM U-393, et Département de Génétique, Hôpital Necker-Enfants Malades, Paris, France
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