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Zhang Y, Liu X, Gao H, Cui W, Zhang B, Zhao Y. Molecular and phenotypic characteristics of 15q24 microdeletion in pediatric patients with developmental disorders. Mol Cytogenet 2021; 14:57. [PMID: 34922566 PMCID: PMC8684056 DOI: 10.1186/s13039-021-00574-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/03/2021] [Indexed: 11/18/2022] Open
Abstract
Chromosome 15q24 microdeletion is a rare genetic disorder characterized by development delay, facial dysmorphism, congenital malformations, and occasional autism spectrum disorder (ASD). In this study, we identified five cases of 15q24 microdeletion using multiplex ligation-dependent probe amplification (MLPA) technology in a cohort of patients with developmental delay and/or intellectual disability. Two of these five cases had deletions that overlapped with the previously defined 1.1 Mb region observed in most reported cases. Two cases had smaller deletions (< 0.57 Mb) in the 15q24.1 low copy repeat (LCR) B-C region. They presented significant neurobehavioral features, suggesting that this smaller interval is critical for core phenotypes of 15q24 microdeletion syndrome. One case had minimal homozygous deletion of less than 0.11 Mb in the 15q24.1 LCR B-C region, which contained CYP1A1 (cytochrome P450 family 1 subfamily A member 1) and EDC3 (enhancer of mRNA decapping 3) genes, resulting in poor immunity, severe laryngeal stridor, and lower limbs swelling. This study provides additional evidence of 15q24 microdeletion syndrome with genetic and clinical findings. The results will be of significance to pediatricians in their daily practice.
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Affiliation(s)
- Yuanyuan Zhang
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, Liaoning, China
| | - Xiaoliang Liu
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, Liaoning, China
| | - Haiming Gao
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, Liaoning, China
| | - Wanting Cui
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, Liaoning, China
| | - Bijun Zhang
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, Liaoning, China
| | - Yanyan Zhao
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, Liaoning, China.
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2
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Liu Y, Zhang Y, Zarrei M, Dong R, Yang X, Zhao D, Scherer SW, Gai Z. Refining critical regions in 15q24 microdeletion syndrome pertaining to autism. Am J Med Genet B Neuropsychiatr Genet 2020; 183:217-226. [PMID: 31953991 DOI: 10.1002/ajmg.b.32778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 11/29/2019] [Accepted: 12/16/2019] [Indexed: 12/26/2022]
Abstract
Chromosome 15q24 microdeletion syndrome is characterized by developmental delay, facial dysmorphism, hearing loss, hypotonia, recurrent infection, and other congenital malformations including microcephaly, scoliosis, joint laxity, digital anomalies, as well as sometimes having autism spectrum disorder (ASD) and attention deficit hyperactivity disorder. Here, we report a boy with a 2.58-Mb de novo deletion at chromosome 15q24. He is diagnosed with ASD and having multiple phenotypes similar to those reported in cases having 15q24 microdeletion syndrome. To delineate the critical genes and region that might be responsible for these phenotypes, we reviewed all previously published cases. We observe a potential minimum critical region of 650 kb (LCR15q24A-B) affecting NEO1 among other genes that might pertinent to individuals with ASD carrying this deletion. In contrast, a previously defined minimum critical region downstream of the 650-kb interval (LCR15q24B-D) is more likely associated with the developmental delay, facial dysmorphism, recurrent infection, and other congenital malformations. As a result, the ASD phenotype in this individual is potentially attributed by genes particularly NEO1 within the newly proposed critical region.
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Affiliation(s)
- Yi Liu
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Yanqing Zhang
- Pediatric Health Care Institute, Qilu Children's Hospital of Shandong University, Ji'nan, 250022, China
| | - Mehdi Zarrei
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Rui Dong
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Xiaomeng Yang
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Dongmei Zhao
- Pediatric Health Care Institute, Qilu Children's Hospital of Shandong University, Ji'nan, 250022, China
| | - Stephen W Scherer
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Ontario, Canada.,McLaughlin Centre and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Zhongtao Gai
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
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3
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Liu Y, Mapow B. Coexistence of urogenital malformations in a female fetus with de novo 15q24 microdeletion and a literature review. Mol Genet Genomic Med 2020; 8:e1265. [PMID: 32400031 PMCID: PMC7336734 DOI: 10.1002/mgg3.1265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 12/13/2022] Open
Abstract
Background 15q24 microdeletion is a relatively new syndrome caused by nonallelic homologous recombination (NAHR) between low‐copy repeats (LCRs) in the 15q24 chromosome region. This syndrome is characterized by a spectrum of clinical symptoms including global developmental delay, intellectual disability, facial dysmorphisms, and congenital malformations of the extremities, eye, gastrointestinal tract, genitourinary system, and genitalia. Method Molecular cytogenetic analysis was performed using whole genome single‐nucleotide polymorphism (SNP) microarray analysis. Autopsy examination including gross and microscopic examination were performed. In addition, a thorough review of the literature on 15q24 microdeletion was completed and summarized in table format. Result Molecular cytogenetic analysis revealed a 3.88 MB interstitial deletion within 15q24.1 to 15q24.3 (74,353,735–78,228,485 bp) in our case. Autopsy examination showed congenital malformations within the genitourinary system and genitalia, including left kidney agenesis and uterus didelphys. After thorough literature review, we found a series of midline defects associated with 15q24 microdeletion syndrome. Conclusion We report the first case of coexistence of urogenital abnormalities, including left kidney agenesis and uterus didelphys, with 15q24 microdeletion syndrome, which is also associated with midline defects secondary to abnormal development. Since 15q24 microdeletion syndrome is a relatively new entity, fully characterizing its variation and severity requires additional examination of the genetics, molecular profile and structural and functional abnormalities in affected patients. Due to the limited data in the literature, statistical analysis of abnormalities in each organ system is not possible. However, we can predict that novel genetic pathways involving cell migration, adhesion, apoptosis, and embryo development might be discovered with the advanced study of 15q24 microdeletion syndrome.
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Affiliation(s)
- Yaobin Liu
- Department of Pathology, Pennsylvania Hospital, Philadelphia, Pennsylvania, USA
| | - Beth Mapow
- Department of Pathology and Laboratory Medicine, Jefferson Health New jersey, Cherry Hill, New Jersey, USA
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NEIL1 is a candidate gene associated with common variable immunodeficiency in a patient with a chromosome 15q24 deletion. Clin Immunol 2017; 176:71-76. [PMID: 28093361 DOI: 10.1016/j.clim.2017.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 02/07/2023]
Abstract
We report the first patient with an interstitial deletion of chromosome 15q24.1-q24.3 associated with common variable immunodeficiency (CVID). The 18-year old female patient's clinical and immunological phenotype was compared with 8 additional previously published patients with chr15q24 deletions. A CGH analysis estimated the deletion to be 3.767Mb in size (chr15: 74,410,916-78,178,418) and the result was confirmed using qRT-PCR. We defined an immune-related commonly deleted region (ICDR) within the chromosomal band 15q24.2, deleted in all four patients with different forms of antibody deficiencies. Mutations in the 14 genes within this ICDR were not identified in the remaining allele in our patient by WES and gene expression analyses showed haploinsufficiency of all the genes. Among these genes, we consider Nei Like DNA Glycosylase 1 (NEIL1) as a likely candidate gene due to its crucial role in B-cell activation and terminal differentiation.
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Witteveen JS, Willemsen MH, Dombroski TCD, van Bakel NHM, Nillesen WM, van Hulten JA, Jansen EJR, Verkaik D, Veenstra-Knol HE, van Ravenswaaij-Arts CMA, Wassink-Ruiter JSK, Vincent M, David A, Le Caignec C, Schieving J, Gilissen C, Foulds N, Rump P, Strom T, Cremer K, Zink AM, Engels H, de Munnik SA, Visser JE, Brunner HG, Martens GJM, Pfundt R, Kleefstra T, Kolk SM. Haploinsufficiency of MeCP2-interacting transcriptional co-repressor SIN3A causes mild intellectual disability by affecting the development of cortical integrity. Nat Genet 2016; 48:877-87. [PMID: 27399968 DOI: 10.1038/ng.3619] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 06/15/2016] [Indexed: 12/13/2022]
Abstract
Numerous genes are associated with neurodevelopmental disorders such as intellectual disability and autism spectrum disorder (ASD), but their dysfunction is often poorly characterized. Here we identified dominant mutations in the gene encoding the transcriptional repressor and MeCP2 interactor switch-insensitive 3 family member A (SIN3A; chromosome 15q24.2) in individuals who, in addition to mild intellectual disability and ASD, share striking features, including facial dysmorphisms, microcephaly and short stature. This phenotype is highly related to that of individuals with atypical 15q24 microdeletions, linking SIN3A to this microdeletion syndrome. Brain magnetic resonance imaging showed subtle abnormalities, including corpus callosum hypoplasia and ventriculomegaly. Intriguingly, in vivo functional knockdown of Sin3a led to reduced cortical neurogenesis, altered neuronal identity and aberrant corticocortical projections in the developing mouse brain. Together, our data establish that haploinsufficiency of SIN3A is associated with mild syndromic intellectual disability and that SIN3A can be considered to be a key transcriptional regulator of cortical brain development.
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Affiliation(s)
- Josefine S Witteveen
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, the Netherlands
| | - Marjolein H Willemsen
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
| | - Thaís C D Dombroski
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, the Netherlands
| | - Nick H M van Bakel
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, the Netherlands
| | - Willy M Nillesen
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
| | - Josephus A van Hulten
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, the Netherlands
| | - Eric J R Jansen
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, the Netherlands
| | - Dave Verkaik
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
| | - Hermine E Veenstra-Knol
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | | | | | - Marie Vincent
- Centre Hospitalier Universitaire de Nantes, Service de Génétique Médicale, Nantes, France
| | - Albert David
- Centre Hospitalier Universitaire de Nantes, Service de Génétique Médicale, Nantes, France
| | - Cedric Le Caignec
- Centre Hospitalier Universitaire de Nantes, Service de Génétique Médicale, Nantes, France.,Laboratoire de Physiopathologie de la Résorption Osseuse et Thérapie des Tumeurs Osseuses Primitives, Faculté de Médecine, INSERM UMRS 957, Nantes, France
| | - Jolanda Schieving
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
| | - Nicola Foulds
- Wessex Clinical Genetics Services, University Hospital Southampton National Health Service Foundation Trust, Princess Anne Hospital, Southampton, UK.,Department of Human Genetics and Genomic Medicine, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Patrick Rump
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Tim Strom
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Kirsten Cremer
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | | | - Hartmut Engels
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Sonja A de Munnik
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
| | - Jasper E Visser
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, the Netherlands.,Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Neurology, Amphia Hospital Breda, Berda, the Netherlands
| | - Han G Brunner
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
| | - Gerard J M Martens
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, the Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
| | - Tjitske Kleefstra
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
| | - Sharon M Kolk
- Department of Molecular Animal Physiology, Donders Institute for Brain, Cognition and Behavior, Radboud University, Nijmegen, the Netherlands
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Unmasking a novel disease gene NEO1 associated with autism spectrum disorders by a hemizygous deletion on chromosome 15 and a functional polymorphism. Behav Brain Res 2016; 300:135-42. [DOI: 10.1016/j.bbr.2015.10.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 10/14/2015] [Accepted: 10/21/2015] [Indexed: 11/20/2022]
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Palazón-Bru A, Ramírez-Prado D, Cortés E, Aguilar-Segura MS, Gil-Guillén VF. An inferential study of the phenotype for the chromosome 15q24 microdeletion syndrome: a bootstrap analysis. PeerJ 2016; 4:e1641. [PMID: 26925314 PMCID: PMC4768676 DOI: 10.7717/peerj.1641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 01/08/2016] [Indexed: 11/21/2022] Open
Abstract
In January 2012, a review of the cases of chromosome 15q24 microdeletion syndrome was published. However, this study did not include inferential statistics. The aims of the present study were to update the literature search and calculate confidence intervals for the prevalence of each phenotype using bootstrap methodology. Published case reports of patients with the syndrome that included detailed information about breakpoints and phenotype were sought and 36 were included. Deletions in megabase (Mb) pairs were determined to calculate the size of the interstitial deletion of the phenotypes studied in 2012. To determine confidence intervals for the prevalence of the phenotype and the interstitial loss, we used bootstrap methodology. Using the bootstrap percentiles method, we found wide variability in the prevalence of the different phenotypes (3–100%). The mean interstitial deletion size was 2.72 Mb (95% CI [2.35–3.10 Mb]). In comparison with our work, which expanded the literature search by 45 months, there were differences in the prevalence of 17% of the phenotypes, indicating that more studies are needed to analyze this rare disease.
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Affiliation(s)
- Antonio Palazón-Bru
- Department of Clinical Medicine, Miguel Hernández University, San Juan de Alicante, Alicante, Spain; Research Unit, Elda Hospital, Elda, Alicante, Spain
| | - Dolores Ramírez-Prado
- Clinical Analysis Department, Elda Hospital, Elda, Alicante, Spain; Pharmacology, Pediatrics and Organic Chemistry Department, Miguel Hernández University, San Juan de Alicante, Alicante, Spain
| | - Ernesto Cortés
- Pharmacology, Pediatrics and Organic Chemistry Department, Miguel Hernández University , San Juan de Alicante, Alicante , Spain
| | - María Soledad Aguilar-Segura
- Pharmacology, Pediatrics and Organic Chemistry Department, Miguel Hernández University , San Juan de Alicante, Alicante , Spain
| | - Vicente Francisco Gil-Guillén
- Department of Clinical Medicine, Miguel Hernández University, San Juan de Alicante, Alicante, Spain; Research Unit, Elda Hospital, Elda, Alicante, Spain
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8
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Inherited 15q24 microdeletion syndrome in twins and their father with phenotypic variability. Eur J Med Genet 2015; 58:111-5. [DOI: 10.1016/j.ejmg.2014.12.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 12/01/2014] [Indexed: 11/20/2022]
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9
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Abstract
Abnormal cortical circuits underlie some cognitive and psychiatric disorders, yet the molecular signals that generate normal cortical networks remain poorly understood. Semaphorin 7A (Sema7A) is an atypical member of the semaphorin family that is GPI-linked, expressed principally postnatally, and enriched in sensory cortex. Significantly, SEMA7A is deleted in individuals with 15q24 microdeletion syndrome, characterized by developmental delay, autism, and sensory perceptual deficits. We studied the role that Sema7A plays in establishing functional cortical circuitry in mouse somatosensory barrel cortex. We found that Sema7A is expressed in spiny stellate cells and GABAergic interneurons and that its absence disrupts barrel cytoarchitecture, reduces asymmetrical orientation of spiny stellate cell dendrites, and functionally impairs thalamocortically evoked synaptic responses, with reduced feed-forward GABAergic inhibition. These data identify Sema7A as a regulator of thalamocortical and local circuit development in layer 4 and provide a molecular handle that can be used to explore the coordinated generation of excitatory and inhibitory cortical circuits.
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10
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Gao X, Gotway G, Rathjen K, Johnston C, Sparagana S, Wise CA. Genomic Analyses of Patients With Unexplained Early-Onset Scoliosis. Spine Deform 2014; 2:324-332. [PMID: 27927329 PMCID: PMC4228381 DOI: 10.1016/j.jspd.2014.04.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 03/17/2014] [Accepted: 04/21/2014] [Indexed: 12/20/2022]
Abstract
STUDY DESIGN To test for rare genetic mutations, a cohort of patients with unexplained early-onset scoliosis (EOS) was screened using high-density microarray genotyping. A cohort of patients with adolescent idiopathic scoliosis (AIS) was similarly screened and the results were compared. SUMMARY OF BACKGROUND DATA Patients with scoliosis in infancy or early childhood (EOS) are at high risk for progressive deformity and associated problems including respiratory compromise. Early-onset scoliosis is frequently associated with genetic disorders but many patients present with nonspecific clinical features and without an associated diagnosis. The authors hypothesized that EOS in these patients may be caused by rare genetic mutations detectable by next-generation genomic methods. METHODS The researchers identified 24 patients with unexplained EOS from pediatric orthopedic clinics. They genotyped them, along with 39 connecting family members, using the Illumina OmniExpress-12, version 1.0 beadchip. Resulting genotypes were analyzed for chromosomal changes, specifically copy number variation and absence of heterozygosity. They screened 482 adolescent idiopathic scoliosis (AIS) patients and 744 healthy controls, who were similarly genotyped with the same beadchip, for chromosomal changes identified in the EOS cohort. RESULTS Copy number variation and absence of heterozygosity analyses revealed a genetic diagnosis of chromosome 15q24 microdeletion syndrome in 1 patient and maternal uniparental disomy of chromosome 14 in a second one. Prior genetic testing and clinical evaluations had been negative in both cases. A large novel chromosome 10 deletion was likely causal in a third EOS patient. These mutations identified in the EOS patients were absent in AIS patients and controls, and thus were not associated with AIS or found in asymptomatic individuals. CONCLUSIONS These data underscore the usefulness of updated genetic evaluations including high-density microarray-based genotyping and other next-generation methods in patients with unexplained EOS, even when prior genetic studies were negative. These data also suggest the intriguing possibility that other mutations detectable by whole genome sequencing, as well as epigenetic effects, await discovery in the EOS population.
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Affiliation(s)
- Xiaochong Gao
- Sarah M. and Charles E. Seay Center for Musculoskeletal Research, Texas Scottish Rite Hospital for Children. Dallas, TX
| | - Garrett Gotway
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Karl Rathjen
- Department of Orthopedic Surgery, Texas Scottish Rite Hospital for Children. Dallas, TX,Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, TX
| | - Charles Johnston
- Department of Orthopedic Surgery, Texas Scottish Rite Hospital for Children. Dallas, TX,Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, TX
| | - Steven Sparagana
- Department of Neurology, Texas Scottish Rite Hospital for Children. Dallas, TX,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX
| | - Carol A. Wise
- Sarah M. and Charles E. Seay Center for Musculoskeletal Research, Texas Scottish Rite Hospital for Children. Dallas, TX,Department of Orthopaedic Surgery, University of Texas Southwestern Medical Center, Dallas, TX,McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, TX,To whom correspondence should be directed. Telephone: 214-559-7861 Fax: 214-559-7872
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Watson CT, Marques-Bonet T, Sharp AJ, Mefford HC. The genetics of microdeletion and microduplication syndromes: an update. Annu Rev Genomics Hum Genet 2014; 15:215-244. [PMID: 24773319 DOI: 10.1146/annurev-genom-091212-153408] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Chromosomal abnormalities, including microdeletions and microduplications, have long been associated with abnormal developmental outcomes. Early discoveries relied on a common clinical presentation and the ability to detect chromosomal abnormalities by standard karyotype analysis or specific assays such as fluorescence in situ hybridization. Over the past decade, the development of novel genomic technologies has allowed more comprehensive, unbiased discovery of microdeletions and microduplications throughout the human genome. The ability to quickly interrogate large cohorts using chromosome microarrays and, more recently, next-generation sequencing has led to the rapid discovery of novel microdeletions and microduplications associated with disease, including very rare but clinically significant rearrangements. In addition, the observation that some microdeletions are associated with risk for several neurodevelopmental disorders contributes to our understanding of shared genetic susceptibility for such disorders. Here, we review current knowledge of microdeletion/duplication syndromes, with a particular focus on recurrent rearrangement syndromes.
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Affiliation(s)
- Corey T Watson
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Tomas Marques-Bonet
- Institut de Biologia Evolutiva, Universitat Pompeu Fabra/CSIC, 08003 Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain.,Centro Nacional de Análisis Genómico, 08023 Barcelona, Spain
| | - Andrew J Sharp
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Heather C Mefford
- Department of Pediatrics, University of Washington, Seattle, Washington 98195
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12
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Carvill GL, Mefford HC. Microdeletion syndromes. Curr Opin Genet Dev 2013; 23:232-9. [PMID: 23664828 DOI: 10.1016/j.gde.2013.03.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 03/11/2013] [Accepted: 03/25/2013] [Indexed: 01/11/2023]
Abstract
The recent explosion in the implementation of genome-wide microarray technology to discover rare, pathogenic genomic rearrangements in a variety of diseases has led to the discovery of numerous microdeletion syndromes. It is now clear that these microdeletions are associated with extensive phenotypic heterogeneity and incomplete penetrance. A subset of recurrent microdeletions underpin diverse phenotypes, including intellectual disability, autism, epilepsy and neuropsychiatric disorders. Recent studies highlight a role for additional low frequency variants, or 'second hits' to account for this variability. The implementation of massively parallel sequencing and epigenetic models may provide a powerful prospective approach to the delineation of microdeletion syndrome phenotypes.
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Affiliation(s)
- Gemma L Carvill
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
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13
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Individual variation of the genetic response to bisphenol a in human foreskin fibroblast cells derived from cryptorchidism and hypospadias patients. PLoS One 2012; 7:e52756. [PMID: 23285176 PMCID: PMC3532342 DOI: 10.1371/journal.pone.0052756] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 11/20/2012] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND/PURPOSE We hypothesized that polymorphic differences among individuals might cause variations in the effect that environmental endocrine disruptors (EEDs) have on male genital malformations (MGMs). In this study, individual variation in the genetic response to low-dose bisphenol A (BPA) was investigated in human foreskin fibroblast cells (hFFCs) derived from child cryptorchidism (CO) and hypospadias (HS) patients. METHODOLOGY/PRINCIPAL FINDINGS hFFCs were collected from control children without MGMs (n=5) and child CO and HS patients (n=8 and 21, respectively). BPA exposure (10 nM) was found to inhibit matrix metalloproteinase-11 (MMP11) expression in the HS group (0.74-fold, P=0.0034) but not in the control group (0.93-fold, P=0.84) and CO group (0.94-fold, P=0.70). Significantly lower levels of MMP11 expression were observed in the HS group compared with the control group (0.80-fold, P=0.0088) and CO group (0.79-fold, P=0.039) in response to 10 nM BPA. The effect of single-nucleotide polymorphism rs5000770 (G>A), located within the aryl hydrocarbon receptor nuclear translocator 2 (ARNT2) locus, on individual sensitivity to low-dose BPA was investigated in the HS group. A significant difference in neurotensin receptor 1 (NTSR1) expression in response to 10 nM BPA was observed between AA and AG/GG groups (n=6 and 15, respectively. P=0.031). However, no significant difference in ARNT2 expression was observed (P=0.18). CONCLUSIONS/SIGNIFICANCE This study advances our understanding of the specificity of low-dose BPA effects on human reproductive health. Our results suggest that genetic variability among individuals affects susceptibility to the effects of EEDs exposure as a potential cause of HS.
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Doelken SC, Köhler S, Mungall CJ, Gkoutos GV, Ruef BJ, Smith C, Smedley D, Bauer S, Klopocki E, Schofield PN, Westerfield M, Robinson PN, Lewis SE. Phenotypic overlap in the contribution of individual genes to CNV pathogenicity revealed by cross-species computational analysis of single-gene mutations in humans, mice and zebrafish. Dis Model Mech 2012; 6:358-72. [PMID: 23104991 PMCID: PMC3597018 DOI: 10.1242/dmm.010322] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Numerous disease syndromes are associated with regions of copy number variation (CNV) in the human genome and, in most cases, the pathogenicity of the CNV is thought to be related to altered dosage of the genes contained within the affected segment. However, establishing the contribution of individual genes to the overall pathogenicity of CNV syndromes is difficult and often relies on the identification of potential candidates through manual searches of the literature and online resources. We describe here the development of a computational framework to comprehensively search phenotypic information from model organisms and single-gene human hereditary disorders, and thus speed the interpretation of the complex phenotypes of CNV disorders. There are currently more than 5000 human genes about which nothing is known phenotypically but for which detailed phenotypic information for the mouse and/or zebrafish orthologs is available. Here, we present an ontology-based approach to identify similarities between human disease manifestations and the mutational phenotypes in characterized model organism genes; this approach can therefore be used even in cases where there is little or no information about the function of the human genes. We applied this algorithm to detect candidate genes for 27 recurrent CNV disorders and identified 802 gene-phenotype associations, approximately half of which involved genes that were previously reported to be associated with individual phenotypic features and half of which were novel candidates. A total of 431 associations were made solely on the basis of model organism phenotype data. Additionally, we observed a striking, statistically significant tendency for individual disease phenotypes to be associated with multiple genes located within a single CNV region, a phenomenon that we denote as pheno-clustering. Many of the clusters also display statistically significant similarities in protein function or vicinity within the protein-protein interaction network. Our results provide a basis for understanding previously un-interpretable genotype-phenotype correlations in pathogenic CNVs and for mobilizing the large amount of model organism phenotype data to provide insights into human genetic disorders.
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Affiliation(s)
- Sandra C Doelken
- Institute for Medical and Human Genetics, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany
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15
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Girirajan S, Rosenfeld JA, Coe BP, Parikh S, Friedman N, Goldstein A, Filipink RA, McConnell JS, Angle B, Meschino WS, Nezarati MM, Asamoah A, Jackson KE, Gowans GC, Martin JA, Carmany EP, Stockton DW, Schnur RE, Penney LS, Martin DM, Raskin S, Leppig K, Thiese H, Smith R, Aberg E, Niyazov DM, Escobar LF, El-Khechen D, Johnson KD, Lebel RR, Siefkas K, Ball S, Shur N, McGuire M, Brasington CK, Spence JE, Martin LS, Clericuzio C, Ballif BC, Shaffer LG, Eichler EE. Phenotypic heterogeneity of genomic disorders and rare copy-number variants. N Engl J Med 2012; 367:1321-31. [PMID: 22970919 PMCID: PMC3494411 DOI: 10.1056/nejmoa1200395] [Citation(s) in RCA: 412] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND Some copy-number variants are associated with genomic disorders with extreme phenotypic heterogeneity. The cause of this variation is unknown, which presents challenges in genetic diagnosis, counseling, and management. METHODS We analyzed the genomes of 2312 children known to carry a copy-number variant associated with intellectual disability and congenital abnormalities, using array comparative genomic hybridization. RESULTS Among the affected children, 10.1% carried a second large copy-number variant in addition to the primary genetic lesion. We identified seven genomic disorders, each defined by a specific copy-number variant, in which the affected children were more likely to carry multiple copy-number variants than were controls. We found that syndromic disorders could be distinguished from those with extreme phenotypic heterogeneity on the basis of the total number of copy-number variants and whether the variants are inherited or de novo. Children who carried two large copy-number variants of unknown clinical significance were eight times as likely to have developmental delay as were controls (odds ratio, 8.16; 95% confidence interval, 5.33 to 13.07; P=2.11×10(-38)). Among affected children, inherited copy-number variants tended to co-occur with a second-site large copy-number variant (Spearman correlation coefficient, 0.66; P<0.001). Boys were more likely than girls to have disorders of phenotypic heterogeneity (P<0.001), and mothers were more likely than fathers to transmit second-site copy-number variants to their offspring (P=0.02). CONCLUSIONS Multiple, large copy-number variants, including those of unknown pathogenic significance, compound to result in a severe clinical presentation, and secondary copy-number variants are preferentially transmitted from maternal carriers. (Funded by the Simons Foundation Autism Research Initiative and the National Institutes of Health.).
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Affiliation(s)
- Santhosh Girirajan
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA
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16
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Abstract
Disorders of sex development (DSD) are congenital conditions in which the development of chromosomal, gonadal, or anatomical sex is atypical. Many of the genes required for gonad development have been identified by analysis of DSD patients. However, the use of knockout and transgenic mouse strains have contributed enormously to the study of gonad gene function and interactions within the development network. Although the genetic basis of mammalian sex determination and differentiation has advanced considerably in recent years, a majority of 46,XY gonadal dysgenesis patients still cannot be provided with an accurate diagnosis. Some of these unexplained DSD cases may be due to mutations in novel DSD genes or genomic rearrangements affecting regulatory regions that lead to atypical gene expression. Here, we review our current knowledge of mammalian sex determination drawing on insights from human DSD patients and mouse models.
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Affiliation(s)
- Stefanie Eggers
- Murdoch Children’s Research Institute, Royal Children’s Hospital and Department of Paediatrics, The University of Melbourne, Melbourne, VIC Australia
| | - Andrew Sinclair
- Murdoch Children’s Research Institute, Royal Children’s Hospital and Department of Paediatrics, The University of Melbourne, Melbourne, VIC Australia
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17
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Affiliation(s)
- Heather C Mefford
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, WA 98195, USA.
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18
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Haemmerling S, Behnisch W, Doerks T, Korbel JO, Bork P, Moog U, Hentze S, Grasshoff U, Bonin M, Rieß O, Janssen JWG, Jauch A, Bartram CR, Reinhardt D, Koch KA, Bandapalli OR, Kulozik AE. A 15q24 microdeletion in transient myeloproliferative disease (TMD) and acute megakaryoblastic leukaemia (AMKL) implicates PML and SUMO3 in the leukaemogenesis of TMD/AMKL. Br J Haematol 2012; 157:180-7. [PMID: 22296450 DOI: 10.1111/j.1365-2141.2012.09028.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 11/21/2011] [Indexed: 11/29/2022]
Abstract
Transient myeloproliferative disorder (TMD) of the newborn and acute megakaryoblastic leukaemia (AMKL) in children with Down syndrome (DS) represent paradigmatic models of leukaemogenesis. Chromosome 21 gene dosage effects and truncating mutations of the X-chromosomal transcription factor GATA1 synergize to trigger TMD and AMKL in most patients. Here, we report the occurrence of TMD, which spontaneously remitted and later progressed to AMKL in a patient without DS but with a distinct dysmorphic syndrome. Genetic analysis of the leukaemic clone revealed somatic trisomy 21 and a truncating GATA1 mutation. The analysis of the patient's normal blood cell DNA on a genomic single nucleotide polymorphism (SNP) array revealed a de novo germ line 2·58 Mb 15q24 microdeletion including 41 known genes encompassing the tumour suppressor PML. Genomic context analysis of proteins encoded by genes that are included in the microdeletion, chromosome 21-encoded proteins and GATA1 suggests that the microdeletion may trigger leukaemogenesis by disturbing the balance of a hypothetical regulatory network of normal megakaryopoiesis involving PML, SUMO3 and GATA1. The 15q24 microdeletion may thus represent the first genetic hit to initiate leukaemogenesis and implicates PML and SUMO3 as novel components of the leukaemogenic network in TMD/AMKL.
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Affiliation(s)
- Susanne Haemmerling
- Department of Paediatric Oncology, Haematology and Immunology, University of Heidelberg Medical Centre, Heidelberg, Germany
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19
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Magoulas PL, El-Hattab AW. Chromosome 15q24 microdeletion syndrome. Orphanet J Rare Dis 2012; 7:2. [PMID: 22216833 PMCID: PMC3275445 DOI: 10.1186/1750-1172-7-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Accepted: 01/04/2012] [Indexed: 01/24/2023] Open
Abstract
Chromosome 15q24 microdeletion syndrome is a recently described rare microdeletion syndrome that has been reported in 19 individuals. It is characterized by growth retardation, intellectual disability, and distinct facial features including long face with high anterior hairline, hypertelorism, epicanthal folds, downslanting palpebral fissures, sparse and broad medial eyebrows, broad and/or depressed nasal bridge, small mouth, long smooth philtrum, and full lower lip. Other common findings include skeletal and digital abnormalities, genital abnormalities in males, hypotonia, behavior problems, recurrent infections, and eye problems. Other less frequent findings include hearing loss, growth hormone deficiency, hernias, and obesity. Congenital malformations, while rare, can be severe and include structural brain anomalies, cardiovascular malformations, congenital diaphragmatic hernia, intestinal atresia, imperforate anus, and myelomeningocele. Karyotypes are typically normal, and the deletions were detected in these individuals by array comparative genomic hybridization (aCGH). The deletions range in size from 1.7-6.1 Mb and usually result from nonallelic homologous recombination (NAHR) between paralogous low-copy repeats (LCRs). The majority of 15q24 deletions have breakpoints that localize to one of five LCR clusters labeled LCR15q24A, -B, -C, -D, and -E. The smallest region of overlap (SRO) spans a 1.2 Mb region between LCR15q24B to LCR15q24C. There are several candidate genes within the SRO, including CYP11A1, SEMA7A, CPLX3, ARID3B, STRA6, SIN3A and CSK, that may predispose to many of the clinical features observed in individuals with 15q24 deletion syndrome. The deletion occurred as a de novo event in all of the individuals when parents were available for testing. Parental aCGH and/or FISH studies are recommended to provide accurate genetic counseling and guidance regarding prognosis, recurrence risk, and reproductive options. Management involves a multi-disciplinary approach to care with the primary care physician and clinical geneticist playing a crucial role in providing appropriate screening, surveillance, and care for individuals with this syndrome. At the time of diagnosis, individuals should receive baseline echocardiograms, audiologic, ophthalmologic, and developmental assessments. Growth and feeding should be closely monitored. Other specialists that may be involved in the care of individuals with 15q24 deletion syndrome include immunology, endocrine, orthopedics, neurology, and urology. Chromosome 15q24 microdeletion syndrome should be differentiated from other genetic syndromes, particularly velo-cardio-facial syndrome (22q11.2 deletion syndrome), Prader-Willi syndrome, and Noonan syndrome. These conditions share some phenotypic similarity to 15q24 deletion syndrome yet have characteristic features specific to each of them that allows the clinician to distinguish between them. Molecular genetic testing and/or aCGH will be able to diagnose these conditions in the majority of individuals.
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Affiliation(s)
- Pilar L Magoulas
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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20
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Mefford HC, Rosenfeld JA, Shur N, Slavotinek AM, Cox VA, Hennekam RC, Firth HV, Willatt L, Wheeler P, Morrow EM, Cook J, Sullivan R, Oh A, McDonald MT, Zonana J, Keller K, Hannibal MC, Ball S, Kussmann J, Gorski J, Zelewski S, Banks V, Smith W, Smith R, Paull L, Rosenbaum KN, Amor DJ, Silva J, Lamb A, Eichler EE. Further clinical and molecular delineation of the 15q24 microdeletion syndrome. J Med Genet 2011; 49:110-8. [PMID: 22180641 PMCID: PMC3261729 DOI: 10.1136/jmedgenet-2011-100499] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Background Chromosome 15q24 microdeletion syndrome is a rare genomic disorder characterised by intellectual disability, growth retardation, unusual facial morphology and other anomalies. To date, 20 patients have been reported; 18 have had detailed breakpoint analysis. Aim To further delineate the features of the 15q24 microdeletion syndrome, the clinical and molecular characterisation of fifteen patients with deletions in the 15q24 region was performed, nearly doubling the number of reported patients. Methods Breakpoints were characterised using a custom, high-density array comparative hybridisation platform, and detailed phenotype information was collected for each patient. Results Nine distinct deletions with different breakpoints ranging in size from 266 kb to 3.75 Mb were identified. The majority of breakpoints lie within segmental duplication (SD) blocks. Low sequence identity and large intervals of unique sequence between SD blocks likely contribute to the rarity of 15q24 deletions, which occur 8–10 times less frequently than 1q21 or 15q13 microdeletions in our series. Two small, atypical deletions were identified within the region that help delineate the critical region for the core phenotype in the 15q24 microdeletion syndrome. Conclusion The molecular characterisation of these patients suggests that the core cognitive features of the 15q24 microdeletion syndrome, including developmental delays and severe speech problems, are largely due to deletion of genes in a 1.1–Mb critical region. However, genes just distal to the critical region also play an important role in cognition and in the development of characteristic facial features associated with 15q24 deletions. Clearly, deletions in the 15q24 region are variable in size and extent. Knowledge of the breakpoints and size of deletion combined with the natural history and medical problems of our patients provide insights that will inform management guidelines. Based on common phenotypic features, all patients with 15q24 microdeletions should receive a thorough neurodevelopmental evaluation, physical, occupational and speech therapies, and regular audiologic and ophthalmologic screening.
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Affiliation(s)
- Heather C Mefford
- Department of Pediatrics, Division of Genetic Medicine, University of Washington, Seattle, Washington, DC 98195, USA.
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21
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Narumi Y, Shiohara M, Wakui K, Hama A, Kojima S, Yoshikawa K, Amano Y, Kosho T, Fukushima Y. Myelodysplastic syndrome in a child with 15q24 deletion syndrome. Am J Med Genet A 2011; 158A:412-6. [PMID: 22140075 DOI: 10.1002/ajmg.a.34395] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2011] [Accepted: 10/24/2011] [Indexed: 11/10/2022]
Abstract
15q24 deletion syndrome is a recently-described chromosomal disorder, characterized by developmental delay, growth deficiency, distinct facial features, digital abnormalities, loose connective tissue, and genital malformations in males. To date, 19 patients have been reported. We report on a 13-year-old boy with this syndrome manifesting childhood myelodysplastic syndrome (MDS). He had characteristic facial features, hypospadias, and mild developmental delay. He showed neutropenia and thrombocytopenia for several years. At age 13 years, bone marrow examination was performed, which showed a sign suggestive of childhood MDS: mild dysplasia in the myeloid, erythroid, and megakaryocytic cell lineages. Array comparative genomic hybridization (array CGH) revealed a de novo 3.4 Mb 15q24.1q24.3 deletion. Although MDS has not been described in patients with the syndrome, a boy was reported to have acute lymphoblastic leukemia (ALL). The development of MDS and hematological malignancy in the syndrome might be caused by the haploinsufficiency of deleted 15q24 segment either alone or in combination with other genetic abnormalities in hematopoietic cells. Further hematological investigation is recommended to be beneficial if physical and hematological examination results are suggestive of hematopoietic disturbance in patients with the syndrome.
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Affiliation(s)
- Yoko Narumi
- Department of Medical Genetics, Shinshu University School of Medicine, Matsumoto, Japan.
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22
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Deak KL, Horn SR, Rehder CW. The evolving picture of microdeletion/microduplication syndromes in the age of microarray analysis: variable expressivity and genomic complexity. Clin Lab Med 2011; 31:543-64, viii. [PMID: 22118736 DOI: 10.1016/j.cll.2011.08.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several new microdeletion and microduplication syndromes have been discovered in a genotype-first approach. Many of these disorders are caused by nonallelic homologous recombination between blocks of segmental duplication. The authors describe 9 regions for which copy number alteration is proposed to cause an abnormal phenotype. Some of these disorders have been observed in affected individuals and individuals lacking a clearly abnormal phenotype. These deletions and duplications are thought to be contributory, but not always sufficient, to elicit an abnormal outcome. Additional studies are necessary to further evaluate the penetrance and delineate the clinical spectrum associated with many of these newly described disorders.
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Affiliation(s)
- Kristen L Deak
- Department of Pathology, Duke University, Durham, NC, USA
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23
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L Ng IS, Chin WH, P Lim EC, Tan EC. An additional case of the recurrent 15q24.1 microdeletion syndrome and review of the literature. Twin Res Hum Genet 2011; 14:333-9. [PMID: 21787116 DOI: 10.1375/twin.14.4.333] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We report a 9-year-old girl with 3 Mb interstitial deletion of chromosome 15q24 identified by oligonucleotide array comparative hybridization. She is of Chinese ancestry and shared some typical features of previously reported 15q24 deletion cases such as mild dysmorphism with developmental and speech delay. She also had mild hearing loss that was reported in one other case. We compared all 19 cases that are identified from array-CGH. The deletion occurred within an 8.3 Mb region from 15q23 to 15q24.3. The minimum overlapping deleted region is less than 0.5 Mb from 72.3 Mb to 72.7 Mb. The functions of the nine annotated genes within the region and how they might contribute to the microdeletion phenotype are discussed.
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Affiliation(s)
- Ivy S L Ng
- Genetics Service, KK Women's and Children's Hospital, Singapore
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24
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Cukier HN, Salyakina D, Blankstein SF, Robinson JL, Sacharow S, Ma D, Wright HH, Abramson RK, Menon R, Williams SM, Haines JL, Cuccaro ML, Gilbert JR, Pericak-Vance MA. Microduplications in an autism multiplex family narrow the region of susceptibility for developmental disorders on 15q24 and implicate 7p21. Am J Med Genet B Neuropsychiatr Genet 2011; 156B:493-501. [PMID: 21480499 PMCID: PMC5490366 DOI: 10.1002/ajmg.b.31188] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 03/04/2011] [Indexed: 11/08/2022]
Abstract
Copy number variations (CNVs) play a crucial role in the intricate genetics of autism spectrum disorders. A region on chromosome 15q24 vulnerable to both deletions and duplications has been previously implicated in a range of phenotypes including autism, Asperger's syndrome, delayed development, and mild to severe mental retardation. Prior studies have delineated a minimal critical region of approximately 1.33 Mb. In this study, a multiplex autism family was evaluated for CNVs using genotyping data from the Illumina 1 M BeadChip and analyzed with the PennCNV algorithm. Variants were then identified that co-segregate with autism features in this family. Here, we report autistic first cousins who carry two microduplications concordant with disease. Both duplications were inherited maternally and found to be identical by descent. The first is an approximately 10,000 base pair microduplication within the minimal region on 15q24 that falls across a single gene, ubiquitin-like 7. This is the smallest duplication in the region to result in a neuropsychiatric disorder, potentially narrowing the critical region for susceptibility to developmental and autism spectrum disorders. The second is a novel, 352 kb tandem duplication on 7p21 that replicates part of the neurexophilin 1 and islet cell autoantigen 1 genes. The breakpoint junction falls within the intronic regions of these genes and demonstrates a microhomology of four base pairs. Each of these microduplications may contribute to the complex etiology of autism spectrum disorders.
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Affiliation(s)
- Holly N. Cukier
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida
| | - Daria Salyakina
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida
| | - Sarah F. Blankstein
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida
| | - Joycelyn L. Robinson
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida
| | - Stephanie Sacharow
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida,Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida
| | - Deqiong Ma
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida,Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida
| | - Harry H. Wright
- Department of Neuropsychiatry, University of South Carolina School of Medicine, Columbia, South Carolina
| | - Ruth K. Abramson
- Department of Neuropsychiatry, University of South Carolina School of Medicine, Columbia, South Carolina
| | - Ramkumar Menon
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, Georgia,Department of Obstetrics and Gynecology, Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Scott M. Williams
- Center for Human Genetics Research, Vanderbilt University, Nashville, Tennessee
| | - Jonathan L. Haines
- Center for Human Genetics Research, Vanderbilt University, Nashville, Tennessee
| | - Michael L. Cuccaro
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida,Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida
| | - John R. Gilbert
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida,Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida
| | - Margaret A. Pericak-Vance
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, Florida,Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida,Correspondence to: Margaret A. Pericak-Vance, Ph.D., Associate Dean for Human Genomic Programs, Dr. John T. Macdonald Foundation Professor of Human Genomics, Director, John P. Hussman Institute for Human Genomics, 1501 NW 10th Avenue, BRB-314 (M860), University of Miami, Miller School of Medicine, Miami, FL 33136.
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25
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Roetzer KM, Schwarzbraun T, Obenauf AC, Hauser E, Speicher MR. Further evidence for the pathogenicity of 15q24 microduplications distal to the minimal critical regions. Am J Med Genet A 2011; 152A:3173-8. [PMID: 21108404 DOI: 10.1002/ajmg.a.33750] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
DNA copy number alterations in 15q24 have repeatedly been reported in patients exhibiting mild to moderate developmental delay and dysmorphic features. To date, mainly microdeletions have been described, and comparison of overlapping regions allowed the definition of minimal critical regions (MCRs) for microdeletions as well as microduplications. These MCRs are associated with distinct phenotypes. Recently, a family with a new microduplication distal to these MCRs was reported. However, for this alteration the typical phenotypical consequences could not yet be determined. Here we present another family with a nearly identical microduplication exhibiting a broad clinical spectrum including developmental delay, autistic traits and dysmorphic features. Our data suggest that microduplications adjacent and distal to the known MCRs are variable in expressivity and are associated with distinct features. They might represent a novel and recurrent microduplication syndrome.
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26
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Girirajan S, Eichler EE. Phenotypic variability and genetic susceptibility to genomic disorders. Hum Mol Genet 2010; 19:R176-87. [PMID: 20807775 PMCID: PMC2953748 DOI: 10.1093/hmg/ddq366] [Citation(s) in RCA: 197] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 07/28/2010] [Accepted: 08/24/2010] [Indexed: 11/13/2022] Open
Abstract
The duplication architecture of the human genome predisposes our species to recurrent copy number variation and disease. Emerging data suggest that this mechanism of mutation contributes to both common and rare diseases. Two features regarding this form of mutation have emerged. First, common structural polymorphisms create susceptible and protective chromosomal architectures. These structural polymorphisms occur at varying frequencies in populations, leading to different susceptibility and ethnic predilection. Second, a subset of rearrangements shows extreme variability in expressivity. We propose that two types of genomic disorders may be distinguished: syndromic forms where the phenotypic features are largely invariant and those where the same molecular lesion associates with a diverse set of diagnoses including epilepsy, schizophrenia, autism, intellectual disability and congenital malformations. Copy number variation analyses of patient genomes reveal that disease type and severity may be explained by the occurrence of additional rare events and their inheritance within families. We propose that the overall burden of copy number variants creates differing sensitized backgrounds during development leading to different thresholds and disease outcomes. We suggest that the accumulation of multiple high-penetrant alleles of low frequency may serve as a more general model for complex genetic diseases, posing a significant challenge for diagnostics and disease management.
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Affiliation(s)
| | - Evan E. Eichler
- Department of Genome Sciences, Howard Hughes Medical Institute,University of Washington School of Medicine, PO Box 355065, Foege S413C, 3720 15th Avenue NE, Seattle, WA 98195, USA
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27
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Deletion and duplication of 15q24: Molecular mechanisms and potential modification by additional copy number variants. Genet Med 2010; 12:573-86. [DOI: 10.1097/gim.0b013e3181eb9b4a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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28
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Bashamboo A, Ledig S, Wieacker P, Achermann JC, Achermann J, McElreavey K. New technologies for the identification of novel genetic markers of disorders of sex development (DSD). Sex Dev 2010; 4:213-24. [PMID: 20820110 PMCID: PMC2948663 DOI: 10.1159/000314917] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Although the genetic basis of human sexual determination and differentiation has advanced considerably in recent years, the fact remains that in most subjects with disorders of sex development (DSD) the underlying genetic cause is unknown. Where pathogenic mutations have been identified, the phenotype can be highly variable, even within families, suggesting that other genetic variants are influencing the expression of the phenotype. This situation is likely to change, as more powerful and affordable tools become widely available for detailed genetic analyses. Here, we describe recent advances in comparative genomic hybridisation, sequencing by hybridisation and next generation sequencing, and we describe how these technologies will have an impact on our understanding of the genetic causes of DSD.
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Affiliation(s)
- A Bashamboo
- Human Developmental Genetics Unit, Institut Pasteur, Paris, France
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