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Dai L, Zhang D, Wu Z, Guan X, Ma M, Li L, Zhang Y, Bai Y, Guo H. A Tiered Genetic Screening Strategy for the Molecular Diagnosis of Intellectual Disability in Chinese Patients. Front Genet 2021; 12:669217. [PMID: 34630504 PMCID: PMC8495063 DOI: 10.3389/fgene.2021.669217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 09/10/2021] [Indexed: 01/02/2023] Open
Abstract
Objective: Intellectual disability (ID) is one of the most common developmental disabilities. To identify the genetic etiology of IDs in Chongqing, we conducted a multistage study in Chinese Han patients. Methods: We collected the clinical and etiological data of 1665 ID patients, including 1,604 from the disabled children evaluation center and 61 from the pediatric rehabilitation unit. Routine genetic screening results were obtained, including karyotype and candidate gene analysis. Then 105 idiopathic cases with syndromic and severe ID/developmental delay (DD) were selected and tested by chromosomal microarray (CMA) and whole exome sequencing (WES) sequentially. The pathogenicity of the CNVs and SNVs were evaluated according to ACMG guidelines. Results: Molecular diagnosis was made by routine genetic screening in 216 patients, including 196 chromosomal syndromes. Among the 105 idiopathic patients, 49 patients with pathogenic/likely pathogenic CNVs and 21 patients with VUS were identified by CMA. Twenty-six pathogenic CNVs underlying well-known syndromic cases, such as Williams-Beuren syndrome, were confirmed by multiplex ligation-dependent probe amplification (MLPA). Nine novel mutations were identified by WES in thirty-fix CNV-negative ID cases. Conclusions: The study illustrated the genetic aberrations distribution of a large ID cohort in Chongqing. Compared with conventional or single methods, a tiered high-throughput diagnostic strategy was developed to greatly improve the diagnostic yields and extend the variation spectrum for idiopathic syndromic ID cases.
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Affiliation(s)
- Limeng Dai
- Department of Medical Genetics, College of Basic Medical Science, Army Medical University, Chongqing, China
| | - Danyan Zhang
- Department of Medical Genetics, College of Basic Medical Science, Army Medical University, Chongqing, China.,Chongqing Population and Family Planning Science and Technology Research Institute/NHC Key Laboratory of Birth Defects and Reproductive Health, Chongqing, China
| | - Zhifeng Wu
- Department of Pediatrics, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Xingying Guan
- Department of Medical Genetics, College of Basic Medical Science, Army Medical University, Chongqing, China
| | - Mingfu Ma
- Chongqing Population and Family Planning Science and Technology Research Institute/NHC Key Laboratory of Birth Defects and Reproductive Health, Chongqing, China
| | - Lianbing Li
- Chongqing Population and Family Planning Science and Technology Research Institute/NHC Key Laboratory of Birth Defects and Reproductive Health, Chongqing, China
| | - Yuping Zhang
- Department of Pediatrics, Xinqiao Hospital, Army Medical University, Chongqing, China
| | - Yun Bai
- Department of Medical Genetics, College of Basic Medical Science, Army Medical University, Chongqing, China
| | - Hong Guo
- Department of Medical Genetics, College of Basic Medical Science, Army Medical University, Chongqing, China
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Ozantürk A, Davis EE, Sabo A, Weiss MM, Muzny D, Dugan-Perez S, Sistermans EA, Gibbs RA, Özgül KR, Yalnızoglu D, Serdaroglu E, Dursun A, Katsanis N. A t(5;16) translocation is the likely driver of a syndrome with ambiguous genitalia, facial dysmorphism, intellectual disability, and speech delay. Cold Spring Harb Mol Case Stud 2016; 2:a000703. [PMID: 27148584 PMCID: PMC4849851 DOI: 10.1101/mcs.a000703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Genetic studies grounded on monogenic paradigms have accelerated both gene discovery and molecular diagnosis. At the same time, complex genomic rearrangements are also appreciated as potent drivers of disease pathology. Here, we report two male siblings with a dysmorphic face, ambiguous genitalia, intellectual disability, and speech delay. Through quad-based whole-exome sequencing and concomitant molecular cytogenetic testing, we identified two copy-number variants (CNVs) in both affected individuals likely arising from a balanced translocation: a 13.5-Mb duplication on Chromosome 16 (16q23.1 → 16qter) and a 7.7-Mb deletion on Chromosome 5 (5p15.31 → 5pter), as well as a hemizygous missense variant in CXorf36 (also known as DIA1R). The 5p terminal deletion has been associated previously with speech delay, whereas craniofacial dysmorphia and genital/urinary anomalies have been reported in patients with a terminal duplication of 16q. However, dosage changes in either genomic region alone could not account for the overall clinical presentation in our family; functional testing of CXorf36 in zebrafish did not induce defects in neurogenesis or the craniofacial skeleton. Notably, literature and database analysis revealed a similar dosage disruption in two siblings with extensive phenotypic overlap with our patients. Taken together, our data suggest that dosage perturbation of genes within the two chromosomal regions likely drives the syndromic manifestations of our patients and highlight how multiple genetic lesions can contribute to complex clinical pathologies.
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Affiliation(s)
- Ayşegül Ozantürk
- Department of Pediatrics, Metabolism Unit, Hacettepe University, Ankara 06410, Turkey;; Department of Biology, Molecular Biology Section, Hacettepe University, Ankara 06800, Turkey;; Center for Human Disease Modeling, Duke University, Durham, North Carolina 27701, USA
| | - Erica E Davis
- Center for Human Disease Modeling, Duke University, Durham, North Carolina 27701, USA
| | - Aniko Sabo
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Marjan M Weiss
- Department of Clinical Genetics, VU University Medical Center (Amsterdam), NL-1081 HV Amsterdam, The Netherlands
| | - Donna Muzny
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Shannon Dugan-Perez
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Erik A Sistermans
- Department of Clinical Genetics, VU University Medical Center (Amsterdam), NL-1081 HV Amsterdam, The Netherlands
| | - Richard A Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Köksal R Özgül
- Department of Pediatrics, Metabolism Unit, Hacettepe University, Ankara 06410, Turkey
| | - Dilek Yalnızoglu
- Department of Pediatrics, Pediatric Neurology Unit, Hacettepe University, Ankara 06410, Turkey
| | - Esra Serdaroglu
- Department of Pediatrics, Pediatric Neurology Unit, Hacettepe University, Ankara 06410, Turkey
| | - Ali Dursun
- Department of Pediatrics, Metabolism Unit, Hacettepe University, Ankara 06410, Turkey
| | - Nicholas Katsanis
- Center for Human Disease Modeling, Duke University, Durham, North Carolina 27701, USA
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