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Zhang L, Lou H, Huang Y, Dong L, Gong X, Zhang X, Bao W, Xiao R. Identification of Synonymous Pathogenic Variants in Monogenic Disorders by Integrating Exome with Transcriptome Sequencing. J Mol Diagn 2024; 26:267-277. [PMID: 38280421 DOI: 10.1016/j.jmoldx.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 11/23/2023] [Accepted: 12/20/2023] [Indexed: 01/29/2024] Open
Abstract
Exome sequencing is becoming a first-tier clinical diagnostic test for Mendelian diseases, drastically reducing the time and cost of diagnostic odyssey and improving the diagnosis rate. Despite its success, exome sequencing faces practical challenges in assessing the pathogenicity of numerous intronic and synonymous variants, leaving a significant proportion of patients undiagnosed. In this study, a whole-blood transcriptome database was constructed that showed the expression profile of 2981 Online Mendelian Inheritance in Man disease genes in blood samples. Meanwhile, a workflow integrating exome sequencing, blood transcriptome sequencing, and in silico prediction tools to identify and validate splicing-altering intronic or synonymous variants was proposed. Following this pipeline, seven synonymous variants in eight patients were discovered. Of these, the functional evidence of c.981G>A (PIGN), c.1161A>G (ALPL), c.858G>A (ATP6AP2), and c.1011G>T (MTHFR) have not been reported previously. RNA sequencing validation confirmed that these variants induced aberrant splicing, expanding the disease-causing variant spectrum of these genes. Overall, this study shows the feasibility of combining multi-omics data to identify splicing-altering variants, especially the power of RNA sequencing. It also reveals that synonymous variants, which often are overlooked in standard diagnostic approaches, comprise an important portion of unresolved genetic diseases.
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Affiliation(s)
- Lin Zhang
- Prenatal Diagnosis Center, Peking University People's Hospital, Beijing, China.
| | | | - Yanhong Huang
- Prenatal Diagnosis Center, Liaocheng Maternal and Child Health Care Hospital, Liaocheng, China
| | - Liping Dong
- Newborn Screening Center, Zibo Maternal and Child Health Care Hospital, Zibo, China
| | - Xueye Gong
- Department of Medical Genetics and Prenatal Diagnosis, Binzhou Maternal and Child Health Care Hospital, Binzhou, China
| | - Xiaoning Zhang
- Department of the Clinical Laboratory, Binzhou Maternal and Child Health Care Hospital, Binzhou, China
| | - Wenqi Bao
- Becreative Lab Co., Ltd., Beijing, China
| | - Rui Xiao
- National Engineering Laboratory for Key Technology of Birth Defect Control and Prevention, Screening and Diagnostic R&D Center, Hangzhou, China
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Bertani-Torres W, Lezirovitz K, Alencar-Coutinho D, Pardono E, da Costa SS, Antunes LDN, de Oliveira J, Otto PA, Pingault V, Mingroni-Netto RC. Waardenburg Syndrome: The Contribution of Next-Generation Sequencing to the Identification of Novel Causative Variants. Audiol Res 2023; 14:9-25. [PMID: 38391765 PMCID: PMC10886116 DOI: 10.3390/audiolres14010002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 12/08/2023] [Accepted: 12/13/2023] [Indexed: 02/24/2024] Open
Abstract
Waardenburg syndrome (WS) is characterized by hearing loss and pigmentary abnormalities of the eyes, hair, and skin. The condition is genetically heterogeneous, and is classified into four clinical types differentiated by the presence of dystopia canthorum in type 1 and its absence in type 2. Additionally, limb musculoskeletal abnormalities and Hirschsprung disease differentiate types 3 and 4, respectively. Genes PAX3, MITF, SOX10, KITLG, EDNRB, and EDN3 are already known to be associated with WS. In WS, a certain degree of molecularly undetected patients remains, especially in type 2. This study aims to pinpoint causative variants using different NGS approaches in a cohort of 26 Brazilian probands with possible/probable diagnosis of WS1 (8) or WS2 (18). DNA from the patients was first analyzed by exome sequencing. Seven of these families were submitted to trio analysis. For inconclusive cases, we applied a targeted NGS panel targeting WS/neurocristopathies genes. Causative variants were detected in 20 of the 26 probands analyzed, these being five in PAX3, eight in MITF, two in SOX10, four in EDNRB, and one in ACTG1 (type 2 Baraitser-Winter syndrome, BWS2). In conclusion, in our cohort of patients, the detection rate of the causative variant was 77%, confirming the superior detection power of NGS in genetically heterogeneous diseases.
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Affiliation(s)
- William Bertani-Torres
- Centro de Estudos sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, Brazil
- Department of Embryology and Genetics of Malformations, INSERM (Institut National de la Santé et de la Recherche Médicale) UMR (Unité Mixte de Recherche) 1163, Université Paris-Cité and Institut Imagine, 75015 Paris, France
| | - Karina Lezirovitz
- Otorhinolaryngology Lab-LIM 32, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo 01246-000, Brazil
| | - Danillo Alencar-Coutinho
- Otorhinolaryngology Lab-LIM 32, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo 01246-000, Brazil
| | - Eliete Pardono
- Instituto de Ciências da Saúde, Universidade Paulista UNIP, São Paulo 04026-002, Brazil
- Colégio Miguel de Cervantes, São Paulo 05618-001, Brazil
| | - Silvia Souza da Costa
- Centro de Estudos sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, Brazil
| | - Larissa do Nascimento Antunes
- Centro de Estudos sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, Brazil
| | - Judite de Oliveira
- Médecine Génomique des Maladies Rares, AP-HP, Hôpital Necker-Enfants Malades, 75015 Paris, France
| | - Paulo Alberto Otto
- Centro de Estudos sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, Brazil
| | - Véronique Pingault
- Department of Embryology and Genetics of Malformations, INSERM (Institut National de la Santé et de la Recherche Médicale) UMR (Unité Mixte de Recherche) 1163, Université Paris-Cité and Institut Imagine, 75015 Paris, France
- Médecine Génomique des Maladies Rares, AP-HP, Hôpital Necker-Enfants Malades, 75015 Paris, France
| | - Regina Célia Mingroni-Netto
- Centro de Estudos sobre o Genoma Humano e Células Tronco, Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo 05508-090, Brazil
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Sarkar A, Panati K, Narala VR. Code inside the codon: The role of synonymous mutations in regulating splicing machinery and its impact on disease. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2022; 790:108444. [PMID: 36307006 DOI: 10.1016/j.mrrev.2022.108444] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 10/10/2022] [Accepted: 10/21/2022] [Indexed: 11/06/2022]
Abstract
In eukaryotes, precise pre-mRNA processing, including alternative splicing, is essential to carry out the intricate protein translation process. Both point mutations (that alter the translated protein sequence) and synonymous mutations (that do not alter the translated protein sequence) are capable of affecting the splicing process. Synonymous mutations are known to affect gene expression via altering mRNA stability, mRNA secondary structure, splicing processes, and translational kinetics. In higher eukaryotes, precise splicing is regulated by three weakly conserved cis-elements, 5' and 3' splice sites and the branch site. Many other cis-acting elements (exonic/intronic splicing enhancers and silencers) and trans-acting splicing factors (serine and arginine-rich proteins and heterogeneous nuclear ribonucleoproteins) have also been found to enhance or suppress the splicing process. The appearance of synonymous mutations in cis-acting elements can alter the splicing process by changing the binding pattern of splicing factors to exonic splicing enhancers or silencer motifs. This results in exon skipping, intron retention, and various other forms of alternative splicing, eventually leading to the emergence of a wide range of diseases. The focus of this review is to elucidate the role of synonymous mutations and their impact on abnormal splicing mechanisms. Further, this study highlights the function of synonymous mutation in mediating abnormal splicing in cancer and development of X-linked, and autosomal inherited diseases.
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Affiliation(s)
- Avik Sarkar
- Department of Zoology, Vidyasagar University, Midnapore, West Bengal 721102, India
| | - Kalpana Panati
- Department of Biotechnology, Government College for Men, Kadapa 516004, India
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Wang G, Li X, Gao X, Su Y, Han M, Gao B, Guo C, Kang D, Huang S, Yuan Y, Dai P. Analysis of genotype-phenotype relationships in 90 Chinese probands with Waardenburg syndrome. Hum Genet 2021; 141:839-852. [PMID: 34142234 DOI: 10.1007/s00439-021-02301-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/08/2021] [Indexed: 12/31/2022]
Abstract
Waardenburg syndrome (WS) is a phenotypically and genetically heterogeneous disorder characterised by hearing loss and pigmentary abnormalities. We clarified the clinical and genetic features in 90 Chinese WS probands. Disease-causing variants were detected in 55 probands, for a molecular diagnosis rate of 61%, including cases related to PAX3 (14.4%), MITF (24.4%), and SOX10 (22.2%). Altogether, 48 variants were identified, including 44 single-nucleotide variants and 4 copy number variants. By parental genotyping, de novo variants were observed in 60% of probands and 15.4% of the de novo variation was associated with mosaicism. Statistical analyses revealed that brown freckles on the skin were more frequently seen in probands with MITF variants; patchy depigmented skin, asymmetric hearing loss, and white forelocks occurred more often in cases with PAX3 variants; and congenital inner ear malformations were more common and cochlear hypoplasia III was exclusively observed in those with SOX10 variants. In addition, we found that ranges of W-index values overlapped between WS probands with different genetic variants, and the use of the W-index as a tool for assessing dystopia canthorum may be problematic in Chinese. Herein, we report the spectrum of a cohort of WS probands and elucidate the relationship between genotype and phenotype.
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Affiliation(s)
- Guojian Wang
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Xiaohong Li
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China.,Department of Otorhinolaryngology Head and Neck Surgery, National Center for Children's Health, Beijing Children's Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory for Pediatric, Diseases of Otolaryngology-Head and Neck Surgery, Beijing, China
| | - Xue Gao
- Department of Otolaryngology, PLA Rocket Force Characteristic Medical Center, Beijing, China
| | - Yu Su
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Mingyu Han
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Bo Gao
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Chang Guo
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Dongyang Kang
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Shasha Huang
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China.
| | - Yongyi Yuan
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China.
| | - Pu Dai
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China.
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Wang L, Qin L, Li T, Liu H, Ma L, Li W, Wu D, Wang H, Guo Q, Guo L, Liao S. Prenatal diagnosis and genetic counseling for Waardenburg syndrome type I and II in Chinese families. Mol Med Rep 2017; 17:172-178. [PMID: 29115496 PMCID: PMC5780116 DOI: 10.3892/mmr.2017.7874] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 06/14/2017] [Indexed: 01/13/2023] Open
Abstract
Waardenburg syndrome (WS) is an auditory-pigmentary disorder with varying combinations of sensorineural hearing loss and abnormal pigmentation. The present study aimed to investigate the underlying molecular pathology and provide a method of prenatal diagnosis of WS in Chinese families. A total of 11 patients with WS from five unrelated Chinese families were enrolled. A thorough clinical examination was performed on all participants. Furthermore, patients with WS underwent screening for mutations in the following genes: Paired box 3 (PAX3), melanogenesis associated transcription factor (MITF), SRY-box 10, snail family transcriptional repressor 2 and endothelin receptor type B using polymerase chain reaction sequencing. Array-based comparative genomic hybridization was used for specific patients whose sequence results were normal. Following identification of the genotype of the probands and their parents, prenatal genetic diagnosis was performed for family 01 and 05. According to the diagnostic criteria for WS, five cases were diagnosed as WS1, while the other six cases were WS2. Genetic analysis revealed three mutations, including a nonsense mutation PAX3 c.583C>T in family 01, a splice-site mutation MITF c.909G>A in family 03 and an in-frame deletion MITF c.649_651delGAA in family 05. To the best of the authors' knowledge the mutations (c.583C>T in PAX3 and c.909G>A in MITF) were reported for the first time in Chinese people. Mutations in the gene of interest were not identified in family 02 and 04. The prenatal genetic testing of the two fetuses was carried out and demonstrated that the two babies were normal. The results of the present study expanded the range of known genetic mutations in China. Identification of genetic mutations in these families provided an efficient way to understand the causes of WS and improved genetic counseling.
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Affiliation(s)
- Li Wang
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Litao Qin
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Tao Li
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Hongjian Liu
- Department of Otorhinolaryngology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Lingcao Ma
- Department of Otorhinolaryngology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Wan Li
- Department of Otorhinolaryngology, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Dong Wu
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Hongdan Wang
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Qiannan Guo
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Liangjie Guo
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
| | - Shixiu Liao
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan 450003, P.R. China
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