1
|
Tyagi R, Kumar S, Dalal A, Mohammed F, Mohanty M, Kaur P, Anand A. Repurposing Pathogenic Variants of DMD Gene and its Isoforms for DMD Exon Skipping Intervention. Curr Genomics 2020; 20:519-530. [PMID: 32655290 PMCID: PMC7327972 DOI: 10.2174/1389202920666191107142754] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Background
Duchenne Muscular Dystrophy (DMD) is a progressive, fatal neuromuscular disorder caused by mutations in the DMD gene. Emerging antisense oligomer based exon skipping therapy provides hope for the restoration of the reading frame. Objectives
Population-based DMD mutation database may enable exon skipping to be used for the benefit of patients. Hence, we planned this study to identify DMD gene variants in North Indian DMD cases. Methods
A total of 100 DMD cases were recruited and Multiplex ligation-dependent probe amplification (MLPA) analysis was performed to obtain the deletion and duplication profile. Results
Copy number variations (deletion/duplication) were found in 80.85% of unrelated DMD cases. Sixty-eight percent of cases were found to have variations in the distal hotspot region (Exon 45-55) of the DMD gene. Exon 44/45 variations were found to be the most prominent among single exon variations, whereas exon 49/50 was found to be the most frequently mutated locations in single/multiple exon variations. As per Leiden databases, 86.84% cases harboured out-of-frame mutations. Domain wise investigation revealed that 68% of mutations were localized in the region of spectrin repeats. Dp140 isoform was predicted to be absent in 62/76 (81.57%) cases. A total of 45/80 (56.25%) and 23/80 (28.70%) DMD subjects were predicted to be amenable to exon 51 and exon 45 skipping trials, respectively. Conclusion
A major proportion of DMD subjects (80%) could be diagnosed by the MLPA technique. The data generated from our study may be beneficial for strengthening of mutation database in the North Indian population.
Collapse
Affiliation(s)
- Rahul Tyagi
- 1Neuroscience Research Lab, Department of Neurology, Postgraduate Institute of Medical Education and Research, Chandigarh, India; 2Diagnostics Division, Center for DNA fingerprinting and Diagnostics, Hyderabad, India; 3Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology, New Delhi, India; 4Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Sumit Kumar
- 1Neuroscience Research Lab, Department of Neurology, Postgraduate Institute of Medical Education and Research, Chandigarh, India; 2Diagnostics Division, Center for DNA fingerprinting and Diagnostics, Hyderabad, India; 3Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology, New Delhi, India; 4Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Ashwin Dalal
- 1Neuroscience Research Lab, Department of Neurology, Postgraduate Institute of Medical Education and Research, Chandigarh, India; 2Diagnostics Division, Center for DNA fingerprinting and Diagnostics, Hyderabad, India; 3Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology, New Delhi, India; 4Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Faruq Mohammed
- 1Neuroscience Research Lab, Department of Neurology, Postgraduate Institute of Medical Education and Research, Chandigarh, India; 2Diagnostics Division, Center for DNA fingerprinting and Diagnostics, Hyderabad, India; 3Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology, New Delhi, India; 4Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Manju Mohanty
- 1Neuroscience Research Lab, Department of Neurology, Postgraduate Institute of Medical Education and Research, Chandigarh, India; 2Diagnostics Division, Center for DNA fingerprinting and Diagnostics, Hyderabad, India; 3Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology, New Delhi, India; 4Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Paramvir Kaur
- 1Neuroscience Research Lab, Department of Neurology, Postgraduate Institute of Medical Education and Research, Chandigarh, India; 2Diagnostics Division, Center for DNA fingerprinting and Diagnostics, Hyderabad, India; 3Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology, New Delhi, India; 4Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Akshay Anand
- 1Neuroscience Research Lab, Department of Neurology, Postgraduate Institute of Medical Education and Research, Chandigarh, India; 2Diagnostics Division, Center for DNA fingerprinting and Diagnostics, Hyderabad, India; 3Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology, New Delhi, India; 4Department of Neurosurgery, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| |
Collapse
|
2
|
Zhu YB, Luo JW, Jiang F, Liu G. Genetic analysis of sick sinus syndrome in a family harboring compound CACNA1C and TTN mutations. Mol Med Rep 2018; 17:7073-7080. [PMID: 29568937 PMCID: PMC5928663 DOI: 10.3892/mmr.2018.8773] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 03/06/2018] [Indexed: 12/23/2022] Open
Abstract
Sick sinus syndrome (SSS) is a sinus node dysfunction characterized by severe sinus bradycardia. SSS results in insufficient blood supply to the brain, heart, kidneys, and other organs and is associated with the increased risk of sudden cardiac death. Bradyarrhythmia appears in the absence of any associated cardiac pathology and displays a genetic legacy. The present study identified a family with primary manifestation of sinus bradycardia (five individuals) along with early repolarization (four individuals) and atrial fibrillation (one individual). Targeted exome sequencing was used to screen exons and adjacent splice sites of 61 inherited arrhythmia‑associated genes, to detect pathogenic genes and variant sites in the proband. Family members were sequenced by Sanger sequencing and protein functions predicted by Polyphen‑2 software. A total of three rare variants were identified in the family, including two missense variants in calcium voltage‑gated channel subunit alpha1 C (CACNA1C) (gi:193788541, NM_001129843), c.1786G>A (p.V596M) and c.5344G>A (p.A1782T), and one missense variant in titin (TTN) c.49415G>A (p.R16472H) (gi:291045222, NM_003319). The variants p.V596M and p.R16472H were predicted to be deleterious and resulted in alterations in the amino acid type and sequence of the polypeptide chain, which may partially or completely inactivate the encoded protein. The comparison of literature, gene database, and pedigree phenotype analysis suggests that p.V596M or p.R16472H variants are pathogenic. The complex overlapping variants at three loci lead to a more severe phenotype in the proband, and may increase the susceptibility of individuals to atrial fibrillation. The simultaneous occurrence of V596M and R16472H may increase the severity of early repolarization. Various family members may have carried heterozygous mutants of p.A1782T and p.R16472H due to genetic heterogeneity, however did not exhibit clinical signs of cardiac electrophysiological alterations, potentially attributable to the low vagal tone. To the best of the author's knowledge, this is the first study to suggest the involvement of the novel missense CACNA1C c.1786G>A and TTN c.49415G>A variants in the inheritance of symptomatic bradycardia and development of SSS.
Collapse
Affiliation(s)
- Yao-Bin Zhu
- Department of Traditional Chinese Medicine, The First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Jie-Wei Luo
- Provincial Clinical Medical College, Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Fen Jiang
- Pharmacogenomics Research Center, Inje University College of Medicine, Busan 614‑715, Republic of Korea
| | - Gui Liu
- Department of Traditional Chinese Medicine, Fujian Provincial Hospital, Fuzhou, Fujian 350001, P.R. China
| |
Collapse
|