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Biswas A, Raza A, Das S, Kapoor M, Jayarajan R, Verma A, Shamsudheen KV, Murry B, Seth S, Bhargava B, Scaria V, Sivasubbu S, Rao VR. Loss of function mutation in the P2X7, a ligand-gated ion channel gene associated with hypertrophic cardiomyopathy. Purinergic Signal 2019; 15:205-210. [PMID: 31152337 DOI: 10.1007/s11302-019-09660-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Accepted: 05/16/2019] [Indexed: 12/21/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is an inherited heart failure condition, mostly found to have genetic abnormalities, and is a leading cause of sudden death in young adults. Whole exome sequencing should be given consideration as a molecular diagnostic tool to identify disease-causing mutation/s. In this study, a HCM family with multiple affected members having history of sudden death were subjected to exome sequencing along with unaffected members. Quality passed variants obtained were filtered for rarity (MAF > 0.5%), evolutionary conservation, pathogenic prediction, and segregation in affected members after removing shared variants present in unaffected members. Only one non-synonymous mutation (p. Glu186Lys or E186K) in exon 6 of P2X7 gene segregated in HCM-affected individuals which was absent in unaffected family members and 100 clinically evaluated controls. The site of the mutation is highly conserved and led to complete loss of function which is in close vicinity to ATP-binding site-forming residues, affecting ATP binding, channel gating, or both. Mutations in candidate genes which were not segregated define clinical heterogeneity within affected members. P2X7 gene is highly expressed in the heart and shows direct interaction with major candidate genes for HCM. Our results reveal a significant putative HCM causative gene, P2X7, for the first time and show that germ-line mutations in P2X7 may cause a defective phenotype, suggesting purinergic receptor involvement in heart failure mediated through arrhythmias which need further investigations to be targeted for therapeutic interventions.
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Affiliation(s)
- Amitabh Biswas
- Department of Anthropology, University of Delhi, New Delhi, India
- College of Natural Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Ali Raza
- College of Natural Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Soumi Das
- Department of Anthropology, University of Delhi, New Delhi, India
| | - Mitali Kapoor
- Department of Anthropology, University of Delhi, New Delhi, India
| | - Rijith Jayarajan
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Ankit Verma
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | | | - Benrithung Murry
- Department of Anthropology, University of Delhi, New Delhi, India
| | - Sandeep Seth
- Department of Cardiology, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Balram Bhargava
- Department of Cardiology, All India Institute of Medical Sciences, New Delhi, 110029, India
| | - Vinod Scaria
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Sridhar Sivasubbu
- CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Vadlamudi Raghavendra Rao
- Department of Anthropology, University of Delhi, New Delhi, India.
- Department of Genetics, Osmania University, Hyderabad, India.
- Genome Foundation, Hyderabad, 500007, India.
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3
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Xu H, Dorn GW, Shetty A, Parihar A, Dave T, Robinson SW, Gottlieb SS, Donahue MP, Tomaselli GF, Kraus WE, Mitchell BD, Liggett SB. A Genome-Wide Association Study of Idiopathic Dilated Cardiomyopathy in African Americans. J Pers Med 2018; 8:E11. [PMID: 29495422 PMCID: PMC5872085 DOI: 10.3390/jpm8010011] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 02/17/2018] [Accepted: 02/21/2018] [Indexed: 01/03/2023] Open
Abstract
Idiopathic dilated cardiomyopathy (IDC) is the most common form of non-ischemic chronic heart failure. Despite the higher prevalence of IDC in African Americans, the genetics of IDC have been relatively understudied in this ethnic group. We performed a genome-wide association study to identify susceptibility genes for IDC in African Americans recruited from five sites in the U.S. (662 unrelated cases and 1167 controls). The heritability of IDC was calculated to be 33% (95% confidence interval: 19-47%; p = 6.4 × 10-7). We detected association of a variant in a novel intronic locus in the CACNB4 gene meeting genome-wide levels of significance (p = 4.1 × 10-8). The CACNB4 gene encodes a calcium channel subunit expressed in the heart that is important for cardiac muscle contraction. This variant has not previously been associated with IDC in any racial group. Pathway analysis, based on the 1000 genes most strongly associated with IDC, showed an enrichment for genes related to calcium signaling, growth factor signaling, neuronal/neuromuscular signaling, and various types of cellular level signaling, including gap junction and cAMP signaling. Our results suggest a novel locus for IDC in African Americans and provide additional insights into the genetic architecture and etiology.
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Affiliation(s)
- Huichun Xu
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Gerald W Dorn
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Amol Shetty
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Ankita Parihar
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Tushar Dave
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Shawn W Robinson
- Division of Cardiovascular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Stephen S Gottlieb
- Division of Cardiovascular Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Mark P Donahue
- Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, NC 27708, USA.
| | - Gordon F Tomaselli
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21218, USA.
| | - William E Kraus
- Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, NC 27708, USA.
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA.
| | - Braxton D Mitchell
- Division of Endocrinology, Diabetes and Nutrition, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
- Geriatrics Research and Education Clinical Center, Baltimore Veterans Administration Medical Center, Baltimore, MD 21201, USA.
| | - Stephen B Liggett
- Department of Internal Medicine and Molecular Pharmacology and Physiology, and the Center for Personalized Medicine and Genomics, University of South Florida Morsani College of Medicine, Tampa, FL 33612, USA.
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