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Qin X, Li P, Qu HQ, Liu Y, Xia Y, Chen S, Yang Y, Huang S, Wen P, Zhou X, Li X, Wang Y, Tian L, Hakonarson H, Wu Y, Zhuang J. FLNC and MYLK2 Gene Mutations in a Chinese Family with Different Phenotypes of Cardiomyopathy. Int Heart J 2021; 62:127-134. [PMID: 33455984 DOI: 10.1536/ihj.20-351] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mutations in the sarcomeric protein filamin C (FLNC) gene have been linked to hypertrophic cardiomyopathy (HCM), as they have been determined to increase the risk of ventricular arrhythmia and sudden death. Thus, in this study, we identified a novel missense mutation of FLNC in a Chinese family with HCM, and, interestingly, a second novel truncating mutation of MYLK2 was discobered in one family member with different phenotype.We performed whole-exome sequencing in a Chinese family with HCM of unknown cause. To determine and confirm the function of a novel mutation of FLNC, we introduced the mutant and wild-type gene into AC16 cells (human cardiomyocytes): we then used western blotting to analyze the expression of FLNC in subcellular fractions, and confocal microscope to observe the subcellular distribution of the protein.As per our findings, we were able to identify a novel missense single nucleotide variant (FLNC c.G5935A [p.A1979T]) in the family, which segregates with the disease. FLNC expression levels were observed to be equivalent in both wild-type and p.A1979T cardiomyocytes. However, the expression of the mutant protein has resulted in cytoplasmic protein aggregations, in contrast to wild-type FLNC, which was distributed in the cytoplasm and did not form aggregates. Unexpectedly, a second truncating mutation, NM_033118:exon8:c.G1138T:p.E380X of the MYLK2 gene, was identified in the mother of the proband with dilated cardiomyopathy, which was not found in other subjects.We then identified the FLNC A1979T mutation as a novel pathogenic variant associated with HCM in a Chinese family as well as a second causal mutation in a family member with a distinct phenotype. The possibility that there is more than one causal mutation in cardiomyopathy warrants clinical attention, especially for patients with atypical clinical features.
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Affiliation(s)
- Xianyu Qin
- Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Ping Li
- Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Hui-Qi Qu
- Center for Applied Genomics, The Children's Hospital of Philadelphia
| | - Yichuan Liu
- Center for Applied Genomics, The Children's Hospital of Philadelphia
| | - Yu Xia
- Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Shaoxian Chen
- Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Yongchao Yang
- Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Shufang Huang
- Center for Applied Genomics, The Children's Hospital of Philadelphia
| | - Pengju Wen
- Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Xianwu Zhou
- Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Xiaofeng Li
- Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Yonghua Wang
- Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Lifeng Tian
- Center for Applied Genomics, The Children's Hospital of Philadelphia
| | - Hakon Hakonarson
- Center for Applied Genomics, The Children's Hospital of Philadelphia.,Department of Pediatrics and Division of Human Genetics, University of Pennsylvania
| | - Yueheng Wu
- Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
| | - Jian Zhuang
- Guangdong Cardiovascular Institute, Guangdong Provincial Key Laboratory of South China Structural Heart Disease, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences
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