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Lee HCH, Wong S, Sheng B, Pan NYK, Leung YKF, Lau KKD, Cheng YS, Ho LC, Li R, Lee CN, Tsoi TH, Cheung YFN, Fu YPM, Kan NCA, Chu YP, Au WCL, Yeung HMJ, Li SH, Cheung CFM, Tong HF, Hung LYE, Chan TYC, Li CT, Tong TYT, Tong TWC, Leung HYC, Lee KH, Yeung SYS, Lee SYB, Lau TCG, Lam CW, Mak CM, Chan AYW. Clinical and pathological characterization of FLNC-related myofibrillar myopathy caused by founder variant c.8129G>A in Hong Kong Chinese. Clin Genet 2020; 97:747-757. [PMID: 32022900 DOI: 10.1111/cge.13715] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/17/2020] [Accepted: 01/28/2020] [Indexed: 12/18/2022]
Abstract
FLNC-related myofibrillar myopathy could manifest as autosomal dominant late-onset slowly progressive proximal muscle weakness; involvements of cardiac and/or respiratory functions are common. We describe 34 patients in nine families of FLNC-related myofibrillar myopathy in Hong Kong ethnic Chinese diagnosed over the last 12 years, in whom the same pathogenic variant c.8129G>A (p.Trp2710*) was detected. Twenty-six patients were symptomatic when diagnosed; four patients died of pneumonia and/or respiratory failure. Abnormal amorphous material or granulofilamentous masses were detected in half of the cases, with mitochondrial abnormalities noted in two-thirds. We also show by haplotype analysis the founder effect associated with this Hong Kong variant, which might have occurred 42 to 71 generations ago or around Tang and Song dynasties, and underlain a higher incidence of myofibrillar myopathy among Hong Kong Chinese. The late-onset nature and slowly progressive course of the highly penetrant condition could have significant impact on the family members, and an early diagnosis could benefit the whole family. Considering another neighboring founder variant in FLNC in German patients, we advocate development of specific therapies such as chaperone-based or antisense oligonucleotide strategies for this particular type of myopathy.
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Affiliation(s)
| | - Shun Wong
- Department of Pathology, Princess Margaret Hospital, Hong Kong.,Pathology Department, St. Paul's Hospital, Hong Kong
| | - Bun Sheng
- Department of Medicine and Geriatrics, Princess Margaret Hospital, Hong Kong
| | - Nin-Yuan Keith Pan
- Department of Diagnostic Radiology, Princess Margaret Hospital, Hong Kong
| | | | | | - Yue Sandy Cheng
- Department of Clinical Pathology, Pamela Youde Nethersole Eastern Hospital, Hong Kong.,Department of Clinical Laboratory, Gleneagles Hong Kong Hospital, Hong Kong
| | - Luen-Cheung Ho
- Department of Pathology, Queen Elizabeth Hospital, Hong Kong
| | - Richard Li
- Department of Medicine, Pamela Youde Nethersole Eastern Hospital, Hong Kong
| | - Chi-Nam Lee
- Department of Medicine, Pamela Youde Nethersole Eastern Hospital, Hong Kong
| | - Tak-Hong Tsoi
- Department of Medicine, Pamela Youde Nethersole Eastern Hospital, Hong Kong
| | | | | | | | - Yim-Pui Chu
- Department of Medicine and Geriatrics, Princess Margaret Hospital, Hong Kong
| | - Wing-Chi Lisa Au
- Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong
| | | | - Siu-Hung Li
- Department of Medicine, North District Hospital, Hong Kong
| | | | - Hok-Fung Tong
- Department of Pathology, Princess Margaret Hospital, Hong Kong
| | | | | | - Chi Terence Li
- Department of Pathology, Princess Margaret Hospital, Hong Kong
| | | | | | | | - Ka-Ho Lee
- Department of Pathology, Princess Margaret Hospital, Hong Kong
| | | | | | | | - Ching-Wan Lam
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Chloe Miu Mak
- Department of Pathology, Princess Margaret Hospital, Hong Kong
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