A homozygous DPM3 mutation in a patient with alpha-dystroglycan-related limb girdle muscular dystrophy.
Neuromuscul Disord 2017;
27:1043-1046. [PMID:
28803818 DOI:
10.1016/j.nmd.2017.07.006]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/27/2017] [Accepted: 07/12/2017] [Indexed: 10/19/2022]
Abstract
Defects of O-linked glycosylation of alpha-dystroglycan cause a wide spectrum of muscular dystrophies ranging from severe congenital muscular dystrophy associated with abnormal brain and eye development to mild limb girdle muscular dystrophy. We report a female patient who developed isolated pelvic girdle muscle weakness and wasting, which became symptomatic at age 42. Exome sequencing uncovered a homozygous c.131T > G (p.Leu44Pro) substitution in DPM3, encoding dolichol-P-mannose (DPM) synthase subunit 3, leading to a 50% reduction of enzymatic activity. Decreased availability of DPM as an essential donor substrate for protein O-mannosyltransferase (POMT) 1 and 2 explains defective skeletal muscle alpha-dystroglycan O-glycosylation. Our findings show that DPM3 mutations may lead to an isolated and mild limb girdle muscular dystrophy phenotype without cardiomyopathy.
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