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.
Journal article
2017-11-01T00:00:00+00:00
27
1043 - 1046
3
Alpha-dystroglycan, DPM3, Dolichol-P-mannose synthase, Limb girdle muscular dystrophy, Dystroglycans, Female, Homozygote, Humans, Mannosyltransferases, Membrane Proteins, Middle Aged, Muscle, Skeletal, Muscular Dystrophies, Limb-Girdle, Mutation, Phenotype