A novel DNAJB6 mutation causes dominantly inherited distal-onset myopathy and compromises DNAJB6 function

Abstract

Background: Mutations in the DNAJB6 gene have been identified as a rare cause of dominantly inherited limb-girdle muscular dystrophy or distal-onset myopathy.

Materials and methods: Exome sequencing was performed to investigate a Taiwanese family with a dominantly inherited distal-onset myopathy. Functional effects of the causal mutation were investigated in vitro.

Results: Exome sequencing of the two affected individuals in this family identified a heterozygous mutation, c.287C>T (p.Pro96Leu) in the DNAJB6 gene, which co-segregated with the myopathy within all 12 family members. Notably, this mutation is novel and localizes within the glycine and phenylalanine-rich (G/F) domain and alters an amino acid residue previously reported with a different mutation. Furthermore, immunofluorescence analyses and filter trap assay demonstrated that the c.287C>T (p.Pro96Leu) mutation possessed a dominant negative effect on the anti-aggregation function of DNAJB6 protein.

Conclusion: This study expands the molecular spectrum of DNAJB6 mutations and also emphasizes the pathogenic role of DNAJB6 dysfunction in distal-onset myopathy.

Keywords: DNAJB6; LGMD; distal-onset myopathy; exome sequencing; limb-girdle muscular dystrophy; myopathy.