We report a 14-year-old boy who had both Bethlem myopathy and recurrent hematuria and who carried a known de novo COL6A1 missense mutation c.877G > A (p.G293R).
Based on genetic analysis, five patients (five families) comprising four with IM and one with typical UCMD had missense mutations in the triple-helical domain of COL6A1, and ten patients (four families) with BM showed exon-14-skipping mutations.
Analysis of the literature indicates that the donor splice site of COL6A1 intron 14, associated with the phenotype of Bethlem myopathy or intermediate form, is a hot spot for ColVI myopathies.
Bethlem myopathy (BM) [MIM 158810] is a slowly progressive muscle disease characterized by contractures and proximal weakness, which can be caused by mutations in one of the collagen VI genes (COL6A1, COL6A2 and COL6A3).
Characterization of a rare case of Ullrich congenital muscular dystrophy due to truncating mutations within the COL6A1 gene C-terminal domain: a case report.
Position of glycine substitutions in the triple helix of COL6A1, COL6A2, and COL6A3 is correlated with severity and mode of inheritance in collagen VI myopathies.
Position of glycine substitutions in the triple helix of COL6A1, COL6A2, and COL6A3 is correlated with severity and mode of inheritance in collagen VI myopathies.
Skin abnormalities, including predisposition to keratosis pilaris and abnormal scarring, were described in Ullrich congenital muscular dystrophy (UCMD) and Bethlem myopathy (BM) patients carrying mutations in COL6A1, COL6A2, and COL6A3 genes, whereas COL6A5, previously designated as COL29A1, was linked to atopic dermatitis.