Collagen VI-related myopathy

Synonyms Spectrum of phenotypes: Mild: Bethlem myopathy/ benign congenital muscular dystrophy Intermediate: Limb-girdle muscular dystrophy; myosclerosis myopathy Severe: Ullrich myopathy/ congenital atonic sclerotic muscular dystrophy First described by Ullrich in 1930 and Bethlem in 1976 respectively [1]. Caused by mutations in any of the 3 genes which code for collagen type VI synthesis, COL6A1, COL6A2 and COL6A3 [2]. Collagen VI is a major contributor to stability of the extracellular matrix. The remaining function of Collagen VI determines the clinical severity of the disorder [3,4]. Considered different entities in the past, Bethlem and Ullrich myopathy are now considered extremes in the spectrum of Collagen VI myopathy. Both inheritance (mostly autosomal recessive) and de-Novo mutations (mostly autosomal dominant) are possible, the latter is more common. Combined prevalence is estimated at approximately 1 in 100,000 births (Varying data for subtypes). Diagnosis relies on muscle biopsy and molecular genetic testing. There exists no causative treatment.