Analysis of the genetic and clinical data from a cohort of 25 patients, children and adults, with defects in the collagen VI (COL6A1-3) genes and followed up at the Marseille Neuromuscular Disease Reference Centre in France showed that :
- 5 had Ullrich-type muscular dystrophy, 15 had Bethlem myopathy and 5 had an intermediate form;
- 14 patients had an autosomal recessive form caused by 8 different pathogenic variants and 11 an autosomal dominant form caused by 8 other variants;
- the most common variant (c.1970-9G>A in the COL6A2 gene) affected 29% of patients;
- three of the pathogenic variants identified had not previously been described in the literature;
- in a sub-group of patients, the disease progressed more rapidly, with loss of walking in childhood, unrelated to a specific variant.
