Muscular dystrophies with collagen-VI deficiency: predictive indices of the long-term phenotype?

Collagen VI myopathies (or collagenopathies VI) represent a group of muscular dystrophies whose clinical expression ranges from severe and early forms of infancy (congenital muscular dystrophy of Ullrich) to relatively benign forms ( Bethlem myopathy, LGMD R22 or D5), passing through many intermediate forms. The collagen VI deficiency, a key protein of the extracellular matrix, is objectified on fibroblast cultures and confirmed by the detection of sequence variants in one of the three genes encoding the constituent elements of collagen VI, the a1, a2 and a3 chains. Transmitted in an autosomal recessive or dominant mode, these neuromuscular diseases appear to share that they cause retractile myopathy, bringing orthopedic and mainly respiratory complications. 

In an article published in January 2021, the clinical and genetic data of 54 Spanish patients and 65 American patients, all with collagen VI myopathy, were compiled and analyzed by an international consortium of scientists looking for long-term phenotype severity predictive factors. Of all the parameters studied, two caught their attention: first the child’s ability to get up off the ground without help, and second to descend four steps without holding onto the handrail. These elements, appreciable from the age of 5, can be used individually or in future clinical trials. 


Association of Initial Maximal Motor Ability with Long-term Functional Outcome in Patients with COL6-related Dystrophies. D Natera-de Benito, A Reghan Foley, C Domínguez-González et al. Neurology. 2021 (Jan).