Congenital muscular dystrophies

The phenotypic categorization of patients with COL6-related dystrophies based on early clinical signs is challenging. We hypothesized that individuals who achieved more complex motor abilities by the age of five years would continue to demonstrate a milder clinical phenotype throughout life. In this study, we stratified the phenotypes of 121 patients with COL6-RD from Spain (n = 56) and the US (n = 65) into three categories according to the maximal motor ability achieved: (1) achieved rising from floor only with assistance = Ullrich congenital muscular dystrophy; (2) achieved rising from floor unassisted = intermediate COL6-RD, and (3) achieved stair climbing (ascending a minimum of four stairs without use of the railing) = Bethlem myopathy.