A new congenital myopathy in a Norwegian family

A 6-y-old boy presented with a mild, and apparently non-progressive, congenital myopathy, primarily affecting explosive movements such as running and jumping. Five other cases, spanning four generations, were identified in his family. A dominant inheritance pattern was suggested. Quadriceps muscle histology showed a selective type II fibre atrophy, which is otherwise considered a non-specific change associated with a number of conditions.

A Norwegian boy with an inherited muscle weakness is presented. Based on clinical and laboratory investigations, and in light of the inheritance pattern, a previously undescribed congenital myopathy is suggested.