Congenial Muscle Diseae (CMD) refers to a broad, heterogenous group of disorders that are usually apparent at birth or within the first two years of life. Congenital Muscular Dystrophy, Congenital Myopathy, Congenital Myasthenic Syndrome, and Myofibrilar Myopathy all fall under the umbrella of Congenital Muscle Disease, each having numerous subtypes of their own.
All congenital muscle disorders are spectrum disorders, meaning that symptoms vary widely in both severity and age of onset. Milder phenotypes, or phenotypes where symptoms are not recognized early in life are often referred to as Limb-Girdle Muscular Dystrophies (LGMD), but are caused by mutations in the same genes as CMD phenotypes.
For the purposes of classifying the subtypes followed in this registry, we will include the LGMDs both under their associated CMD subtype, as well as under their own, separate listing.