Congenital Muscular Dystrophies

Abstract

Congenital muscular dystrophies (CMD) are an expanding group of hereditary muscle diseases that show symptom onset at, or shortly after, birth. There is considerable phenotypic variability among CMD with regard to pattern and progression of muscle weakness, joint hyperflexibility and contractures as well as potential eye and structural brain abnormalities. More than 30 genes have now been associated with various forms of CMD. Although the presence of dystrophic features on muscle biopsy in affected patients was initially an important diagnostic feature of CMD, improved ease and access to genetic testing often obviates the need for muscle biopsy except in situations where indeterminate variants arise. With advancements in our understanding of the genetics of CMD, so has its classification changed. Clinicians must differentiate CMD from other diseases that present in early infancy including congenital myopathies (CM), congenital myasthenic syndromes (CMS) and congenital myotonic dystrophy. Once delineated, surveillance testing and anticipatory management varies among forms of CMD.