Congenital myopathy with fiber type disproportion

Congenital fiber-type disproportion (CFTD) myopathy is a genetically heterogeneous disorder in which there is relative hypotrophy of type 1 muscle fibers compared to type 2 fibers on skeletal muscle biopsy. However, these findings are not specific and can be found in many different myopathic and neuropathic conditions. Clarke and North (2003) stated that the diagnosis of 'congenital fiber-type disproportion' as a disease entity is one of exclusion. They also suggested that the nonspecific histologic findings should be termed 'fiber size disproportion,' thus reserving the term CFTD for those cases in which no secondary cause can be found.

OMIM