The nuclear muscular dystrophies.

Nuclear muscular dystrophies are referred to as inherited muscular dystrophies caused by mutations in genes--(STA) or lamina (LMNA)--encoding components of the nuclear envelope. Phenotypically, they present as Emery-Dreifuss muscular dystrophy (EDMD), limb-girdle muscle dystrophy 1B (LGMD1B), or dilated cardiomyopathy with conduction defects (DCM-CD). Genetically related are the Dunnigan-type of familial partial lipodystrophy (FPLD) and Charcot-Marie-Tooth neuropathy type 2 (CMT2B). Until now, approximately 70 unique STA mutations, leading to X-linked EDMD or DCM-CD, have resulted mostly in a complete lack of emerin. Further 50 mostly missense mutations in LMNA result in autosomal-dominant EDMD, autosomal-recessive EDMD, LGMD1B, DCM-CD, FPLD, or CMT2B. Independent of type or location of the mutations, emerinopathies and laminopathies show wide clinical intrafamilial and interfamilial variability. Although structural abnormalities of nuclei in animal and cell models have been observed, the molecular pathology of the nuclear muscular dystrophies needs still to be elucidated.