Investigating the pathology of Emery–Dreifuss muscular dystrophy

EDMD (Emery–Dreifuss muscular dystrophy) is caused by mutations in either the gene encoding for lamin A/C (LMNA) located at 1q21.2–q21.3 or emerin (EMD) located at Xq28. Autosomal dominant EDMD caused by LMNA mutations is more common than the X-linked form and often more severe, with an earlier onset. At the histological and histochemical levels, both X-linked and autosomal dominant EDMD appear similar. However, individuals with the same genetic disorder often show remarkable differences in clinical severity, a finding generally attributed to the genetic background. The clinical and pathological findings in EDMD patients found to have mutations in more than one gene are also discussed. There is now much interest in the phenotype of several animal models for EDMD which should lead to an increased insight into the pathogenesis of this disorder, particularly that relating to the heart phenotype.