Emery-Dreifuss Muscular Dystrophy 7, Autosomal Dominant

A number sign (#) is used with this entry because of evidence that Emery-Dreifuss muscular dystrophy-7 (EDMD7) is caused by heterozygous mutation in the TMEM43 gene (612048) on chromosome 3p25.

Description

Emery-Dreifuss muscular dystrophy is a genetically heterogeneous muscular disease that presents with muscular dystrophy, joint contractures, and cardiomyopathy with conduction defects (summary by Liang et al., 2011).

For a discussion of genetic heterogeneity of EDMD, see 310300.

Clinical Features

Liang et al. (2011) reported 2 unrelated Japanese patients with adult-onset Emery-Dreifuss muscular dystrophy. The first patient was a 40-year-old man who was diagnosed with typical clinical EDMD with limb-girdle type muscular dystrophy with cardiac conduction defects and muscle biopsy that showed marked fiber size variation with scattered internal nuclei. He died soon after, and no other medical records were available. He reportedly had an affected son, suggesting autosomal dominant inheritance, but the son was lost to follow-up. The second patient was a 68-year-old woman who had slowly progressive muscle weakness at atrophy involving the proximal muscles. These features were noted at age 64 when she had a pacemaker implanted for atrial fibrillation with bradycardia. Muscle biopsy showed a necrotic and regenerating process. There was no family history of a similar disorder.

Inheritance

Emery-Dreifuss muscular dystrophy-7 is inherited as an autosomal dominant trait (Liang et al., 2011).

Molecular Genetics

Based on the putative role for TMEM43 in the nuclear envelope, Liang et al. (2011) analyzed the TMEM43 gene in 41 patients with Emery-Dreifuss muscular dystrophy who were negative for mutations in known EDMD-related genes and identified different heterozygous missense mutations in 2 unrelated individuals (612048.0002 and 612048.0003).