Emery-Dreifuss muscular dystrophy is a condition that primarily affects muscles used for movement (skeletal muscles) and the heart (cardiac muscle). Among the earliest features of this disorder are joint deformities called contractures. Contractures restrict the movement of certain joints, most often the elbows, ankles, and neck, and usually become noticeable in early childhood. Most affected individuals also experience muscle weakness and wasting that worsen slowly over time, beginning in muscles of the upper arms and lower legs and later also affecting muscles in the shoulders and hips.

Mutations in several genes, including EMD, FHL1, and LMNA, can cause Emery-Dreifuss muscular dystrophy. Mutations in the EMD gene or, less commonly, in the FHL1 gene cause the X-linked type of the condition. Mutations in the LMNA gene cause both the autosomal dominant and autosomal recessive types of the condition.

The overall prevalence of Emery-Dreifuss muscular dystrophy is unknown. The X-linked type of this disorder affects an estimated 1 in 100,000 people. The prevalence of the autosomal dominant type is unknown, although it appears to be more common than the X-linked type. The autosomal recessive type appears to be very rare; only a few cases have been reported worldwide.

Emery-Dreifuss muscular dystrophy can have several different patterns of inheritance. When the condition is caused by mutations in the EMD or FHL1 gene, it is inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes in each cell. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. Males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.

Published Date: June 01, 2017
Published By: National Institutes of Health