Clinical Information

Muscular dystrophies are a heterogeneous group of neuromuscular conditions characterized by skeletal muscle wasting due to muscle dysfunction. The muscular dystrophies can be subdivided into the dystrophinopathies: Emery-Dreifuss muscular dystrophy, limb-girdle muscular dystrophies, distal myopathies, and congenital muscular dystrophies. A clinical diagnosis is typically based on distribution and severity of muscular involvement, mode of inheritance, and other associated symptoms.

The dystrophinopathies include Duchenne muscular dystrophy and Becker muscular dystrophy. These 2 forms are inherited in an X-linked manner and typically present with variable degrees of a limb-girdle pattern of weakness and can develop dilated cardiomyopathy. Emery-Dreifuss muscular dystrophy is characterized by the triad of joint contractures, slowly progressive muscle weakness and wasting, and cardiac involvement. Limb-girdle muscular dystrophy is characterized by weakness and wasting predominately of the hips, shoulders, and proximal extremity muscles. Distal myopathies are disorders with weakness and atrophy predominantly in the distal muscles. Congenital muscular dystrophies are progressive early-onset muscle disorders that often have brain and other organ involvement. They are characterized by hypotonia, delayed motor development, and progressive weakness.

Given the clinical overlap of muscular dystrophies, multigene panels can be an efficient and cost-effective way to establish a molecular diagnosis for individuals who are symptomatic.