Myopathy, McArdle type
Type of disease: Rare conditions
Glycogen storage disease type 5 is a genetic disorder that prevents the body from breaking down glycogen. Glycogen is an important source of energy that is stored in muscle tissue. Signs and symptoms may include burgundy-colored urine, fatigue, exercise intolerance, muscle cramps, muscle pain, muscle stiffness, and muscle weakness. Symptoms tend to begin in early adulthood (20s-30s). It is caused by mutations in the PYGM gene and is inherited in an autosomal recessive fashion. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.