AMPD deficiency is a rare genetic disorder caused by a deficiency of the enzyme adenosine monophosphate deaminase (AMPD). This enzyme is crucial for the breakdown of adenosine monophosphate (AMP) in muscle cells. When AMPD is deficient, it can lead to muscle cramps, fatigue, and exercise intolerance, especially during high-intensity activities. The condition is inherited in an autosomal recessive manner, meaning that a person must inherit two copies of the mutated gene to exhibit symptoms. Diagnosis is typically made through blood tests that measure enzyme activity. While there is no cure, management focuses on lifestyle adjustments and avoiding triggers that can lead to symptoms.