Adenosine monophosphate deaminase deficiency type 1
Adenosine monophosphate deaminase deficiency type 1 or AMPD1, is a human metabolic disorder in which the body consistently lacks the enzyme AMP deaminase, in sufficient quantities. This may result in exercise intolerance, muscle pain and muscle cramping.
Source: Wikipedia — Adenosine monophosphate deaminase deficiency type 1 (CC BY-SA 4.0)