[MIM*268200] repeated paroxysmal attacks of muscle pain and weakness followed by passage of dark red-brown urine, often precipitated by intercurrent illness and diagnosed by demonstration of myoglobin in the urine; it is attributed to abnormal phosphorylase activity in skeletal muscle, but there may be more than one biologic type; probably autosomal recessive inheritance. In some cases, at least, there is deficiency of carnitine palmitoyl transferase. SYN: familial paroxysmal rhabdomyolysis.