Amino acids of plasma and urine in diseases of muscle.

Abstract

Abnormal serum enzyme activity in Duchenne dystrophy is attributed to a defect of the muscle membrane. If true, small molecules like amino acids should leak into plasma and cause generalized aminoaciduria. Concentrations of 33 amino acids were determined in plasma and urine by column chromatography in 20 boys with Duchenne dystrophy and 20 controls. Taurine excretion was frequently abnormal in boys with Duchenne dystrophy when related to creatinine excretion. There is no characteristic abnormality of urinary amino acid excretion in Duchenne dystrophy. If taurine excretion is abnormal, it is not clearly due to an overflow aminoaciduria. No abnormality was found in 18 patients with myotonic, limb-girdle, or facioscapulohumeral dystrophy. One of four patients with the latter disorder had cystinuria (24:176-186, 1971). Key Words.— Duchenne dystrophy; amino acids; taurine; amino aciduria; muscle diseases.