A PATIENT WITH A DEFICIENCY OF SERUM‐CARNOSINASE ACTIVITY

Abstract

Summary A patient with severe mental retardation, generalized convulsions and electro‐encephalo‐graphic abnormalities has been described. A marked carnosinuria was observed on a regular diet as well as on a diet which was essentially free of carnosine. No carnosine was found in plasma of this patient on any occasion. The serum‐carnosinase activity was extremely diminished compared to control subjects. Oral loading with L‐carnosine resulted in a much greater excretion of the administered L‐carnosine compared to a control subject. The consanguineous parents of the patient also excreted large amounts of the dipeptide and had decreased serum‐carnosinase activities. Infusion with freshly prepared donor plasma, containing active carnosinase, resulted in a temporary elevation of the enzymic activity in serum and a decrease of carnosine excretion in urine.