Lysinuric protein intolerance.

Lysinuric protein intolerance is an autosomal recessive disorder which first appears as failure to thrive, vomiting and diarrhea in the infant after weaning from mother's milk. Later it manifests as failure to grow, muscular weakness and osteopenia associated with aversion to animal protein. Some patients become mentally retarded and have periods of stupor. The disease is characterized by marked lysinuria, and hyperammonemia after protein intake. According to accumulating evidence, the basic defect is deficient transport of diamino acids in the intestine, liver and kidney tubuli. Effective treatment is provided by supplementing protein food with extra arginine.