Carnosinemia

Carnosinemia, also called carnosinase deficiency or aminoacyl-histidine dipeptidase deficiency, is a rare autosomal recessive metabolic disorder caused by a deficiency of carnosinase, a dipeptidase (a type of enzyme that splits dipeptides into their two amino acid constituents).

Carnosine is a dipeptide composed of beta-alanine and histidine, and is found in skeletal muscle and cells of the nervous system. This disorder results in an excess of carnosine in the urine, cerebrospinal fluid (CSF), blood and nervous tissue. Neurological disorders associated with a deficiency of carnosinase, and the resulting carnosinemia ("carnosine in the blood") are common.