描述
Homocarnosinosis is caused by an inherited defect in serum carnosinase, which converts homocarnosine to GABA (gamma aminobutyric acid). A defect in serum carnosinase causes accumulation of the brain specific dipeptide homocarnosine (Hca), in the CSF and brain. Symptoms include hypotonia, mental retardation, retinitis pigmentosa and spastic diplegia/quadriplegia.