γ-glutamyl transpeptidase deficiency

γ-glu·ta·myl trans·pep·ti·dase de·fi·cien·cy (glooґtə-məl trans-pepґtĭ-dās) an autosomal recessive aminoacidopathy of glutathione synthesis, caused by mutation in the GGT1 gene (locus: 22q11.2), a member of the gamma-glutamyltransferase gene family. It is characterized by mental retardation, behavioral disorders, glutathionemia, and urinary excretion of glutathione, γ-glutamylcysteine, and cysteine. Called also glutathionuria.