title: Hypoglycinaemia and psychomotor delay in a child with xeroderma pigmentosum.
abstract: Glycine is a nonessential amino acid that serves as both an inhibitory and an excitatory neurotransmitter. Hyperglycinaemia occurs in non-ketotic hyperglycinaemia, a primary defect in the glycine cleavage pathway, and as a secondary feature of several inborn errors of organic acid metabolism. However, specifically low levels of glycine have never been reported. Here we report a child with complementation group C xeroderma pigmentosum (XP) characterized by a splice donor mutation in the XPC gene, multiple skin cancers and specific and persistent hypoglycinaemia. He has cognitive delay, lack of speech, autistic features, hyperactivity and hypotonia, all unexplained by the diagnosis of XP group C, a non-neurological form of the disease. Treatment with oral glycine has improved his hyperactivity. Specific hypoglycinaemia could indicate a metabolic disorder producing neurological dysfunction. Whether it is related to or coincidental with the XP is unclear.
authors.affiliation: Division of Genetics, Children's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: E J
authors.initials: EJ
authors.lastname: Quackenbush
authors.forename: K H
authors.initials: KH
authors.lastname: Kraemer
authors.forename: W A
authors.initials: WA
authors.lastname: Gahl
authors.forename: V
authors.initials: V
authors.lastname: Schirch
authors.forename: D A
authors.initials: DA
authors.lastname: Whiteman
authors.forename: K
authors.initials: K
authors.lastname: Levine
authors.forename: H L
authors.initials: HL
authors.lastname: Levy
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D002648:Child; D012696:Glycine Hydroxymethyltransferase / Q000378:metabolism; D006801:Humans; D007003:Hypoglycemia / Q000378:metabolism / Q000503:physiopathology* / Q000523:psychology*; D008099:Liver / Q000201:enzymology / Q000378:metabolism; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D014983:Xeroderma Pigmentosum / Q000378:metabolism / Q000503:physiopathology* / Q000523:psychology*
chemical_list: D000596:Amino Acids; D012696:Glycine Hydroxymethyltransferase