title: The relationship of plasma glutamine to ammonium and of glycine to acid-base balance in propionic acidaemia.
abstract: Hyperammonaemia is a common and serious complication of propionic acidaemia. Treatment of hyperammonaemia with sodium phenylacetate or phenylbutyrate has not been well studied in this disorder. We reviewed the medical records of 5 patients with propionic acidaemia over a 16-year period. We collected information on events where plasma amino acids and ammonium, plasma acids and acid-base balance, or all 3 parameters were obtained simultaneously. All patients were on protein-restricted diet and carnitine throughout the period. In contrast to hyperammonaemia in patients with a urea cycle disorder, plasma glutamine levels were below the normal mean and there was no correlation between plasma ammonium and glutamine levels. The absence of positive correlation between plasma glutamine and ammonium suggests that the routine use of sodium phenylacetate or phenylbutyrate to treat hyperammonaemia in propionic acidaemia should be questioned until further studies are done. Throughout follow-up of our propionic acidaemia patients, we have observed that plasma glycine levels correlated positively with serum bicarbonate. The association of high plasma glycine with good acid-base balance might have a potential role in management and warrants further investigation.
authors.affiliation: Department of Medical Genetics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia. zhassnan@kfshrc.edu.sa
authors.forename: Z N
authors.initials: ZN
authors.lastname: Al-Hassnan
authors.forename: S A
authors.initials: SA
authors.lastname: Boyadjiev
authors.forename: V
authors.initials: V
authors.lastname: Praphanphoj
authors.forename: A
authors.initials: A
authors.lastname: Hamosh
authors.forename: N E
authors.initials: NE
authors.lastname: Braverman
authors.forename: G H
authors.initials: GH
authors.lastname: Thomas
authors.forename: M T
authors.initials: MT
authors.lastname: Geraghty
mesh_terms: D000136:Acid-Base Equilibrium / Q000502:physiology*; D000592:Amino Acid Metabolism, Inborn Errors / Q000097:blood* / Q000178:diet therapy; D001639:Bicarbonates / Q000097:blood; D015415:Biomarkers; D018753:Diet, Protein-Restricted; D018450:Disease Progression; D005500:Follow-Up Studies; D005973:Glutamine / Q000097:blood*; D005998:Glycine / Q000097:blood*; D006801:Humans; D011422:Propionates / Q000097:blood*; D056693:Propionic Acidemia; D000644:Quaternary Ammonium Compounds / Q000097:blood*
chemical_list: D001639:Bicarbonates; D015415:Biomarkers; D011422:Propionates; D000644:Quaternary Ammonium Compounds; D005973:Glutamine; C029658:propionic acid; D005998:Glycine