Secondary brain creatine deficiency may lead to diagnosis of ornithine aminotransferase (OAT) deficiency
(2015) Society for the Study of Inborn Errors of Metabolism — Location: Lyon, France (1.September.2015)
Files
No attached file found for this publication.
Details
- Authors
- et. al.
- Abstract
- (en) Background. OAT deficiency is a rare autosomal recessive disorder associated with gyrate atrophy of choroid and retina that leads to the diagnosis. Patients develop hyperornithinaemia, which inhibits arginine-glycine amidinotransferase, a rate-limiting enzyme in creatine production. Thus, high ornithine concentrations cause secondary creatine deficiency. We report the case of an OAT deficient patient diagnosed through secondary brain creatine deficiency. Case report : A 3-year-old boy presented with partial complex non febrile seizures, delayed psychomotor development, and a gradually slowing of head growth. Brain MRI spectroscopy showed increased NAA/creatine and choline/creatine ratios which suggested a brain creatine deficiency. Very-low urinary excretion of creatine and guanidinoacetate and low blood creatine suggested AGAT deficiency. Blood amino acids disclosed high ornitihine levels (1107μmol/l, normal:26– 56μmol/l) thus pointing towards OAT deficiency. Urinary excretion of ornithine, was highly increased. Ophthalmological exam showed normal visual acuity but funduscopy revealed areas of retinal thinning confirmed by optical coherence tomography. Electroretinogram revealed abnormal electrogene- sis. Genetic testing revealed a known homozygous nonsense mutation in the OAT gene. A 4-week trial of pyridoxine showed no change in ornithine plasma level. Significant reduction of plasma ornithine was achieved by dietary restriction of arginine. Conclusion. Secondary creatine deficiency may be a diagnostic clue for OAT deficiency.
- Affiliations
Citations
Paviolo, M., Germanaud, D., Paquay, S., Pichard, S., Imbard, A., Bui Quoc, E., Benoist, J.-F., Schiff, M., & et al. (2015). Secondary brain creatine deficiency may lead to diagnosis of ornithine aminotransferase (OAT) deficiency. Journal of Inherited Metabolic Disease, 38 (Suppl 1), 136. https://hdl.handle.net/2078.5/66187 (Original work published 2015)