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Guanosine triphosphate cyclohydrolase I deficiency: early diagnosis by routine urine pteridine screening.
Pediatrics. 1987 Mar; 79(3):374-8.Ped

Abstract

A deficiency of hepatic guanosine triphosphate cyclohydrolase I is reported in a 4-month-old infant in whom positive results on a Guthrie phenylketonuria test in the neonatal period were found. Because of the significantly elevated serum phenylalanine levels a diagnosis of classical phenylketonuria was made, and dietary therapy was started. Urinary pteridine screening for cofactor variants, however, revealed extremely low levels of both neopterin and biopterin. This suggested the possibility of guanosine triphosphate cyclohydrolase I deficiency and led to additional confirmatory assays. Repeat urine, serum, and CSF pteridine profiles, combined with tetrahydrobiopterin-loading studies and the assay of guanosine triphosphate cyclohydrolase I activity in a liver biopsy, confirmed the defect. It is significant to note that the diagnosis was made before the onset of major clinical symptoms. This case illustrates the need for routine cofactor variant screening of all infants in whom hyperphenylalaninemia is diagnosed in the neonatal period.

Authors

No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Case Reports
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

3822637

Citation

Naylor, E W., et al. "Guanosine Triphosphate Cyclohydrolase I Deficiency: Early Diagnosis By Routine Urine Pteridine Screening." Pediatrics, vol. 79, no. 3, 1987, pp. 374-8.
Naylor EW, Ennis D, Davidson AG, et al. Guanosine triphosphate cyclohydrolase I deficiency: early diagnosis by routine urine pteridine screening. Pediatrics. 1987;79(3):374-8.
Naylor, E. W., Ennis, D., Davidson, A. G., Wong, L. T., Applegarth, D. A., & Niederwieser, A. (1987). Guanosine triphosphate cyclohydrolase I deficiency: early diagnosis by routine urine pteridine screening. Pediatrics, 79(3), 374-8.
Naylor EW, et al. Guanosine Triphosphate Cyclohydrolase I Deficiency: Early Diagnosis By Routine Urine Pteridine Screening. Pediatrics. 1987;79(3):374-8. PubMed PMID: 3822637.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Guanosine triphosphate cyclohydrolase I deficiency: early diagnosis by routine urine pteridine screening. AU - Naylor,E W, AU - Ennis,D, AU - Davidson,A G, AU - Wong,L T, AU - Applegarth,D A, AU - Niederwieser,A, PY - 1987/3/1/pubmed PY - 1987/3/1/medline PY - 1987/3/1/entrez SP - 374 EP - 8 JF - Pediatrics JO - Pediatrics VL - 79 IS - 3 N2 - A deficiency of hepatic guanosine triphosphate cyclohydrolase I is reported in a 4-month-old infant in whom positive results on a Guthrie phenylketonuria test in the neonatal period were found. Because of the significantly elevated serum phenylalanine levels a diagnosis of classical phenylketonuria was made, and dietary therapy was started. Urinary pteridine screening for cofactor variants, however, revealed extremely low levels of both neopterin and biopterin. This suggested the possibility of guanosine triphosphate cyclohydrolase I deficiency and led to additional confirmatory assays. Repeat urine, serum, and CSF pteridine profiles, combined with tetrahydrobiopterin-loading studies and the assay of guanosine triphosphate cyclohydrolase I activity in a liver biopsy, confirmed the defect. It is significant to note that the diagnosis was made before the onset of major clinical symptoms. This case illustrates the need for routine cofactor variant screening of all infants in whom hyperphenylalaninemia is diagnosed in the neonatal period. SN - 0031-4005 UR - https://wwww.unboundmedicine.com/medline/citation/3822637/Guanosine_triphosphate_cyclohydrolase_I_deficiency:_early_diagnosis_by_routine_urine_pteridine_screening_ L2 - http://pediatrics.aappublications.org/cgi/pmidlookup?view=long&pmid=3822637 DB - PRIME DP - Unbound Medicine ER -