Summary
Deficiency of dihydropteridine reductase causes a variant form of phenylketonuria associated with a devastating neurological disease characterized by mental retardation, hypokinesis and other features relating to basal ganglia disorder. Hyperphenylalaninaemias with tetrahydrobiopterin deficiency make up about 1–3% of all hyperphenylalaninaemias. We describe three patients from Calabria, a southern region of Italy, who have a dihydropteridine reductase deficiency, caused by the same mutation (p.L14P) also found in the nearby region of Sicily. We report the evolution of clinical and biochemical data during the treatment of these patients where we used prolactin serum determination to adapt the specific therapy. This report suggests that serum prolactin levels can be a good biomarker for optimal dosage of hydroxylated precursors in long-term treatment monitoring.
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Abbreviations
- BH4 :
-
tetrahydrobiopterin
- CSF:
-
cerebrospinal fluid
- DHPR:
-
dihydropteridine reductase
- DQ:
-
development quotient
- DQPR :
-
dihydropteridine reductase gene
- 5-HIAA:
-
5-hydroxindoleacetic acid
- HPA:
-
hyperphenylalaninaemia
- 5-HTP:
-
5-hydroxytryptophan
- HVA:
-
homovanillic acid
- Phe:
-
phenylalanine
- Trp:
-
tryptophan
- Tyr:
-
tyrosine
References
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Acknowledgments
We thank the John F. Kennedy Instituttet – Statens Øjenklinik (DK) for performing molecular analyses in our patients. We would like to thank in particular Dr Moller, PhD and Dr Nielsen, MD, for their kind cooperation.
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Communicating editor: Nenad Blau
JIMD Short Report #100 (2007) Online
Competing interests: None declared
References to electronic databases: DHPR deficiency: OMIM +261630. Dihydropteridine reductase: EC16.99.7.
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Concolino, D., Muzzi, G., Rapsomaniki, M. et al. Serum prolactin as a tool for the follow-up of treated DHPR-deficient patients. J Inherit Metab Dis 31 (Suppl 2), 193–197 (2008). https://doi.org/10.1007/s10545-007-0788-3
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DOI: https://doi.org/10.1007/s10545-007-0788-3