Med Wieku Rozwoj 2002 Jul-Sep;6(3):193-202
Klinika Pediatrii, Instytut Matki i Dziecka, 01-211Warszawa, ul. Kasprzaka 17a, Poland.
Atypical phenylketonuria is the consequence of the deficiency of tetrahydrobiopterin (BH4) - cofactor of phenylalanine hydroxylation. The type of the disease depends on the metabolic defect of synthesis or regeneration of the cofactor. The secondary deficiency of neurotransmitters - dopamine and serotonin is the reason of very severe clinical course and brain damage. Ten cases of atypical phenylketonuria are presented: 8 of the defect of 6-pyrogronyl-tetrahydropterin synthase, 1 of dihydropteridine reductase, 1 of GTP cyclohydrolase. In 7 cases the diagnosis was confirmed by molecular studies. The age of the children at the time of diagnosis was from 3 weeks to 7 years. In 8 children pharmacological treatment was implemented without limitation of dietary intake of phenylalanine. Treatment period was from 9 months to 18.5 years. Treatment effectiveness is differentiated and independent of the age of diagnosis. Physical development in all but one patient is retarded and in all of them microcephaly is present. After treatment, mental development scores in 6 cases improved evidently (in 2 - up to normal values, in 4 - close to normal). No improvement was achieved in 2 cases (brothers). Detailed analysis of the clinical course in patients with similar age of diagnosis and start of treatment and with identical genotypes revealed significant differences in clinical course and treatment effectiveness. No explanation for this fact has been found.
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