SCREENING OF 6-PYRUVOYL-TETRAHYDROPTERIN SYNTHASE ACTIVITY DEFICIENCY AMONG HYPERP HENYLALANINEMIC PATIENTS

Abstract

A deficiency of the phenylalanine hydroxylase activity or its cofactor tetrahydrobiopterin may
lead to hyperphenylalamnemia and as a result, loss of IQ, poor school performance, and
behavior problems occurs. Deficiency in 6-pyruvoyl-tetrahydropterin synthase activity is the
major cause of tetrahydrobiopterin deficient phenylketonuria. In this study, blood specimens
from 165 healthy volunteers and 127 children with phenylketonuria were used to determine
the 6-pyruvoyl-tetrahydropterin synthase activity. It was found that the activity of 6-
pyruvoyl- tetrahydropterin synthase was decreased in comparison with control [23.46 +/-
2.94, (mean +/- SD, mmol/ ml/h, n=I27) vs. 127.63 +/- 4.52, n=165), p<0.05]. Results of
this study indicate that examination of 6-pyruvoyl-tetrahydropterin synthase activity is helpful
and may lead to the diagnosis cause of hyperphenylalaninemia.