Mutation spectrum of the PAH gene in the PKU patients from Khorasan Razavi province of Iran.

BACKGROUND

Characterization of the molecular basis of phenylketonuria (PKU) in North-east of Iran has been accomplished through the analysis of 62 unrelated chromosomes from 31 Iranian PKU patients.

METHODS

Phenylalanine hydroxylase (PAH) gene mutations have been analyzed by direct DNA sequencing exons 6, 7, 10 and 11.

RESULTS

A mutation detection rate of 74% was achieved. Eleven different mutations were found, with the most frequent mutation, IVS10-11G>A, accounting for 19% of Khorasan-Razavi PKU alleles. Ten mutations (R176X, E280K, IVS11+1G>C, S231P, Q383X, R243X, I224T, E390G, R252W and P281L) represent the rest PKU chromosomes. One novel mutation, Q383X in the homozygote form was identified which is located in the catalytic domain (residues143-410).

CONCLUSION

With this high detection rate of mutations in North-east of Iran, new strategy for carrier testing could be DNA sequencing of these four exons. The other exons and boundaries will be studied only when either one or no mutations are detected in the initial screen.