Association Between PAH Mutations and VNTR Alleles in the West Azerbaijani PKU Patients.

INTRODUCTION We report the frequency of IVS10nt546, R261Q, S67P, R252W, and R408W mutations linked to PAH VNTR alleles in the west Azerbaijani PKU patients. MATERIAL AND METHODS VNTR alleles and IVS10nt546, R261Q, S67P, R252W, R408W mutations were studied in a total of 20 PKU patients by PCR and RFLP-PCR. OUTCOMES Our analysis showed that 95% of cases were homozygote for an allele containing eight-repeat VNTR (VNTR8); while 5% were homozygote for an allele containing three-repeat VNTR (VNTR3). The IVS10nt546, R252W, and R261Q mutations were associated with VNTR8 allele, and also, R252W and S67P mutations were associated with VNTR3 allele. VNTR8 was common among mutant alleles as were IVS10nt546-VNTR8 (50%), R252W-VNTR8 (2.5%), and R261Q-VNTR8 (22.5%). The association of VNTR3 was found as R252W-VNTR3 (2.5%) and S67P-VNTR3 (2.5%) among studied cases. The frequency of IVS10nt546-VNTR8/IVS10nt546-VNTR8, IVS10nt546-VNTR8/ND-VNTR8, IVS10nt546-VNTR8/R252W-VNTR8, R261Q-VNTR8/R261Q-VNTR8, R261Q-VNTR8/ND-VNTR8, and S67P-VNTR3/ R252W-VNTR3 were 30%, 35%, 5%, 20%, 5%, and 5%, respectively. R408W mutation was not found in this study. CONCLUSIONS The present report is the first in its own kind in the west Azerbaijani population (Iran) and implies that the most common PKU mutation in this population, IVS10nt546, is exclusively associated with VNTR8 allele, and IVS10nt546-VNTR8 alleles testing should be considered for routine carrier screening and prenatal diagnostic setting.