RESUMO
The polymorphic variable number of tandem repeat [VNTR] genetic marker present at the 3' end of the phenylalanine hydroxylase [PAH] gene is commonly used for carrier detection among family members of phenylketonuria [PKU] patients. The utilization of this marker is solely dependent on the heterozygosity of its alleles [repeats] in the population. In the present study, we use this marker to investigate the carrier status of several PKU families in Isfahan. The VNTR marker was amplified using PCR with specific primers flanking the region. Evaluation of the length of the VNTR marker indicated the presence of 3, 7, 8, 9, 12 and 13 repeats with different frequencies. Alleles with 3 repeats had the highest [57.3%] and those with 13 repeats had the lowest [3%] frequency. Analysis of PKU patients and their families indicated that, the PAHVNTR marker was heterozygous among 78% of families. This study suggests that the PAHVNR marker could be a suitable marker in analyzing of carrier status among family members of PKU patients in Isfahan