Updated Listing of Mutation Map at the Human Phenylalanine Locus among Egyptian Population

Phenylketonuria is the most common inborn error of amino acid metabolism in Egypt with a relatively higher incidence of 1:7,500. Unrelated fifty-one PKU probands were selected from the database-records at the Medical Genetics Center, AinShams University-Cairo. We analyzed the DNA samples using polymerase chain reaction (PCR) combined with restriction enzyme assays, or allele specific oligonucleotide (ASO) testing and direct sequencing to detect 10 PAH gene mutations in exons 2, 3, 6, 7 and 11. We interestingly identified a novel missense CpG site R243P mutation. Moreover, three new known mutations L48S, delEX3 and Y277D unreeled in the Egyptian population. The ten detected mutations covered 58% representing 47 positive chromosomes. The most common mutation was represented by IVS10nt546 (10.8%), while the total missense mutations in our sample group account for the majority of mutations 40%. The high heterozygosity of the mutant PAH locus in Egypt suggests that multiple founder events would explain the presence of hyperphenylalaninemia in Egypt. Further studies will however be necessary to fully exploit the potential of PAH gene analysis to reconstruct the genetic history of PKU in Egypt in context with migrations among European and Mediterranean populations.