Eight different variants in the PAH gene were identified among Qatari and non-Qatari cases with PKU, including p. Ala403Val, exon 3 deletion, p.Ala300Ser, c.169_171del, c.1199 G > C, c.293T > C, c.1184C > G, and c.1066-11G > A. Among PCD cases, 11 Qatari newborns were found to be homozygous for the pathogenic variant c.83G > T in the SLC22A5 gene. The gene discussed is SLC22A5; the disease is phenylketonuria.