GCH1 and phenylketonuria: Despite the general genetic similarities of our populations in the spectrum of variants, differences were observed with other Asian and European people; As a result, similar but more extensive studies are needed to investigate the distribution of disease‐causing variants in genes involved in non‐PKU hyperphenylalaninemia such as QDPR, PTS, PCBD1, GCH1, SPR, and DNAJC12 in the Iranian population.