PAH and phenylketonuria: The current number of PAH variants in the PAHvdb ‐ Phenylalanine Hydroxylase Gene Locus‐Specific Database is 1041 (http://www.biopku.org/pah/search-results-browse.asp), of which circa 630 are disease‐causing mutations, associated with various degrees of PAH deficiency (BIOPKU; http://www.biopku.org/biopku/search-start.asp).