For the 209 true PKU negatives, newborn sample S-119 was identified as a heterozygote carrier of the pathogenic PAH variant c.1064C > A and the remaining 208 newborns did not carry any PAH variants or other variants in the PTS, GCH1, PCBD1 and QDPR genes associated with BH4 deficiency. The gene discussed is QDPR; the disease is phenylketonuria.