[Screening results and genetic analysis of neonatal tetrahydrobiopterin deficiency in Hainan Province from 2007 to 2019].

A total of 1 295 516 dried blood spots were collected from newborns in Hainan Province from 2007 to 2019 who participated in the screening of neonatal diseases, and 43 cases of hyperphenylalaninemia were diagnosed. Among the 43 cases, 8 cases were confirmed to have tetrahydrobiopterin deficiency (4 males and 4 females). The incidence of tetrahydrobiopterin deficiency among newborns in Hainan Province was 6.