Beneficial Effect of BH Treatment in a 15-Year-Old Boy with Biallelic Mutations in DNAJC12.

Background: Biallelic mutations in DNAJC12 were recently identified as a BH-responsive cause of hyperphenylalaninemia (HPA). Outcome was only favorable when treatment was initiated early in life. We report on a 15-year-old boy with HPA due to a homozygous deletion in DNAJC12 in whom - despite his advanced age - treatment was initiated.