Two novel mutations in DNAJC12 identified by whole‐exome sequencing in a patient with mild hyperphenylalaninemia

BACKGROUND: Recently hyperphenylalaninemia (HPA) caused by variants in DNAJC12 was reported and this suggested a new strategy for diagnosis. But DNAJC12‐associated HPA is a rare in Chinese population so far. METHODS: The clinical information and blood samples from the patient and his family members were collected and analyzed. Whole‐exome sequencing (WES) was used to identify the causative gene. RESULTS: We reported a newborn patient with HPA, having excluded the causes in common genes associated with HPA. By using whole‐exome sequencing, novel compound heterozygosity mutations in DNAJC12 were found, namely c.306C>G (p.His102Gln) and c.182delA (p.Lys61Argfs*6). Administering a diet with low phenylalanine combined with tetrahydrobiopterin and neurotransmitter precursors were shown to be effective in preventing neurodevelopmental delay for these patients. CONCLUSION: Our finding confirms the diagnosis of DNAJC12‐associated HPA and suggests that genetic detection of DNAJC12 should be considered when newborn screening results are positive for HPA.