Mild non-BH4-deficient hyperphenylalaninemia (HPANBH4) is a rare metabolic disorder characterized by mild hyperphenylalaninemia (HPA) and a range of variable neurologic symptoms, including movement abnormalities and intellectual impairment.
HPANBH4 has an autosomal-recessive pattern of inheritance.
The disorder is caused by homozygous and compound heterozygous mutations in the DNAJC12 gene, which encodes a molecular chaperone belonging to the DnaJ/HSP40 family of proteins.
[citation needed] Mild non-BH4-deficient hyperphenylalaninemia was first reported in 6 patients from 4 unrelated consanguineous families by a large group of researchers in 2017.
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