Moreover, variants in DNAJC12 cause a neurometabolic disorder, now defined as DNAJC12 deficiency, that manifests as hyperphenylalaninemia, accompanied by dopamine (DA) and serotonin depletion and parkinsonism16,18,20,21, revealing reduced levels of functional AAAHs. The gene discussed is DNAJC12; the disease is hyperinsulinemic hypoglycemia, familial, 4.