Treatment responses vary between IEM‐NT, with some being curative, such as low dose l‐DOPA with dopa decarboxylase (DDC) inhibitor in autosomal dominant GCH1 deficiency, some with variable responses like in AADCD and TH deficiency (THD), and others being medically refractory, such as dopamine transporter deficiency syndrome (DTDS).15, 16, 17, 18. The gene discussed is DDC; the disease is tyrosine hydroxylase deficiency.