Chorea presenting in infancy is often due to acute basal ganglia damage in the context of metabolic encephalopathies (aminoacidopathies, organic acidurias, Lesh-Nyhan syndrome), while in childhood auto-immune causes with normal brain imaging prevail (Sydenham's chorea, autoimmune encephalitides) and rare non-metabolic genetic conditions must also be considered (NKX2-1, PDE10A, GNAO1 mutations) [13]. The gene discussed is PDE10A; the disease is Organic aciduria.