We present a case of an infant with homozygous damaging mutations in SCYL2 and a severe neurodevelopmental disorder characterized by microcephaly, arthrogryposis multiplex, optic atrophy, epilepsy, recurrent infections, autonomic dysfunction (recurrent sterile febrile illness, unexplained tachycardia, intermittent hypotension, unexplained vomiting, and constipation), and congenital brain anomalies including agenesis of the corpus callosum, ponto-cerebellar volume reduction, and non-specific white matter abnormalities. The gene discussed is SCYL2; the disease is Leber hereditary optic neuropathy.