Siblings With Leukoencephalopathy

Two consanguineous siblings presented with developmental regression and emerging spasticity. Cranial magnetic resonance imaging in both showed diffuse leukoencephalopathy. Further investigation established the siblings as having complex 1 deficiency consequent to a novel homozygous mutation in NDUFV1, a nuclear-encoded subunit of complex 1. Diffuse leukoencephalopathy may be a presentation of complex 1 deficiency.