BACKGROUND: Autosomal recessive mutations in the nuclear Twinkle (C10orf2) gene cause a mitochondrial DNA depletion syndrome (MDS) characterized by early onset hepatoencephalopathy.

METHODS: We report a severe, early onset encephalopathy and multisystem failure case caused by novel recessive Twinkle gene mutations. Patient clinical, laboratory, and pathological features are reported and Twinkle-associated MDS literature reviewed.

RESULTS: Typical presentation includes symptom onset before age six months, failure to thrive, psychomotor regression, epileptic encephalopathy, sensory axonal neuropathy, cholestatic liver dysfunction, and occasionally, renal tubulopathy, movement disorders, and ophthalmoplegia. Death is typical before age four years.

CONCLUSIONS: In the differential diagnosis of early onset encephalopathy and multisystem failure, MDS should be considered.