This phenomenon is best illustrated by the leukodystrophies caused by DARS2 (leukoencephalopathy with brainstem and spinal cord involvement and high lactate, LBSL), EARS2 (leukoencephalopathy with thalamus and brainstem involvement and high lactate, LTBL), and AARS2 mutations (ovario-leukoencephalopathy). The gene discussed is DARS2; the disease is leukodystrophy.