Infantile subacute necrotizing encephalopathy.
Clinically heterogenous, lots of different genes. Can be X-linked, mitochondrial or recessive!!! Main genetic problem is mitochondrial complex defect, but same disease can be caused by pyruvate dehydrogenase defect (actually a complex of enzymes).
Baby’s initial development may appear normal, although there may be failure to thrive. Lactate can be raised in serum. Progressive, often rapid, neurological deterioration including hypotonia, dystonia, seizures.
Lesions (necrotic, gliosis, spongiosis) seen in basal ganglia, brainstem, cerebellum, spinal chord. CSF lactate and pyruvate may be raised, even if serum normal.