Complex III (coenzyme Q-cytochrome-c oxireductase) consists of 11 subunits. Mitochondrial disorders caused by complex III defects are divided into 3 forms
A. Multisystemic disorders
1. GRACILE syndrome (Growth retardation, aminoaciduria, cholestatsis, iron overload, lactic acidosis, early death)
2. Leigh syndrome
B. Myopathy
C. Infantile histiocytoid cardiomyopathy
On imaging patinets may demonstrate cerebral atrophy, increased T2 signal in the thalami, basal ganglia, and periventricular white matter.