What are common complex III mitochondrial disorders?

Most are rare. Mitochondrial complex iii deficiency means defect in the third "complex" (structural unit) of the mitochondrial respiratory chain (chain of protein units that produces energy for our cells). All forms of complex iii deficiencies are rare. United mitochondrial foundation has excellent information on various types of mitochondrial diseases, including complex iii: http://bit.Ly/1meless.