The organelle pathology and demonstration of mitochondrial superoxide dismutase deficiency in two patients with Dubin--Johnson--Sprinz syndrome.

1. Liver biopsies from two patients with the Dubin-Johnson-Sprinz syndrome were subjected to analytical subcellular fractionation by sucrose-density-gradient centrifugation and enzymic microassays. 2. A selective deficiency of mitochondrial superoxide dismutase has been demonstrated in these patients. 3. The significance of this enzyme deficiency is discussed in relation to the organelle pathology of the syndrome.