Wilson disease. Comparative ultrastructure in a sibship of nine.

Comparative electron microscopy was done on liver tissue from a family of nine siblings to determine whether presymptomatic, affected patients with Wilson disease could be differentiated from heterozygous, normal carriers. Two of the nine had developed the neurologic manifestations of the disease; three others were considered to be homozygous but normal, two were heterozygous and normal, and two were classified as genotypically uncertain because of borderline biochemical abnormalities. Alterations of the mitochondria and endoplasmic reticulum suggestive of copper toxicity were present in both the heterozygous and the genotypically uncertain siblings, and a clear distinction could not be made on this basis. The severity of the abnormalities appeared to correlate with liver copper level, and organelle changes were found to precede lipid accumulation.