Early diagnosis of recessive X-linked ichthyosis: elevation of cholesterol sulfate levels in placental sulfatase deficiency before the onset of skin symptoms.

Children and adults with recessive X-linked ichthyosis have elevated levels of cholesterol sulfate, a substrate of the deficient enzyme microsomal sulfatase, in blood, erythrocyte membrane, and ichthyotic scale. We investigated cholesterol sulfate levels in patients with microsomal sulfatase deficiency before birth in amniotic fluid and in maternal plasma and erythrocytes, in cord blood (plasma and erythrocytes), and in plasma in the first month of life before and after onset of skin symptoms. Levels in amniotic fluid and cord blood were elevated. The plasma levels in the first month, before as well as after onset of skin symptoms, were within the range found in older patients with manifest skin symptoms.