Sex-linked ichthyosis and placental sulphatase C deficiency.

Ichthyosis was diagnosed in six boys born from pregnancies in which placental steroid sulphatase deficiency was present. In four cases the diagnosis of sex-linked ichthyosis was certain, in the other two the ichthyosis was probably of the sex-linked type. No arylsulphatase C activity could be demonstrated histochemically either in the epidermis of these boys, or in the epidermis of adults with sex-linked ichthyosis, whilst it was present in normal controls. In cultured skin fibroblasts steroid-sulphatase activity was extremely low. We conclude that deficiency of steroid sulphatase C or arylsulphatase C or a third functionally linked enzyme is an important factor in the pathogenesis of sex-linked ichthyosis.