Steroid sulphatase deficiency in patients initially diagnosed as ichthyosis vulgaris or recessive X-linked ichthyosis.

Twenty-one patients with ichthyosis were classified as either ichthyosis vulgaris (IV) (five cases) or recessive X-linked ichthyosis (RXLI) (sixteen cases) by using a steroid sulphatase assay of plantar callus and peripheral leukocytes. The patients had presented with various clinical manifestations, which had resulted in some initial misdiagnoses. Cases which initially resemble IV may in fact be RXLI, although we found that if a case is initially diagnosed as RXLI it is unlikely to be a case of IV.