Recessive X-linked ichthyosis (RXLI) is a genodermatosis belonging to the Mendelian Disorders of Cornification (MeDOC) and characterized by generalized hyperkeratosis and scaling of the skin.
RXLI affects almost exclusively males. It is the second most common type of ichthyosis with an estimated prevalence of 1 / 2,000 to 1 / 6,000 males.
X-linked ichthyosis is an epidermal lipid metabolism anomaly due to inactivating mutations or deletions in the steroid sulfatase gene, STS gene. Differential diagnosis includes ichthyosis vulgaris, autosomal recessive congenital ichthyosis (ARCI), namely lamellar ichthyosis, syndromic RLXI, or multiple sulfatase deficiency (see these terms). RXLI is transmitted as an X-linked recessive trait: it affects males and is inherited through female carriers. Female patients have rarely been reported.