| X-linked ichthyosis
A form of ichthyosis, with onset at birth or in early infancy and affecting males; characterized by scaling predominantly on the scalp, neck, and trunk that progresses centripetally; the palms and soles are spared; histologic manifestations are hyperkeratosis, a granular layer in the epidermis, and normal epidermal cell turnover; X-linked recessive inheritance, caused by mutation in the steroid sulfatase gene (STS) on Xp. | |