Lamellar ichthyosis: response to etretinate with transglutaminase 1 recovery.

We studied a case of typical lamellar ichthyosis before and after etretinate treatment for the expression of transglutaminase 1 (TGK) and the presence or absence of the marginal band. Before the treatment, TGK was undetectable, although two other components of the marginal band, loricrin and involucrin, were detected by immunostaining in a normal pattern. The marginal band of the corneocytes was either thin and irregular or completely absent by electron microscopic study. After therapy with etretinate, 50 mg/day, the patient' s skin improved, and biopsies were taken at 4 and 8 months. Transglutaminase 1 became detectable by immunostaining. The marginal band was still absent in most corneocytes.