Absence of testicular steroid sulphatase activity in a boy with recessive X-linked ichthyosis and testicular maldescent.

We present a 14-year-old boy with recessive X-linked ichthyosis in whom only one testis could be found. In this apparently normal testis, a lack of activity of the enzyme steroid sulphatase was demonstrated. Several male patients with recessive X-linked ichthyosis have been reported to have testicular diseases, and it is suggested that this may be related to the absence of testicular steroid sulphatase activity.