The authors report the successful prenatal diagnosis of ichthyosis in the fetus of a woman whose previous liveborn child was affected with 'harlequin ichthyosis'. The fetal diagnosis was established through analysis of ultrasonographically guided fetoscopic skin biopsies. These biopsies showed premature hyperkeratosis, most marked around hair follicles and sweat ducts, and forming plugs of hyperkeratotic debris. These observations were in distinct contrast to those in control fetuses, whose epidermis consists of squamous epithelium only a few cells in depth with minimal keratinization.
