[Prenatal diagnosis of a harlequin fetus using electron microscopy]

We have diagnosed a Harlequin fetus at 22 weeks' gestation. Harlequin syndrome is a fatal, congenital disorder of keratinization whose biochemical basis is unknown. The parents were second cousins and had had four children, two with the Harlequin syndrome who had died at birth and two normal children. During the fifth pregnancy the parents asked us to find out if the fetus was affected. Multiple skin biopsies were done by fetoscopy during the 22nd week of gestation. On binocular loupe examination the skin appeared thickened and fragile to the touch; light and electron microscopy revealed a remarkably thickened stratum corneum with involvement of both follicular and interfollicular epidermis, a feature characteristic of a Harlequin fetus at term. The pregnancy was terminated in the 24th week of gestation: the fetus had all the characteristic clinical features of Harlequin fetus.