X-linked dominant chondrodysplasia punctata: a case report and family studies.

Two major types of chondrodysplasia punctata have been delineated; a severe, recessively inherited, rhizomelic form and the less severe, dominantly inherited Conradi-Hünerman form. Clinico-genetic analysis of this latter form of CP uncovered a sub-group characterised by asymmetric involvement with linear or whorled skin patches of ichthyosiform erythroderma or atrophoderma, circumscribed cicatricial alopecia, asymmetrical cataracts and limb shortness. The mosaic pattern of the manifestations and the limitation of reported cases to females suggested an X-linked dominant gene which undergoes Lyonisation in the female and is lethal in the hemizygous male. We report on a family ascertained through a baby girl who had manifestations typical of the X-linked dominant form of CP and whose mother, 2 of 3 maternal aunts, and maternal grandmother all had less severe manifestations. The absence of male offspring for 3 generations and a history of 3 early miscarriages, along with the clinical variability in the affected females, provide further support for X-linked dominant inheritance of this disorder.