X-Linked dominant chondrodysplasia punctata

Abstract

X-linked dominant chondrodysplasia punctata is a syndrome consisting of skeletal, ocular, and cutaneous anomalies with asymmetric involvement of the body. The skin lesions, the hallmark of this condition, are distributed in a linear or blotchy pattern and include congenital ichthyosiform erythroderma, systematized atrophoderma mainly involving the hair follicles, and circumscribed alopecia. The remaining scalp hair is in part normal and in part irregularly twisted and coarse. The eyebrows and lashes are sparse. The nails may be flattened and split into layers. Thirty-five cases of this new syndrome are reviewed, and an additional observation is reported. The ratio of females to males is 36:0. The concept of X-linked dominant chondrodysplasia punctata has been suggested, and it has been postulated that there is a connection between the mosaic phenotype and the limitation to the female sex. Both facts would be explained by an X-linked gene giving rise to a pattern of lyonization in females, and lethal in hemizygous males. The classification of chondrodysplasia punctata thus includes three forms: the rhizomelic type, the Conradi-Hünermann type, and the X-linked dominant type. Two of these, the rhizomelic type and the X-linked dominant type, are well-defined entities. Whether the Conradi-Hünermann type, after separation of the X-linked form, is still heterogeneous, remains to be determined.