Conradi-Hünermann-Happle syndrome (X-linked dominant chondrodysplasia punctata) confirmed by plasma sterol and mutation analysis

Abstract

Conradi-Hünermann-Happle syndrome, or X-linked dominant chondrodysplasia punctata, is a rare genetic disorder characterized by skeletal dysplasia, stippled epiphyses, cataracts, transient ichthyosis and atrophic residua in a mosaic pattern. Mutations in the gene encoding the emopamil-binding protein have been identified as an underlying cause. A 5-year-old girl presented for evaluation of ill-defined patches of cicatricial alopecia. In addition, subtle follicular atrophoderma, esotropia, craniofacial asymmetry and short stature were noted. Her history revealed widespread scaly erythema and eye surgery for congenital cataract in the first months of life. Diagnosis of Conradi-Hünermann-Happle syndrome was confirmed by plasma sterol analysis showing markedly elevated levels of 8(9)-cholestenol and 8-dehydrocholesterol and by detection of a missense mutation (c.307G>A; p.E103K) in the emopamil-binding protein gene. We suggest that plasma sterol analysis is a reliable method of establishing the diagnosis of Conradi-Hünermann-Happle syndrome, even in patients with less striking phenotypical changes beyond infancy.