Genetic condition awaiting consideration - Conradi-Hunermann-Happle Syndrome
Conradi-Hunnermann-Happle Syndrome (CHHS) is an X-linked dominant disorder that has cutaneous, skeletal, and ocular manifestations; it is also referred to as X-linked dominant chondrodysplasia punctata. CHHS is caused by mutations in the emopamil binding protein (EBP) gene, which is located on the short arm of the X chromosome. Most patients with CHHS are girls with a heterozygous EBP mutation.
The EBP deficiency that underlies CHHS results in accumulation of 8-dehydrocholesterol and 8(9)-cholestenol in the plasma, skin, and other tissues. The EBP mutations that underlie CHHS are lethal in male fetuses because of their hemizygous state.Patients with CHHS are born with ichthyosiform erythroderma that is characterized by feathery, adherent scale and a distribution along Blaschko lines. The erythroderma usually resolves during the first year of life. Subsequently, residual streaks and swirls of follicular atrophoderma and hyper- or hypopigmentation remains evident. Scalp involvement results in patchy, scarring alopecia. Skeletal abnormalities include short stature, craniofacial anomalies (e.g., frontal bossing, malar hypoplasia, and a flat nasal bridge), asymmetric limb reduction defects, vertebral malformations, hip dysplasia, and chondrodysplasia punctata (stippled calcifications of the epiphyses). Ocular anomalies include cataracts, microphthalmia, microcornea, glaucoma, and atrophy of the retina and optic nerve.
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Page last updated: 09 November 2012