描述
Chondrodysplasia Punctata 2, X Linked Dominant (CDPX2; CPDXD; CPXD; Conradi-Hunermann Syndrome; Happle Syndrome; Conradi-Hunermann-Happle Syndrome is caused by a mutation in the gene encoding delta(8)-delta(7) sterol isomerase emopamil-binding protein (EBP). EBP contains the code for the enzyme 3-beta-hydroxysteroid-Delta(8),Delta(7)-isomerase, which normally catalyzes the conversion of Delta(8)-sterols to their corresponding Delta(7)-isomers. A defect in this enzyme causes accumulation of 8-dehydrocholesterol and 8(9)cholestenol in the plasma. Symptoms include alopecia, dysmorphism, hyperkeratosis, ichthyosis, kyphoscoliosis, limb abnormalities and deformities, and mental retardation.