| Modification Notes |
Sp8, also known as BTD, is a 508 amino acid nuclear protein that contains three C2H2-type zinc fingers. Existing as multiple alternatively spliced isoforms, Sp8 plays a crucial role in limb outgrowth and neuropore closure and is thought to mediate apical ectodermal ridge (AER) formation. The gene encoding Sp8 maps to human chromosome 7, which houses over 1,000 genes and comprises nearly 5% of the human genome. Defects in some of the genes localized to chromosome 7 have been linked to Osteogenesis imperfecta, Pendred syndrome, Lissencephaly, Citrullinemia and Shwachman-Diamond syndrome. The deletion of a portion of the q arm of chromosome 7 is associated with Williams-Beuren syndrome, a condition characterized by mild mental retardation, an unusual comfort and friendliness with strangers and an elfin appearance. Deletions of portions of the q arm of chromosome 7 are also seen in a number of myeloid disorders, including cases of acute myelogenous leukemia and myelodysplasia. |