Center for Human Genetics and Laboratory Diagnostics, Dr. Klein, Dr. Rost and Colleagues

Congenital Contractural Arachnodactyly (CCA) [Q87.4]

OMIM numbers: 121050, 612570 (FBN2)

Dr. rer. nat. Christoph Marschall

Scientific Background

Congenital contractural arachnodactyly (CCA) is a rare autosomal dominant disorder. Just like Marfan syndrome it is characterized by arachnodactyly, dolichostenomelia, chest deformities and kyphoscoliosis. However, in contrast to Marfan syndrome CCA does not present cardiovascular or ocular symptoms.

All causative mutations identified so far are located in the FBN2 gene which is homologous to FBN1. Fibrillin 2, the gene product of FBN2, is mostly expressed in elastic tissue like the aortic tunica media and along the bronchial tubes. All FBN2 mutations detected so far are located in the region of exons 23–34 — an analogous region that, if mutated in the FBN1 gene, is associated with the severe type (neonatal type) of Marfan syndrome. Similar to FBN1 most mutations in FBN2 lead to cysteine substitutions in EGF-like domains.