MEOX1

Klippel-Feil syndrome

At least three mutations in the MEOX1 gene have been found to cause Klippel-Feil syndrome. This condition is characterized by the abnormal joining (fusion) of two or more spinal bones in the neck (cervical vertebrae) and a variety of other features affecting many parts of the body. The MEOX1 gene mutations result in a lack of functional homeobox protein MOX-1. While the effect of the loss of this protein on vertebral development is unclear, it is likely that absence of this protein leads to unregulated somite segmentation and incorrect vertebral positioning. As a result, the cervical vertebrae do not separate during development but instead are fused together. It is unclear why this condition affects the cervical vertebrae more severely than other bones.