What are the genetic changes related to fibrochondrogenesis ?
Fibrochondrogenesis can result from mutations in the COL11A1 or COL11A2 gene. These genes provide instructions for making components of type XI collagen, which is a complex molecule that gives structure and strength to the connective tissues that support the body's joints and organs. Specifically, type XI collagen is found in cartilage, a tough but flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone, except for the cartilage that continues to cover and protect the ends of bones and is present in the nose and external ears. Type XI collagen is also part of the inner ear; the vitreous, which is the clear gel that fills the eyeball; and the nucleus pulposus, which is the center portion of the discs between vertebrae.  Mutations in the COL11A1 or COL11A2 gene impair the assembly of type XI collagen, in most cases leading to the production of abnormal collagen molecules. The defective collagen weakens connective tissues, impairing the formation of bones throughout the skeleton and causing changes in the eye and inner ear that lead to vision and hearing problems.