The clinical features of the type II and XI collagenopathies vary among the disorders, but there is considerable overlap.
Common signs and symptoms include problems with bone development that can result in short stature, enlarged joints, spinal curvature, and arthritis at a young age.
Some individuals with these disorders have distinctive facial features such as protruding eyes and a flat nasal bridge.
Type XI collagen, on the other hand, is composed of three different alpha chains: the products of the COL2A1, COL11A1, and COL11A2 genes.
Defective or reduced numbers of collagen molecules affect the development of bones and other connective tissues, causing the signs and symptoms of the type II and XI collagenopathies.