Kniest dysplasia

Kniest dysplasia is a rare form of dwarfism caused by a mutation in the COL2A1 gene on chromosome 12. The COL2A1 gene is responsible for producing type II collagen. The mutation of the COL2A1 gene leads to abnormal skeletal growth and problems with hearing and vision. What characterizes Kniest dysplasia from other type II osteochondrodysplasia is the level of severity and the dumb-bell shape of shortened long tubular bones.

This condition was first described by Dr. Wilhelm Kniest in 1952, publishing the case history of a 3 1⁄2 year-old girl. Dr. Kniest noticed that his patient had bone deformities and restricted joint mobility. The patient also had short stature and later developed blindness, resulting from retinal detachment and glaucoma. Upon analysis of the patient's DNA in 1992, sequencing revealed deletion of a 28 base pair sequence encompassing a splice site in exon 12 and a G to A transition in exon 50 of the COL2A1 gene.

This condition is very rare and occurs less than 1 in 1,000,000 people. Males and females have equal chances of having this condition. Currently, there is no cure for Kniest dysplasia. Alternative names for Kniest Dysplasia can include Kniest syndrome, swiss cheese cartilage syndrome, Kniest chondrodystrophy, or metatrophic dwarfism type II.