Diastrophic dysplasia (disastrophic dwarfism) is a rare congenital disorder. The characteristics of the disorder are short stature, short limbs, abnormal development of bones, unusual shape of joints, progressive abnormal curvature of the spine, abnormal tissue changes of the outer and malformations of the head and facial (craniofacial) area.
The disorder was first delineated in 1960, and was called diastrophic dwarfism. The term ‘diastrophic’ is derived from a Greek root meaning distorted. In 1977, at the Second International Conference for Nomenclature for Constitutional Diseases of Bone, the name of the disorder was changed from diastrophic dwarfism to diastrophic dysplasia
Diastrophic dysplasia is caused by mutations in the SLC26A2 gene. It is the gene that provides instructions for making a protein that is essential for the normal development of cartilage and for its conversion to bone. The mutation in the SLC26A2 gene alters the structure of developing cartilage, preventing bones from forming properly and resulting in the skeletal problems.
Diastrophic dysplasia patients have short stature, with very short arms and legs. Usually, there is early-onset joint pain (osteoarthritis) and joint deformities called contractures that restrict movement. These complications can make it difficult for one to walk, and it worsens with age.
Diastrophic dysplasia is also linked to inward and downward-turning foot (a clubfoot), progressive abnormal curvature of the spine and unusually positioned thumbs. Swelling of the external ears is also common which might lead to deformed ears.
Another skeletal disorder called atelosteogenesis type 2 has similar signs and the disorder is often confused with that. Diastrophic dysplasia is less severe than atelosteogenesis type 2, though affected infants can also have breathing problems apart from skeletal problems.
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