Spondyloepiphyseal dysplasia congenita


Spondyloepiphyseal dysplasia congenita is a rare disorder of bone growth that results in dwarfism, characteristic skeletal abnormalities, and, in some instances, problems with vision and hearing. The name of the condition indicates that it affects the bones of the spine and the ends of bones, and that it is present from birth. The signs and symptoms of spondyloepiphyseal dysplasia congenita are similar to, but milder than, the related skeletal disorders achondrogenesis type 2 and hypochondrogenesis. Spondyloepiphyseal dysplasia congenita is a subtype of collagenopathy, types II and XI.

Presentation

People with spondyloepiphyseal dysplasia are short-statured from birth, with a very short trunk and neck and shortened limbs. Their hands and feet, however, are usually average-sized. This type of dwarfism is characterized by a normal spinal column length relative to the femur bone. Adult height ranges from 0.9 meters to just over 1.4 meters. Curvature of the spine progresses during childhood and can cause problems with breathing. Changes in the spinal bones in the neck may also increase the risk of spinal cord damage. Other skeletal signs include flattened vertebrae, a hip joint deformity in which the upper leg bones turn inward, and an inward- and downward-turning foot. Decreased joint mobility and arthritis often develop early in life. Medical texts often state a mild and variable change to facial features, including cheekbones close to the nose appearing flattened, although this appears to be unfounded. Some infants are born with a cleft palate. Severe nearsightedness is sometimes present, as are other eye problems that can affect vision such as detached retinas. About one-quarter of people with this condition have mild to moderate hearing loss.

Causes

Spondyloepiphyseal dysplasia congenita is one of a spectrum of skeletal disorders caused by mutations in the COL2A1 gene. The protein made by this gene forms type II collagen, a molecule found mostly in cartilage and in the clear gel that fills the eyeball. Type II collagen is essential for the normal development of bones and other connective tissues. Mutations in the COL2A1 gene interfere with the assembly of type II collagen molecules, which prevents bones from developing properly and causes the signs and symptoms of this condition.
Spondyloepiphyseal dysplasia congenita is inherited in an autosomal dominant pattern, which means one copy of the altered gene is sufficient to cause the disorder.

Management

There is no treatment for the underlying condition. Supportive/symptomatic treatment is based on the traits present in each person with the condition.

Notable people