Spondyloepiphyseal Dysplasia Congenita

What is spondyloepiphyseal dysplasia congenita?

Spondyloepiphyseal dysplasia congenita is an inherited disorder of bone growth that results in short stature (dwarfism), skeletal abnormalities, and problems with vision and hearing. The name of the condition indicates that it affects the bones of the spine (spondylo-) and the ends (epiphyses) of long bones in the arms and legs. "Congenita" indicates that the condition is present from birth.

People with this condition have short stature from birth, with a very short trunk and neck and shortened limbs. Their hands and feet, however, are usually average-sized. Adult height ranges from 3 feet to just over 4 feet. Abnormal curvature of the spine (kyphoscoliosis and lordosis) becomes more severe during childhood and can cause problems with breathing. Instability of the spinal bones (vertebrae) in the neck may increase the risk of spinal cord damage. Other skeletal features include flattened vertebrae (platyspondyly), an abnormality of the hip joint in which the upper leg bones turn inward (coxa vara), and a foot deformity called a clubfoot. Arthritis often develops early in life.

People with spondyloepiphyseal dysplasia congenita have mild changes in their facial features. The cheekbones close to the nose may appear flattened. Some infants are born with an opening in the roof of the mouth (a cleft palate). Severe nearsightedness (high myopia) is common, as are other eye problems that can impair vision. About one quarter of people with this condition have hearing loss.

How common is spondyloepiphyseal dysplasia congenita?

This condition is very rare; the exact incidence is unknown.

What genes are related to spondyloepiphyseal dysplasia congenita?

Mutations in the COL2A1 gene cause spondyloepiphyseal dysplasia congenita.

Spondyloepiphyseal dysplasia congenita is one of a spectrum of skeletal disorders caused by mutations in the COL2A1 gene. This gene provides instructions for making a protein that forms type II collagen. This type of collagen is found mostly in cartilage and in the clear gel that fills the eyeball (the vitreous). It is essential for the normal development of bones and other tissues that form the body's supportive framework (connective tissues). Mutations in the COL2A1 gene interfere with the assembly of type II collagen molecules, which prevents bones and other connective tissues from developing properly.

How do people inherit spondyloepiphyseal dysplasia congenita?

Spondyloepiphyseal dysplasia congenita is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.

What other names do people use for spondyloepiphyseal dysplasia congenita?

• SEDc
• SED congenita
• SED, congenital type
• Spondyloepiphyseal dysplasia, congenital type