What does the name mean?
‘Sphondylos’ is a Greek term meaning vertebra. ‘Epiphysis’ refers to the ends of long bones that are adjacent to the joints. Therefore, spondylo-epiphyseal dysplasias are disorders that involve both the spine and the ends of long bones. There are many types of spondyloepiphyseal dysplasias (SED), including SED congenital and SED tarda. We will limit our discussion here to SED-congenita (SEDc).
How common is spondyloepiphyseal dysplasia?
As of 1994, approximately 175 well-documented cases of SEDc had been reported.
Is spondyloepiphyseal dysplasia inherited?
SED-congenita typically has an autosomal dominant pattern of inheritance; however, distinct cases of autosomal recessive inheritance have also been reported (3). Most cases of this dysplasia are due to spontaneous mutations (3). Gonadal mosaicism helps to explain why affected children are often times born to unaffected parents.
What causes spondyloepiphyseal dysplasia?
SED-congenita is caused by a mutation of the gene coding for Collagen Type II (COL2A1) found on Chromosome 12 (1). Type II collagen is a structural protein present in the intervertebral discs, cartilage, and the eyeball.