Spondyloepiphyseal dysplasia and spondyloepimetaphyseal dysplasia

Spondyloepiphyseal dysplasia (SED) and spondyloepimetaphyseal dysplasia (SEMD) are a heterogeneous group of inherited skeletal disorders (osteochondrodysplasias) characterized by abnormal development of the spine (spondylo-), the ends of long bones (epiphyseal), and in the case of SEMD, also the growing portions of long bones (metaphyseal). These conditions primarily affect the skeletal system, leading to disproportionate short stature with a short trunk, abnormalities of the vertebral bodies (platyspondyly), and variable involvement of the limbs. The group encompasses multiple distinct subtypes, including spondyloepiphyseal dysplasia congenita (SEDc, caused by COL2A1 mutations), spondyloepiphyseal dysplasia tarda (SEDT, often X-linked due to TRAPPC2 mutations), and numerous forms of SEMD with varying genetic causes. Clinical features vary by subtype but commonly include short stature, barrel chest, kyphoscoliosis, lumbar lordosis, coxa vara, genu valgum, and joint pain or stiffness. Many patients develop early-onset osteoarthritis. Ocular complications such as myopia and retinal detachment can occur in COL2A1-related forms. Odontoid hypoplasia with cervical instability is a potentially serious complication in some subtypes, particularly SEDc, and may lead to spinal cord compression. Some forms are associated with hearing loss or cleft palate. There is currently no cure for SED or SEMD. Treatment is supportive and multidisciplinary, involving orthopedic management of skeletal deformities (including surgical correction of scoliosis, hip replacement, or cervical spine stabilization when needed), ophthalmologic monitoring, pain management, and physical therapy. Regular surveillance for cervical spine instability is critical in certain subtypes. Genetic counseling is recommended for affected families, as the inheritance pattern and prognosis vary significantly depending on the specific subtype and underlying genetic cause.

Common questions about Spondyloepiphyseal dysplasia and spondyloepimetaphyseal dysplasia