Spondyloepiphyseal dysplasia congenita

Spondyloepiphyseal dysplasia congenita, also known as Spranger-Wiedemann disease, is a form of dwarfism caused by mutations in the COL2A1 gene, which directs production of type II collagen found in cartilage and in the eye's vitreous gel. Faulty collagen assembly disrupts normal bone growth, producing a short trunk and neck, a barrel-shaped chest, flattened vertebrae, hip joint deformities and, in some cases, clubfoot, hearing loss or vision problems, while the hands and feet remain normal sized. The disorder is inherited in an autosomal dominant pattern, so a single altered gene copy is sufficient to cause it, and it occurs in roughly one in 100,000 births; many affected pregnancies end in stillbirth or early infant death. No cure exists, and care is limited to managing individual symptoms.