SNP Shot: Genomic Insights

Otospondylomegaepiphyseal dysplasia (OSMED) is a genetic disorder affecting skeletal development, causing noticeable facial differences and profound hearing impairment. The name itself indicates the affected areas: "oto-" refers to the ears, "spondylo-" to the spinal bones, and "omegaepiphyseal" to the enlarged ends (epiphyses) of the long bones in the limbs. OSMED shares many characteristics with Weissenbacher-Zweymüller syndrome and Stickler syndrome type III. Because all three disorders result from mutations in the same gene, distinguishing between them can be challenging, leading some experts to suggest they are variations of a single underlying condition.

Individuals with OSMED are typically of short stature due to shortened leg bones. Other skeletal issues include enlarged joints, disproportionately short limbs (arms, hands, and fingers), and flattened vertebrae (platyspondyly). Consequently, affected individuals often suffer from back and joint pain, restricted joint mobility, and early-onset arthritis.

A hallmark of OSMED is severe hearing loss, primarily affecting high-frequency sounds. Distinctive facial features include prominent eyes, a flat nasal bridge, an upturned nose with a bulbous tip, and a receding lower jaw. Cleft palate is almost universally present at birth in infants with OSMED.

Inheritance:

OSMED follows an autosomal recessive inheritance pattern. This means that a person must inherit two copies of the mutated gene (one from each parent) to develop the condition. The parents, who each carry only one copy of the mutated gene, are typically asymptomatic carriers.