SNP Shot: Genomic Insights

Loeys-Dietz syndrome (LDS) is a condition impacting connective tissue, which provides support and flexibility to various body structures like bones, ligaments, muscles, and blood vessels.

There are five subtypes of LDS, designated types I through V, each linked to a specific genetic cause. The signs and symptoms of LDS can appear at any point from childhood to adulthood, varying in severity, regardless of the specific type.

A key characteristic of LDS is an enlarged aorta, the major blood vessel carrying blood from the heart. This enlargement can weaken the aorta, leading to aneurysms (bulges in the vessel wall) or aortic dissections (tears in the aorta's layers). Individuals with LDS may also experience aneurysms or dissections in other arteries, as well as arteries with unusual twists (arterial tortuosity).

Skeletal issues are common in LDS patients. These may include craniosynostosis (premature fusion of skull bones), scoliosis (spinal curvature), pectus excavatum (sunken chest) or pectus carinatum (protruding chest), clubfoot (inward-turning foot), flat feet, or elongated limbs with joint contractures (limited joint movement). Dural ectasia, an abnormal enlargement of the membrane surrounding the brain and spinal cord, can occur but usually doesn't cause problems. Instability or malformation of neck vertebrae is also common and can lead to spinal cord injuries. Some individuals develop osteoarthritis, frequently affecting the knees, hands, wrists, and spine.

People with LDS may bruise easily and develop unusual scars. Their skin is often described as translucent, with stretch marks (striae) and visible veins. Some individuals may experience spontaneous pneumothorax (collapsed lung) or hernias (organ protrusion through muscle gaps). Other features may include widely spaced eyes (hypertelorism), misaligned eyes (strabismus), bifid uvula (split uvula), and cleft palate (opening in the roof of the mouth).

Immune system problems are also frequently seen in individuals with LDS, such as food allergies, asthma, or inflammatory conditions like eczema or inflammatory bowel disease.

Inheritance:

LDS follows an autosomal dominant inheritance pattern. This means only one copy of the mutated gene is needed to cause the condition. About 75% of cases result from a new gene mutation with no family history. The remaining cases involve inheriting the mutation from an affected parent.