SNP Shot: Genomic Insights

Williams syndrome is a developmental disorder impacting multiple bodily systems. It is characterized by varying degrees of intellectual disability or learning difficulties, specific personality traits, distinct facial characteristics, and cardiovascular issues affecting the heart and blood vessels.

Individuals with Williams syndrome often struggle with visual-spatial skills, such as drawing and puzzle-solving. However, they generally excel in areas like spoken language, music, and rote learning (memorization through repetition). They are typically outgoing and friendly, displaying a strong interest in interacting with others. Attention deficit disorder (ADD), anxiety issues, and phobias are commonly observed in individuals with this condition.

Young children with Williams syndrome often exhibit characteristic facial features including a wide forehead, puffiness around the eyes, a flattened nasal bridge, full cheeks, and a small chin. Many individuals experience dental problems such as small, widely spaced, crooked, or missing teeth. As they age, older children and adults tend to develop a longer face with a wide mouth and full lips.

Supravalvular aortic stenosis (SVAS), a type of cardiovascular disease, is prevalent in people with Williams syndrome. SVAS involves a narrowing of the aorta, the major blood vessel carrying blood from the heart to the body. Untreated SVAS can lead to shortness of breath, chest pain, and heart failure. Narrowing of other vessels can also occur, including the pulmonary artery (from the heart to the lungs) and the coronary arteries (supplying blood to the heart). Additionally, high blood pressure (hypertension) and stiff blood vessels have been documented in people with Williams syndrome. Individuals with Williams syndrome face increased risks when undergoing anesthesia.

Additional signs and symptoms of Williams syndrome include connective tissue abnormalities (affecting joints and organs), potentially leading to joint problems and soft, loose skin. Elevated calcium levels in the blood (hypercalcemia) may occur in infancy, along with developmental delays, coordination difficulties, and short stature. Vision and hearing problems, including sensitivity to sound (hyperacusis), are frequently associated with Williams syndrome. Digestive tract and urinary system issues are also possible. Obesity or diabetes may develop in adulthood.

Inheritance:

In most instances, Williams syndrome is not inherited. The chromosomal change typically arises spontaneously during the creation of reproductive cells (eggs or sperm) in a parent of an affected individual. These cases occur in people with no prior family history of the condition. However, an unaffected parent carrying a chromosomal inversion in the region of chromosome 7 linked to Williams syndrome increases the risk of having a child with the syndrome. Williams syndrome is considered an autosomal dominant condition, meaning that one copy of the altered chromosome 7 in each cell is sufficient to cause the disorder. In a small number of cases, individuals with Williams syndrome inherit the chromosomal deletion from a parent who also has the condition.