Williams syndrome is a developmental disorder that affects many parts of the body. People with Williams syndrome typically have difficulty with visual-spatial tasks such as drawing and assembling puzzles, but they tend to do well on tasks that involve spoken language, music, and learning by repetition. Affected individuals have outgoing, engaging personalities and tend to take an extreme interest in other people. Attention deficit disorder (ADD), problems with anxiety, and phobias are common among people with this disorder. Affected people may also have increased calcium levels in the blood in infancy, developmental delays, problems with coordination, and short stature. Medical problems involving the eyes and vision, the digestive tract, and the urinary system are also possible
Young children with Williams syndrome have distinctive facial features including a broad forehead, a short nose with a broad tip, full cheeks, and a wide mouth with full lips. Many affected people have dental problems such as small, widely spaced teeth and teeth that are crooked or missing. In older children and adults, the face appears longer and more gaunt.
A form of cardiovascular disease called supravalvular aortic stenosis (SVAS) occurs frequently in people with Williams syndrome. SVAS is a narrowing of the large blood vessel that carries blood from the heart to the rest of the body. If this condition is not treated, the aortic narrowing can lead to shortness of breath, chest pain, and heart failure.
Williams syndrome is caused by the deletion of genetic material from a specific region of chromosome 7. The ELN gene is among the genes that are typically deleted in people with Williams syndrome. Researchers have found that loss of the ELN gene is associated with the connective tissue abnormalities and cardiovascular disease specifically SVAS.
The ELN gene provides instructions for making a protein called tropoelastin. Multiple copies of the tropoelastin protein attach to one another and are processed to form a mature protein called elastin. Elastin is the major component of elastic fibers, which are slender bundles of proteins that provide strength and flexibility to connective tissue. Elastic fibers are found in the intricate lattice that forms in the spaces between cells, where they give structural support to organs and tissues such as the heart, skin, lungs, ligaments, and blood vessels.
Methodology: Fluorescent in Situ Hybridization (FISH) Analysis
Purpose: Confirmation of Clinical Diagnosis
ICD-10 Code Q93.89
Test Requisition: Cytogenetics Requisition
Turn-around-time: 10-14 days
1. Bhattacharjee Y (2005). “Friendly faces and unusual minds”. Science. 310(5749):802-4.
2. Carrasco X, Castillo S, Aravena T, Rothhammer P, Aboitiz F (2005). “Williams syndrome: pediatric, neurologic, and cognitive development”. Pediatr Neurol. 32(3):166-72.
3. Meyer-Lindenberg A, Mervis CB, Berman KF (2006). “Neural mechanisms in Williams syndrome: a unique window to genetic influences on cognition and behavior”. Nat Rev Neurosci. 7(5):380-93. Review.
4. Brooke BS, Bayes-Genis A, Li DY (2003). “New insights into elastin and vascular disease”. Trends Cardiovasc Med. l;13(5):176-81. Review.
5. Milewicz DM, Urbán Z, Boyd C (2000). “Genetic disorders of the elastic fiber system”. Matrix Biol. 19(6):471-80. Review.