An autosomal dominant disorder associated with a deletion on chromosome 7. Individuals with this syndrome have an “elfin” facial appearance, mild to moderate intellectual disability, delayed acquisition of motor milestones, and persistent gross and fine motor clumsiness. In contrast, they often possess extraordinary talents in music and verbal fluency.
Williams syndrome (WS) is characterized by distinctive facial features, cardiovascular disease, a specific cognitive profile, unique personality, cognitive impairments, and developmental delay. Elevated blood calcium levels and connective tissue abnormalities are also common. WS is a rare genetic disorder that occurs in 1 in 20,000 births. It is a dis¬ order that is present at birth and affects both males and females in all ethnic groups. The disorder was first described by J. C. P. Williams of New Zealand in 1961. The cause was unknown at that time; however, in 1993, the genetic etiology was discovered. The disorder is a result of the deletion of a portion of the long arm of Chromosome 7 at Band qll.23, which contains the elastin gene (ELN). The elastin gene is a protein that provides strength and elasticity to the vessel walls. WS can occur sporadically in families, and the deletion can be maternal or paternal. The extent of the deletion varies, leaving no two individuals with exactly the same problems. If the disorder is suspected, it can be confirmed by a blood test using the technique called fluorescent in situ hybridization (FISH; Williams Syndrome Association).
A rare congenital disorder caused by a deletion of part of chromosome 7 characterized by impaired growth, heart disease, hypercalcemia, mental retardation, sensitivity to loud sounds, and “elfin” facial features, among other anomalies. Some children with WS are described as excessively sociable, hyperactive, and musically talented, but these behavioral markers are not universally present.