What is Williams Syndrome and How is it Diagnosed?

After being ignored for nearly three decades, Williams Syndrome has recently become one of the most vigorously researched disabilities after autism. Autism is a highly diverse 'spectrum disorder' with poorly designated diagnoses, no identified cause, and no clearly defined genetic basis. Williams, in contrast, arises from an isolated genetic cause and produces a predictable set of traits and behaviors. It is perfect for studying not only how genes dictate intelligence and sociability, but also how our capacities for thought combine with our desire for relationships to create complex social behavior.

Williams Syndrome

Williams Syndrome was discovered in 1961 by J. C. P. Williams of New Zealand. During his job at a hospital, he noticed a pattern in some of his patients: many had elfin facial features, were small in stature, were overly friendly, and mentally slow. As it turns out, these common characteristics were a result of a genetic mutation; for a number of Williams' patients, 25 of their genes in chromosome 7 had been deleted during meiosis (cell division during sexual reproduction). Williams modestly labelled this syndrome with his own name, and it has been thoroughly researched since its discovery, with a recent surge in interest.

About 1 in 7,500 people have Williams Syndrome, compared with about 1 in 150 for autism and 1 in 800 for Down syndrome. It can occur with no family history. An estimated 20,000 to 30,000 people have it in the United States, and it occurs equally in both males and females. If a person with Williams Syndrome has a child, that child has a 50% chance of inheriting the disorder.

The specific genetic mutation that causes Williams occurs when DNA is torn during meiosis. Normally, the two strands that make up DNA's double helix part cleanly, like a zipper. But in Williams, about 25 'teeth' in one of the strands are torn loose during this parting.  

Symptoms

The damaged DNA results in cognitive deficits, mainly in abstract thought. Many members of the Williams population have a very vague sense of space; adults fail at six-piece jigsaw puzzles, get easily lost, and draw like preschoolers. These mental deficits generally subtract about 35 points from whatever I.Q. a person might have inherited.

Additionally, people with Williams exhibit cardiovascular problems, high calcium levels, infantile feeding problems, dental abnormalities, sensitive hearing, developmental delay, and learning disabilities. 

Williams people tend to talk a lot, and with pretty much anyone. They appear to truly lack social fear; indeed, brain scans have shown that the amygdala (the area in the brain that processes fear) shows no reaction when a person with Williams views angry or worried faces. Seemingly, they perceive all faces as friendly.

People with Williams tend to be oblivious to the subtleties of social interaction. They miss secondary meanings, ideas, and intentions that most of us infer based on facial expressions, body language, and stock phrasings. A person with Williams syndrome will probably misunderstand your intentions if you look at your watch and say: “Gee, look at the time! Well it’s been lovely talking with you.” They may smile energetically, agree that “this is nice” and inquire if you’ve ever visited Disney World. Because of this, people with Williams may experience difficulty deepening relationships. They know no strangers; yet, they can claim few friends. 

Diagnosis

An initial clinical diagnosis can be confirmed by a blood test. This technique is known as fluorescence in situ hybridization (FISH), a diagnostic test of the DNA. It detects the elastin deletion on chromosome 7 in more than 98% of individuals with Williams syndrome. 

A new diagnostic test for Williams syndrome is called micro-array analysis. This test not only identifies the elastin deletion but can provide additional information on the precise size of the deleted area on chromosome 7. 

Treatment 

Although some people with Williams can hold simple jobs, they require assistance managing their lives. Few can balance a checkbook because of their limited mathematical capabilities. Many would benefit from the aid of developmental psychologists, speech pathologists, and therapists who are familiar with Williams syndrome. Williams syndrome teams, with professionals available in all of these areas, should be combined with whatever local resources are available.