Is Williams Syndrome the same as Down Syndrome?


What is Williams Syndrome vs. Down Syndrome?

Both Williams syndrome and Down syndrome are chromosomal disorders affecting people from birth. However, Williams syndrome is caused by a missing chromosome, while Down syndrome is caused by an extra chromosome.

What is Williams Syndrome?

Williams syndrome is a genetic disease that affects approximately one in 25,000 births. The syndrome is named after Dr. JCP Williams, who was first diagnosed with the disease. He saw a trend in children at his hospital receiving treatment for cardiovascular problems. These children shared traits such as similar facial features and unusually friendly and outgoing demeanor.

Williams syndrome is also called:

What is Down syndrome?

Of all chromosomal diseases, Down’s syndrome is the most common with one in 700 babies diagnosed with Down syndrome. Most people are born with 46 chromosomes, but those with Down syndrome have an extra copy of chromosome 2.

Although the physical characteristics and behaviors are very similar, there are three different types of Down syndrome:

  • Trisomy 21: About 95% of people diagnosed with Down syndrome have trisomy 21. In this type, every cell in your body has three copies of chromosome 21 instead of the usual two.
  • Down syndrome with translocation: About 3% of people diagnosed with Down syndrome have an extra part or an entire chromosome 21, but it is attached to a different chromosome rather than being a completely separate 21 chromosome.
  • Mosaic Down Syndrome: About 2% of people with Down syndrome have cells with an extra 21 chromosome, but other cells have the two standard copies of the chromosome.

What are the signs of Williams syndrome compared to Down syndrome?

Signs of Williams syndrome

Typical markers for Williams syndrome include:

  • Facial Features: People diagnosed with Williams syndrome often have a broad forehead, a short, wide nose, full cheeks, and a wide mouth with full lips. These characteristics are sometimes considered elves.
  • Personality: People with Williams syndrome are outgoing and tend to be very interested in other people. They are very empathetic towards others, but are also very anxious, often accompanied by phobias. Attention deficit disorder (ADD) is also common in people with Williams syndrome.
  • Cardiovascular disease: The missing genetic code in chromosomes can make large blood vessels too narrow. This form of cardiovascular disease is called supravalvular aortic stenosis (SVAS), and it commonly occurs in people with Williams syndrome. If left untreated, it can cause shortness of breath, high blood pressure, chest pain, and heart failure.
  • Developmental Problems: Children with Williams disease often have problems with the development of motor skills and gross fine motor skills.

Signs of Down syndrome

People with Down syndrome may look and have similar qualities, but the conditions manifest differently for each person.

  • Intellectual development: In general, children with Down’s syndrome have a lower IQ and speak more slowly than other children.
  • Facial Features: People diagnosed with Down syndrome often have a flattened face, especially through the nose, and almond-shaped eyes that tilt upward. They also have smaller ears and a short neck.
  • Health Concerns: Half of all babies born with Down syndrome have heart defects that can be life threatening. Plus, Down syndrome increases your risk of developing Alzheimer’s disease earlier in life.

What Causes Williams Syndrome Versus Down Syndrome?

Causes of Williams syndrome

Williams syndrome occurs when the genetic code is missing from chromosome 7, which contains around 25 genes. Due to this genetic deficiency, people with Williams syndrome do not produce enough proteins like elastin. This is the reason for many of the cardiovascular and physical characteristics most associated with Williams syndrome.

Causes of Down syndrome

Similar to Williams syndrome, Down syndrome occurs because of a chromosomal disorder resulting from an extra copy of chromosome 21. Although Down syndrome does not tend to be familial, one in three children with Down’s syndrome have one. parent carrying a translocated chromosome 21. .

The mother’s age at conception is linked to an increased risk of your baby developing the disease. For pregnancies when the mother is 20 years old, the chance of having a baby with Down syndrome is one in 2,000. By age 40, the risk increases to one in 100.

How to Diagnose Williams Syndrome Versus Down Syndrome

Diagnose Williams syndrome

Your doctor will ask you about signs and symptoms that you or your child have that are similar to Williams syndrome. The diagnosis will also include:

  • Physical examination assessing characteristics associated with the disease
  • Echocardiogram and electrocardiogram (ECG) to check blood vessels
  • DNA blood test to check for missing genes

There are two tests used to provide a confirmed diagnosis of Williams syndrome. The first is a FISH test, which is used to look for missing chromosomes in people with Williams syndrome.

A chromosomal DNA chip uses millions of markers to determine which pieces of DNA are missing or where there are extra pieces of DNA. This gives a better idea of ​​the severity of a person’s physical and mental impact.

Diagnose Down syndrome

Since this is a common chromosomal disease, two tests are used to diagnose Down syndrome during pregnancy. This helps doctors prepare to identify and treat any heart defects present at birth.

A screening test tells you your chances of having a baby with Down syndrome based on your age, health, and genetics. Diagnostic tests are done first using the mother’s blood and then the amniotic fluid around the baby in the womb.

If your screening test during pregnancy shows a high likelihood of Down syndrome, your doctor may perform diagnostic tests to confirm. These may include:

Treatments for Williams syndrome versus Down syndrome

Treating Williams syndrome

While some symptoms of Williams syndrome can shorten the expected lifespan, infants and children who are diagnosed can live a long time with proper treatment.

Your treatment plan will be personalized based on the symptoms and the severity of your case. Interventions can include:

  • Feeding therapy for infants with feeding problems
  • Physiotherapy for weak muscles or developmental delays
  • Special education programs for children with developmental delays
  • Behavioral advice
  • Medication for attention deficit disorder or anxiety
  • Surgery to treat life-threatening heart defects
  • Drugs or diet changes for excess calcium in the blood

Treating Down Syndrome

There is no cure for Down syndrome. Early detection is the key to increasing the life expectancy of a child born with Down syndrome. Surgery may be needed to treat health problems like heart defects. Other treatments include services such as:

  • Physical therapy
  • Occupational therapy
  • Speech therapy
  • Special education

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Medical examination on 02/19/2021

The references

Centers for Disease Control and Prevention: “Down Syndrome Facts”.

Global Down Syndrome Foundation: “Congenital Heart Defects and Down Syndrome:” What Parents Should Know “.

Kennedy Krieger Institute: “Genetic, Metabolic and Chromosomal Disorders”.

National Down Syndrome Society: “What is Down Syndrome?” “

National Institute on Aging: “Alzheimer’s disease in people with Down’s syndrome”.

National Organization for Rare Diseases: “William Syndrome”.

Stanford Medicine: “William Syndrome”.

St. Louis Children’s Hospital: “William Syndrome”.


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