Williams syndrome is a rare genetic disorder that can lead to problems with development.

Williams syndrome is a rare condition caused by missing genes. Parents may not have any family history of the condition. However, a person with Williams syndrome has a 50% chance of passing the disorder on to each of his or her children. The cause usually occurs randomly.

Williams syndrome occurs in about 1 in 8,000 births.

One of the 25 missing genes is the gene that produces elastin, a protein that allows blood vessels and other tissues in the body to stretch. It is likely that having only one copy of this gene results in the narrowing of blood vessels seen in this condition.

• Delayed speech that may later turn into strong speaking ability and strong learning by hearing
• Developmental delay
• Easily distracted, attention deficit disorder (ADD)
• Feeding problems including colic, reflux, and vomiting
• Inward bend of the small finger (clinodactyly)
• Learning disorders
• Mild-to-moderate mental retardation
• Narrowing of the large artery that leaves the heart (aorta)
• Personality traits including being very friendly, trusting strangers, fearing loud sounds or physical contact, and being interested in music
• Short compared to the rest of the person's family
• Slack joints that may change to stiffness as patient gets older
• Sunken chest (pectus excavatum)
• Unusual appearance of the face
  • Flattened nasal bridge with small upturned nose
  • Long ridges in the skin that run from the nose to the upper lip (philtrum)
  • Prominent lips with an open mouth
  • Skin that covers the inner corner of the eye (epicanthal folds)
  • Partially missing teeth, defective tooth enamel, or small, widely-spaced teeth

Signs include:

• Blood vessel narrowing including supravalvular aortic stenosis, pulmonary stenosis, and pulmonary artery stenosis
• Farsightedness
• High blood calcium level (hypercalcemia) that may cause seizures and rigid muscles
• High blood pressure
• Unusual pattern ("stellate" or star-like) in iris of the eye

Tests for Williams syndrome:

• Blood pressure check
• Blood test for missing chromosome (FISH test)
• Echocardiography combined with Doppler ultrasound
• Kidney ultrasound