Symptoms:

• 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
• 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
• 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 and tests:

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
• Slack joints that may change to stiffness as patient gets older
• 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