Down syndrome symptoms vary from person to person and can range from mild to severe. However, children with Down syndrome have a widely recognized appearance.

The head may be smaller than normal and abnormally shaped. For example, the head may be round with a flat area on the back. The inner corner of the eyes may be rounded instead of pointed.

Common physical signs include:

• Decreased muscle tone at birth
• Excess skin at the nape of the neck
• Flattened nose
• Separated joints between the bones of the skull (sutures)
• Single crease in the palm of the hand
• Small ears
• Small mouth
• Upward slanting eyes
• Wide, short hands with short fingers
• White spots on the colored part of the eye (Brushfield spots)

Physical development is often slower than normal. Most children with Down syndrome never reach their average adult height.

Children may also have delayed mental and social development. Common problems may include:

• Impulsive behavior
• Poor judgment
• Short attention span
• Slow learning

As children with Down syndrome grow and become aware of their limitations, they may also feel frustration and anger.

Many different medical conditions are seen in babies born with Down syndrome, including:

• Birth defects involving the heart, such as an atrial septal defect or ventricular septal defect
• Dementia, Alzheimer's type may be seen
• Eye problems, such as cataracts (most children with Down syndrome need glasses)
• Early and massive vomiting, which may be a sign of a gastrointestinal blockage, such as esophageal atresia and duodenal atresia
• Hearing problems, probably caused by regular ear infections
• Hip problems and risk of dislocation
• Long-term (chronic) constipation problems
• Sleep apnea (because the mouth, throat, and airway are narrowed in children with Down syndrome)
• Teeth that appear later than normal and in a location that may cause problems with chewing
• Underactive thyroid (hypothyroidism)

A doctor can often make an initial diagnosis of Down syndrome at birth based on how the baby looks. The doctor may hear a heart murmur when listening to the baby's chest with a stethoscope.

A blood test can be done to check for the extra chromosome and confirm the diagnosis. See: Chromosome studies

Other tests that may be done include:

• Echocardiogram to check for heart defects (usually done soon after birth)
• ECG
• X-rays of the chest and gastrointestinal tract

Persons with Down syndrome need to be closely screened for certain medical conditions. They should have:

• Eye exam every year during infancy
• Hearing tests every 6 - 12 months, depending on age
• Dental exams every 6 months
• X-rays of the upper or cervical spine between ages 3 - 5 years
• Pap smears and pelvic exams beginning during puberty or by age 21