There are more than 50 characteristic features of Down syndrome. Each child's symptoms vary in number and severity. But many of these characteristics and features also occur in children who do not have Down syndrome.

General characteristics

Most children with Down syndrome have some of the following physical traits:

• Short stature. A child often grows slowly and, as an adult, is shorter than average.
• Weak muscles (hypotonia) throughout the body. A child may seem to have less strength than other children of the same age. Weak abdominal muscles also make the stomach stick out. Normally, children's stomach muscles gradually strengthen around age 2.
• A short, wide neck with excess fat and skin. Usually, this trait is less obvious as the child gets older.
• Short, stocky arms and legs. Some children also have a wide space between the big toe and second toe.
• A single crease across the center of the palms of the hands. This is called a transverse palmar crease or simian line.

Facial features

Down syndrome often results in distinct facial features, such as:

• Small, low-set ears.
• Irregularly shaped mouth and tongue. The child's tongue may partly stick out. The roof of the mouth (palate) may be narrow and high with a downward curve.
• A nasal bridge that looks pushed in. The nasal bridge is the flat area between the nose and eyes.
• Tissue buildup on the colored part of the eye (iris). These areas are known as Brushfield's spots and do not affect the child's vision.
• Irregular and crooked teeth that often come in late and not in the normal sequence.

Other medical conditions

A child may have other medical conditions related to Down syndrome, such as:

• Cognitive disability (mental retardation). Most children with Down syndrome have mild to moderate cognitive disability.
• Heart defects. About half of children with Down syndrome are born with a heart defect.¹ Most defects are diagnosed at birth or shortly thereafter.
• Diseases such as hypothyroidism, celiac disease, and eye conditions.

Children with Down syndrome are also prone to developing other health problems. For example, respiratory infections, hearing problems, and dental problems are common.