Down syndrome, or Down’s syndrome (primarily in the United Kingdom), trisomy 21, or trisomy G, is a genetic disorder caused by the presence of all or part of an extra 21st chromosome. Often Down syndrome is associated with some impairment of cognitive ability and physical growth, and a particular set of facial characteristics. Down syndrome in a fetus can be identified with amniocentesis during pregnancy, or in a baby at birth. Individuals with Down syndrome tend to have a lower than average cognitive ability, often ranging from mild to moderate developmental disabilities. A small number have severe to profound mental disability. The incidence of Down syndrome is estimated at 1 per 800 to 1,000 births, although it is statistically much more common with older mothers. Other factors may also play a role.early childhood intervention, screening for common problems, medical treatment where indicated, a conducive family environment, and vocational training can improve the overall development of children with Down syndrome. Although some of the physical genetic limitations of Down syndrome cannot be overcome, education and proper care will improve quality of life.
What are the symptoms of Down syndrome?
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 people with Down syndrome, including:
- Birth defects involving the heart, such as an atrial septal defect or ventricular septal defect
- Dementia 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)
Who is at highest risk?
Experts recommend genetic counseling for persons with a family history of Down syndrome who wish to have a baby. A woman’s risk of having a child with Down syndrome increases as she gets older. The risk is significantly higher among women age 35 and older. Couples who already have a baby with Down syndrome have an increased risk of having another baby with the condition. Tests such as nuchal translucency ultrasound, amniocentesis, or chorionic villus sampling can be done on a fetus during the first few months of pregnancy to check for Down syndrome. The American College of Obstetricians and Gynecologists recommends offering Down syndrome screening tests to all pregnant women, regardless of age.
When to seek urgent medical care?
A health care provider should be consulted to determine if the child needs special education and training. It is important for the child to have regular check ups with his or her doctor.
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.
Other tests that may be done include:
- Echocardiogram to check for heart defects (usually done soon after birth)
- 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
- Thyroid testing every 12 months
There is no specific treatment for Down syndrome. A child born with a gastrointestinal blockage may need major surgery immediately after birth. Certain heart defects may also require surgery. When breast-feeding, the baby should be well supported and fully awake. The baby may have some leakage because of poor tongue control. However, many infants with Down syndrome can successfully breast-feed. Obesity can become a problem for older children and adults. Getting plenty of activity and avoiding high-calorie foods are important. Before beginning sports activities, the child’s neck and hips should be examined. Behavioral training can help people with Down syndrome and their families deal with the frustration, anger, and compulsive behavior that often occur. Parents and caregivers should learn to help a person with Down syndrome deal with frustration. At the same time, it is important to encourage independence.
Adolescent females and women with Down syndrome are usually able to get pregnant. There is an increased risk of sexual abuse and other types of abuse in both males and females. It is important for those with Down syndrome to:
- Be taught about pregnancy and taking the proper precautions
- Learn to advocate for themselves in difficult situations
- Be in a safe environment
If the person has any heart defects or problems, check with the physician about the need for antibiotics to prevent heart infections called endocarditis.
Special education and training is offered in most communities for children with delays in mental development. Speech therapy may help improve language skills. Physical therapy may teach movement skills. Occupational therapy may help with feeding and performing tasks. Mental health care can help both parents and the child manage mood or behavior problems. Special educators are also often needed.
Where to find medical care for Down syndrome
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What to expect (Outlook/Prognosis)
These factors can contribute to a shorter life expectancy for people with Down syndrome. One study, carried out in the United States in 2002, showed an average lifespan of 49 years, with considerable variations between different ethnic and socio-economic groups. However, in recent decades, the life expectancy among persons with Down syndrome has increased significantly up from 25 years in 1980. The causes of death have also changed, with chronic neurodegenerative diseases becoming more common as the population ages. Most people with Down Syndrome who survive into their 40s and 50s begin to suffer from an Alzheimer’s disease-like dementia.
- Airway blockage during sleep
- Compression injury of the spinal cord
- Eye problems
- Frequent ear infections and increased risk of other infections
- Hearing loss
- Heart problems
- Gastrointestinal blockage
- Weakness of the back bones at the top of the neck