Down Syndrome

General Illness Information


Medical Term:

Down Syndrome

Common Name: None Specified

Description: Down syndrome (Trisomy 21 ) is due to a chromosomal abnormality that  is associated with mental retardation of varying degrees and may be associated with abnormalities in many organs. Down Syndrome is usually diagnosed at birth on the basis of typical facial features.

The syndrome occurs in all races with equal frequency. Incidence is 1 in 1000 births but risk varies a great deal with mothers age. More than 20% of infants with Down syndrome are born to mothers over 35 years of age, yet older mothers bear only 7 to 8 percent of all children.

Most cases are identified at birth.

Causes: Cause unknown, but usually genetic. Down syndrome is a result of a chromosomal abnormality. In 90% of the cases it is due to an extra chromosome 21. This means that there are three chromosomes of the same kind (called Trisomy) instead of the normal two of a kind. Other chromosomal abnormalities account for the rest of the cases of Down syndrome. In 1/3 of cases, the extra chromosome comes from the father.

Prevention:

Obtain genetic counseling before starting a family-if there is a family history of Down Syndrome in either of the partners.

If over 35 years of age or with positive family history of Down Syndrome, request blood test (called Triple maternal Screen) which detects a certain protein called alpha- fetoprotein in mothers blood. This test is to be performed at 16-18 weeks pregnancy . Low levels of alpha-fetprotein indicate an increased risk of Down syndrome in the fetus: and in such cases, amniocentesis should be performed. Blood test is a very sensitive test and therefore, it frequently gives false positive readings. Amniocentesis is a more accurate test for detecting Down Syndrome in the fetus.

Signs & Symptoms

  • “Floppy infant” – reduced muscle tone. Tends to be placid- rarely cries;
  • Small or odd shaped head. Small chin depressed nasal bridge and increased swelling back of neck;
  • Small, low set ears and almond shaped eyes;
  • Small mouth and protruding tongue;
  • Small hands and single palmer crease;
  • Heart murmur. Congenital heart disease is seen in 35% of patients;
  • Thyroid dysfunction;
  • Hearing loss;
  • Retardation growth and development. Child never reaches full stature;
  • Varying degrees of mental retardation. Average IQ in a child with Down syndrome is about 50, compared with normal IQ of 100.

Risk Factors

  • Pregnancy in females under age 16 or over age 35. Risk increases with mothers age. At age 40, incidence is 1 in 40 births;
  • Family history of Down syndrome;
  • Mother’s exposure to drugs, radiation, chemicals or infections before pregnancy.

Diagnosis & Treatment

The diagnosis of Down syndrome can often be made before birth by doing the screening test- Triple maternal screening test (as mentioned under Prevention). This test is generally recommended in pregnant women over 35 years of age. Additionally, ultrasound scanning may help identify physical abnormalities in the fetus at 16 to 18 weeks gestation. After birth, diagnosis may be made from the physical characteristics. Diagnosis can be confirmed by testing infants blood for Trisomy 21.

General Measures:

  • Learn all you can about programs and resources in your community to help children with Down Syndrome;
  • Psychotherapy or counseling for the parents. Many parents blame themselves and need help to cope with unnecessary, harmful guilt;
  • Infant stimulation programs recommended;
  • Surgery to correct congenital heart or intestinal disorders;
  • Nursing home or group-home care, if home care is not feasible.

Medications:

Antibiotics for frequent, complicating infections. There is no medication to cure Down Syndrome.

Activity:

Encourage the child to be as active as possible (unless heart disease is present) in a protected environment.

Diet:

No special diet. Extra patience may be necessary in feeding an infant with Down Syndrome. Some have difficulty sucking or are not eager to eat.

Possible Complications :

  • Increased susceptibility to leukemia and thyroid disease;
  • Increased susceptibility to infections. Recurrent ear infection makes them prone to hearing problems;
  • Congestive heart failure caused by congenital heart abnormalities;
  • Alzheimer’s disease in 1/3 of patients over age 40;
  • Vision problems because of changes in the corneas and lenses.

Prognosis

Special education and training allow many children with Down Syndrome to lead happy, loving and useful lives. Life expectancy is reduced. Few persons with Down Syndrome reach age 40.

Other

Nothing Specified.