Down syndrome, a chromosomal disorder, is the most frequent genetic cause of mild to moderate mental retardation in the United States. An article in the February 28, 2001, issue of The Journal of the American Medical Association discusses whether an ultrasound examination of the fetus during pregnancy is an accurate screening test for Down syndrome. The authors conclude that ultrasound examinations are not practical to use for this purpose.
What Is a Chromosome?
A chromosome is a package of genetic material found in the center (nucleus) of every cell. Human cells normally contain 23 pairs of chromosomes, half of which are inherited from each parent. Each chromosome pair is designated by a number, except for the sex chromosomes, which are designated by X and Y.
What Causes Down Syndrome?
Down syndrome occurs when one of the reproductive cells from the parents that combine at fertilization contains extra material from chromosome 21. Individuals with Down syndrome usually have three copies of chromosome 21 (Trisomy 21) instead of two copies.
The risk of having a baby with Down syndrome increases with increasing age of the mother at conception. You can discuss with your doctor the possibility of receiving genetic counseling and prenatal screening for Down syndrome. Genetic counseling helps you and your partner learn about the benefits and risks of prenatal screening.
Most individuals who have Down syndrome have intelligence quotient (IQ) scores in the mild to moderate range of retardation. Children with Down syndrome need to be in special educational programs that give them a good environment for learning and that keep pace with their intellectual capabilities. Early intervention with the help of special educators, speech therapists, occupational therapists, and social workers can provide the stimulation and encouragement that can make a difference in the life of a person with Down syndrome.
Medical Problems Associated With Down Syndrome
Children who have Down syndrome have the same health care needs as other children, but they also need extra care. Some of the conditions that may be associated with Down syndrome include:
· Heart defects
· Hearing problems
· Eye problems
· Seizure disorders
· Stomach or intestinal problems
· Trouble swallowing
· Thyroid problems
· Bone and joint problems
· Leukemia