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Causes, Symptoms and Diagnosis of Down Syndrome

Down syndrome is a genetic disorder where typically there are 47 chromosomes instead of the 46 seen in normal people. Down syndrome is the most common form of cognitive impairment. It causes mild to moderate learning disabilities and developmental delays. People with Down syndrome are noticeable due to the characteristic facial features like flattened nose, short neck, and eyes slanting upwards.

Fast Facts about Down Syndrome

  • Down syndrome is a genetic disorder with typically 47 chromosomes instead of 46 chromosomes. The different types of Down syndrome are Trisomy 21, mosaicism, and translocation.
  • A woman is at risk of having a baby with Down syndrome if she already has a child with the condition, or if she is over 35 years of age.
  • People with Down syndrome have characteristic facial features of flattened nose, short neck, eyes slanting upward, stubby fingers and only one crease in the palm, poor muscle tone, and developmental and mental delays. They may also have cardiac problems, gastrointestinal blocks, constipation, hearing loss, and mental problems.
  • Down syndrome can be diagnosed during the early stages of pregnancy for example by withdrawing amniotic fluid for testing abnormalities. The diagnosis can also be made by the physical appearance of the infant.
  • There is no treatment for Down syndrome, but it can be managed by early interventions.
  • Down syndrome cannot be prevented. Women can get genetic counseling and learn about their risk of having a baby with Down syndrome.
  • People can live successfully with the condition. Behavioral therapy can benefit the person with Down syndrome and the family to deal with anger and frustration. They must be educated about sex to avoid sexual abuse.

Types of Down Syndrome

  • Trisomy 21 – seen in most cases of Down syndrome.
  • Mosaicism – a rare form of Down syndrome. In children, some cells have an additional copy of chromosome 21.
  • Translocation – an uncommon form of Down syndrome occurs when a portion of chromosome 21 gets translocated to another chromosome before or during conception. In this unusual form of Down syndrome, the two copies of chromosome 21 are present along with additional material attached to the translocated chromosome.

Causes of Down Syndrome

Normal human cells contain 23 pairs of chromosomes, where one chromosome in each pair comes from the father and another from the mother. In the case of Down syndrome, abnormal cell division causes extra genetic material from chromosome 21 to form an extra chromosome or segment, which causes characteristic features and developmental delays. Down syndrome is not genetically inherited, but caused by faulty cell multiplication during the development of the fetus.

Risk Factors for Down Syndrome

Some of the risk factors for having a baby with Down syndrome are:

  • Maternal age – with advancing age a woman’s chance of having a child with Down syndrome increases because older eggs are at a greater risk of faulty chromosome division
  • Have one child with Down syndrome – a woman with one child of Down syndrome has a 1 percent chance of having a second child with Down syndrome

Both parents can pass the genetic translocation to their children

Symptoms of Down Syndrome

Children with Down syndrome are easily recognizable because of their distinct facial features including small head, short neck, eyes slanting upward, flattened nose, unusually shaped ears, relatively stubby fingers, poor muscle tone, single crease in the palm of the hand, and small mouth. Infants with Down syndrome have major developmental delays. Common mental and social challenges in children with Down syndrome are:

  • Mental retardation
  • Birth defects of the heart including atrial septal defect or ventricular septal defect
  • Cataracts – children with Down syndrome often need glasses
  • Hearing problems
  • Hip problems and risk of dislocation
  • Constipation
  • Sleep apnea
  • Hypothyroidism

Diagnosing Down Syndrome

The infant is diagnosed by its initial appearance. Blood tests are done to verify the extra chromosome before diagnosing Down syndrome. Other tests done to confirm Down syndrome are echocardiogram to check for heart defects, electrocardiogram, and x-rays of the chest and gastrointestinal tract.

Down syndrome can be diagnosed before the birth of the child by a procedure called amniocentesis. Between 16 and 20 weeks of pregnancy, amniotic fluid is taken and analyzed for chromosomal anomalies. Consult your doctor about the risks and benefits of amniocentesis before signing up for the procedure.

Treatment Options for Down Syndrome

While there is no treatment for Down syndrome, the condition can be managed by early interventions. Surgical interventions can correct gastrointestinal blocks and heart defects.

Behavioral training is particularly beneficial for people with Down syndrome. The training helps the families handle the compulsive behavioral problems like frustration and anger. Adolescent females with Down syndrome can become pregnant; therefore, they must be educated about pregnancy and necessary precautions. Sexual and physical abuse is common in males and females with Down syndrome. They must be in a secure environment and learn to fend for themselves if problems arise.

In most communities, children with developmental delays can get special training and education. Language skills can be homed with speech therapy. Occupational therapy and physical therapy help improve movement skills.

When the infants with Down syndrome are breast-fed, they must be fully awake as they have poor tongue control and can gag easily. In older children and adults, obesity can be a problem if they do not get enough exercise. They will benefit from a low-calorie diet.

Prevention of Down Syndrome

Down syndrome cannot be prevented, however, if a woman knows she is at high risk for having a baby with Down syndrome, she can consult a genetic counselor who can help the family by explaining the options of prenatal testing available to them. If the woman has a child with Down syndrome, she is at risk for having another baby with Down syndrome. If she is over age 35, her chances of a high-risk pregnancy are higher. Amniocentesis, chorionic villus sampling, and translucency ultrasound are done during the first few months of pregnancy to test for Down syndrome.

Coping with Down Syndrome

Many people with Down syndrome can live independently and manage their lives well although they may experience physical and mental constraints. Children born with heart problems must get early interventions. Mental challenges differ from person to person with Down syndrome. Some complications that may arise due to Down syndrome are:

  • Spinal cord compression injury
  • Endocarditis
  • Eye problems
  • Increased frequency of ear infections and hearing loss
  • Cardiac problems
  • Gastrointestinal block

Families must consult with their health care providers and decide if they need to arrange for special education and training to manage their child’s condition.

Where to Get More Information and Support:
National Down Syndrome Society
National Association for Down Syndrome