Down Syndrome - Causes, Symptoms, Diagnosis and Prevention

An Insight Into Down Syndrome

Dr.Bharat Parmar profile Authored by Dr.Bharat Parmar on 12 Feb 2014 - 14:31.
Down Syndrome
Down syndrome is a condition of lifelong mental retardation or delayed mental development caused as a consequence of genetic abnormality. Severity of the developmental problems may range from mild or moderate to severe. It is a most prominent genetic disorder which leads to learning disabilities in many children. Down syndrome is the most common chromosome abnormality among human beings, occurring in one/1000 babies, born each year.
Normally, human cells contain 23 pairs of chromosomes, each with two copies. Abnormal cell division in 21st chromosome results in excess production of genetic material. The presence of excessive genetic material leads to retarded or delayed development features.
The three genetic variations responsible for Down Syndrome are:
  • Trisomy 21: Having 3 copies of chromosome 21
  • Mosaic: Having some cells with excessive copies of chromosome 21
  • Translocation: Having a part of chromosome 21attached to another chromosome
Along with the significantly retarded growth, some common symptoms of Down Syndrome are:
  • Abnormal facial appearance
  • Small size head
  • Abridged neck
  • Bulged tongue
  • Slanting eyes
  • Abnormal shape of ears
  • Weak muscle tone
  • Comparatively short hands and figures
  • Abnormally excessively flexible
Experts have recommended various tests during pregnancy to assess the risk of Down Syndrome. Although these tests are not accurate, they can help take decisions about advanced diagnosis. In the first trimester a combination of tests in two steps, during week 11 to 13 of pregnancy are given. These tests include:
Blood Tests: To assess the presence of abnormal levels of pregnancy associated plasma proteins and human chronic gonadotropin hormone which indicates abnormality in foetus.
Nuchal Translucency Rest: It is a process of taking ultrasound to measure the neck (backside) of foetus.
Diagnosis involves the following tests:
Amniocentesis: After 15th week of pregnancy, a sample of the amniotic fluid surrounding the foetus is assessed to find out chromosomal defect.
Placenta cells of the mother are extracted and used to assess the foetal chromosomes.
Percutaneous Umbilical Blood Sampling (PUBS) - Blood from veins of the umbilical cord is taken out and examined for chromosomal defects.
Some prominent risk factors include:
  • Older maternal age - Conceiving after the age of 35 and later, increases the risk of having a child with genetic abnormality
  • Having a child with existing Down Syndrome
  • Hereditary - Having Down Syndrome family history
Children with Down Syndrome may develop diverse complications as they get older. Some common complications are:
  • Cardio vascular problems
  • Blood and bone marrow cancer
  • Susceptibility to various infections
  • Memory loss and seizures
  • Disturbed sleep
  • Excessive weight gain
  • Thyroid problems
  • Premature aging
  • Flawed vision
  • Unexpected menopause in early age
As this disorder is associated with diverse range of disabilities, it requires excessive care and specialized programs for the child, which includes special educators to teach the language, social behavior, daily activities and improve motor skills.
In addition to these approaches, medical experts’ team care is important. For better care, expert team should include pediatric cardiologist, speech therapist, neurologist, gastro specialist, audiologist and other experts as per need.
Although Down Syndrome cannot be prevented, you may consult your doctor during pregnancy to get tested for the risk of having it.  If a mother or father has the disorder, the risk passing it to the next generation is higher.
  • If the male partner is the carrier, the risk is about 3%.
  • If the female partner is the carrier, the risk ranges between 10 % and 15%.
A periodical gynecological test done during pregnancy to identify any such disorders can go a long way.
*Disclaimer This is not medical advice. The content is for educational purposes only. Please contact your doctor for any health care issues.