- What is Down's syndrome?
- What are its characteristic features?
- How is it diagnosed?
- Can it be diagnosed before a baby is born?
- What is the treatment?
What is Down's syndrome?
Down’s syndrome, also known as “mongolism”, a term no longer used due to its racial connotations, is an abnormality of the chromosomes. Also called Trisomy 21, it is caused due to erroneous disjunction of chromosomes during cell division. Chromosomes are present in all cells of the body and occur in pairs – one coming from each parent. The chromosomes carry information coded in genes, that controls the various functions of the cell. Each cell has 23 pairs of chromosomes. In Down’s syndrome, the chromosomes fail to separate fully at the time of cell division, resulting in an extra chromosome in the sperm or egg. When any of these abnormal gametes or sex cells combines with a normal mate, the resulting fertilised egg will have an abnormal number of chromosomes.
What are its characteristic features?
Children with Down’s syndrome have a very characteristic physical appearance with the following features:
- Smaller than normal head or microcephaly.
- Broad forehead, flattened nose and protruding tongue.
- Upward slanting eyes, which may have a filmy fold in the inner corner.
- Short, broad hands with short fingers. The palm may have just one crease rather than many called a simian crease.
- These children have varying degrees of intellectual retardation.
Besides these apparent physical abnormalities, these children may have other birth defects of the heart, oesophagus (food pipe) or gastro-intestinal tract, which may have to be treated surgically.
How is it diagnosed?
The characteristic appearance of the baby may make the paediatrician suspect the disorder at birth. The diagnosis can be confirmed by performing a blood test in which the chromosomes present in the cells can be counted. This test is called a chromosome analysis. Other associated birth defects may require further tests for diagnosis. Inability at birth to pass a tube from the mouth to the stomach may indicate an oesophageal obstruction, while excessive vomiting may be due to gastrointestinal defects. X-rays and ECG may be done to determine if any abnormality of the heart is present
Can it be diagnosed before a baby is born?
Tests can now be done on a baby growing in the womb of the mother (foetus) to find out if he has Down’s syndrome. Cells from the foetus are taken and a chromosome analysis is done. In case it is diagnosed, the pregnancy may be terminated. This test can be done as early as 10 to 14 weeks of pregnancy.
What is the treatment?
Since Down’s syndrome is a condition and not a disease, it cannot be treated or cured. The child’s average mental age even after complete maturity is attained, is rarely more than 8 years. However, the child can be helped to adapt to the social conditions by way of integration. Many educational institutions catering specifically to the needs of special children are operating in the country. These provide academic and vocational education to these children to make them functional members of the society.
Clinical conditions occurring in conjunction with Down’s syndrome have to be medically treated. Since specific conditions like epilepsy often occur in a child with this condition, medications can be given to reduce the accompanying symptoms. The child can also be treated for disruptive behaviours that are a result of the intellectual impairment, and also for the increased susceptibility to infections. Other associated disorders like visual and hearing impairment are also potentially treatable.
