Lack of information results in more cases of Down Syndrome

Every 20 minutes, a child is born in India with Down Syndrome -- a disease characterised by mental and physical retardation. This happens despite the fact that a blood test in the early stages of pregnancy can help detect the disease. Lack of knowledge among couples about genetic counselling has resulted in the birth of tens of thousands of Down syndrome-affected children in the country, say experts.

According to a report prepared by the genetic unit of the department of pediatrics in the All India Institute of Medical Sciences, all pregnant women should undergo a blood test between 15 and 18 weeks of pregnancy to test maternal serum for an increase in a hormone released by the placenta, the human chorionic gonadotropin, and alpha fetoprotein, a substance produced by the foetus. An ultrasonography can also help reveal the presence of Down Syndrome.

If the foetus has Down Syndrome, an abortion should be done within 20 weeks of pregnancy, according to experts.

Once called mongolism, it was later named after Dr Langdon Down, who first described the symptoms, following a furore over the political incorrectness of the term 'mongolism'. In the condition, the child has an extra chromosome (the 21st) in every cell. Such children have 47 chromosomes in their cells instead of the usual 46 chromosomes and are often born to older mothers. About one in 2,000 children born to younger women have the syndrome, rising to one in 40 for women over 40. The problem has increased in recent years since more women are having children later.

According to experts, analysis of data in India shows that the incidence of Down Syndrome is about one for every 1,000 births. But because of the large population and high birth rate, one infant with Down syndrome is born every 20 minutes.

The report says the state of children with Down Syndrome is much better than those with other forms of mental handicap. Though found to have a tardy mental development, the former group is able to sit, walk and speak, though they begin doing so later than normal children.

It says about such children are more prone to infections of the upper respiratory tract as well as pneumonia. Therefore these children should be kept away from those who have fever, cold or cough.

When a child with Down Syndrome is born, the risk of recurrence in subsequent pregnancies is only about one per cent. However, when the maternal age at conception is less than 30 years, about five per cent of cases with Down Syndrome has a different chromosomal abnormality called translocation.

If translocation is detected, the risk of recurrence is about five to ten per cent higher. In such cases the geneticists should be consulted and the parents' chromosomes studied for abnormalities.

Down Syndrome can be prevented in high risk situations such as advanced maternal age by determining the chromosomes of the unborn baby. This is done by examining the cells in the amniotic fluid or by other methods.

A child with Down Syndrome has a characteristic upward slant of the eyes, a flat face, a small head and ears, weak muscles and short and broad hands with curved little fingers. The bridge of the nose is flattened, the mouth is often held open because of a large, protruding tongue that is furrowed and lacks the central fissure. The hands are short and broad, with a single palmar crease (called the simian crease). The fingers are short, with the fifth finger being curved inwards and often having only two bones instead of the usual three. The feet have a wide gap between the first and second toes. Congenital heart disease is found in about 35 per cent of all affected children.

A child with Down Syndrome is also susceptible to acute leukemia. That, the heart trouble common to the afflicted and what appears to be an accelerated aging process causes death to occur in the forties or fifties.

Early detection of the problem can do much to alleviate the problem, the experts said, adding that a few tests, especially in the more vulnerable people, could help avoid problems later.

EXTERNAL SITES:
The Merck manual: Down's syndrome
Maternal Serum Alpha-fetoprotein Testing