Question

How can Down syndrome be detected during pregnancy?

Answer 1

Down's syndrome is an abnormality in chromosomal count that leads to congenital genetic disorder. Prenatal diagnostic tests are available to detect this.

Explanation:

Chromosome 21 of human genome is represented thrice in Down's syndrome affected children. Thus it is trisomy of 21 chromosome and total number of chromosomes in each body cell is 47 instead of normal 46 (2n+1 condition).

This chromosomal abnormality could be easily detected by studying cell division in harvested embryonic cells. Such cells are collected by taking out a sample of amniotic fluid from pregnant mother's uterus. This process of amniotic fluid test is called amniocentesis . It helps in detecting disorders that the embryo may suffer from due to abnormality in chromosomal structure or number.

Chorionic villi sampling is another method to detect chromosomal abnormality in embryo.