Thursday, January 2, 2014

A Step Forward in the Genetic Treatment of Down"s Syndrome:

Ordinarily, during the reproduction process, the egg cell and the sperm cell start out with 46 chromosomes. The egg and sperm each undergo cell division (a process through which the 46 chromosomes are divided in half), and the egg and the sperm cells each end up with 23 chromosomes. Consequently, when a sperm with 23 chromosomes fertilizes an egg with 23 chromosomes, the baby ends up with a complete set of 46 chromosomes (half coming from the father"s sperm and half from the mother"s egg).

From time to time, an error may occur when the chromosomes are being divided in half, and an egg or sperm cell keeps both copies of the #21 chromosome instead of just one copy. As a result, if this egg or sperm is fertilized, the baby ends up with three copies of the #21 chromosome. This is called "trisomy 21" or Down syndrome. The features of Down syndrome result from having an extra copy of chromosome 21 in every cell in the body. Ninety-five percent of Down syndrome results from trisomy 21.

People with this condition have an increased susceptibility to infection, while children with Down"s Syndrome have a 10 to 20 fold increased risk of developing leukemia, and 10 to 15% of babies with Down syndrome have a severe heart defect that requires surgical intervention during the first few months of life. Fortunately, in recent times, we have made great advancements in the fight against this condition.

Learn about these breakthroughs at:


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