What is Down Syndrome

December 17, 2018

Down syndrome is a disease that manifests because of a genetic abnormality that affects the mental capabilities and physical appearances of an affected person. Individuals with this condition will maintain various degrees of medical and physical issues. Some persons with the disease are able to lead relatively normal lives while others need persistent medical treatment. It occurs in 1 in 800 newborns and is said to be more common with increasing maternal age. The disease cannot be prevented; however, it can be diagnosed in the uterus, before the baby is born. There is still a lot of controversy surrounding the ramifications of genetic testing for Down syndrome. It has been discovered that an estimated 90-93% of women pregnant with a child with Down Syndrome had the pregnancy terminated once this was deduced using available methods of genetic testing.

The outlook for children with Down’s syndrome has greatly improved in the last decade. The average life span for a person with Down syndrome was 25 years in the 1980′s it has now increased to 49 years of age since then. Individuals with the disease will often have significantly lower levels of fertility especially males who are generally infertile with only 3 reported cases of a male with Down syndrome maintaining the ability to procreate. Most children with Down syndrome will also show significantly lowered cognitive abilities. However, with proper medical treatment, family support and vocational training the child with down syndrome can overcome some of his or her limitations.

What Causes Down Syndrome
The disease as mentioned before is induced by a genetic irregularity. An unaffected individual will have 46 chromosomes, 23 of which will be inherited from either parent. When an individual has Down syndrome, he or she will have an additional chromosome, that is 47 chromosomes in total. This chromosomal abnormality manifests as a result of an extra copy of the 21st chromosome. The effect of the extra copy will be slightly different among the afflicted individuals.

The disease cannot be prevented and is considered a spontaneously occurring manifestation. However, women over the age of 35 are at a much heightened risk of conceiving a child with Down syndrome. The risks for different groups are exhibited below:

Women who are 25 years of age will have a 1in 1,250 risk of having a baby with Down Syndrome.
Women who are 30 years of age will have a 1 in 1000 risk of having a baby with Down Syndrome.
Women who are 35 years of age will have a 1in 400 risk of having a baby with Down Syndrome .
Women who are 40 years of age will have a 1 in 100 risk of having a baby with Down Syndrome .
Women who are 45 years of age will have a 1 in 30 risk of having a baby with Down Syndrome .
The likelihood of having a child with Down’s Syndrome may also be related to a familial genetic irregularity. An individual who has a balanced translocation will not show any signs of down syndrome but will have a heightened risk of having a child with translocation Down syndrome. The approximate risk is 1 in 5 for the female carrier and 1 in 50 for a male carrier of the defect. In some cases where there is no unattached copy of chromosome 21 the carrier’s children will all be subject to Down’s Syndrome. The affected parent is subsequently deemed a translocation carrier. This specific type of Down’s syndrome is believed to occur in 2-3% of all Down’s syndrome cases.

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