The name of the disorder is Down’s Syndrome or more scientifically known as Trisomy 21. Down’s syndrome is characterized by several of the following: broad flat face; up-slanted eyes, sometimes with an inner epicanthal fold; low-set ears; small nose and enlarged tongue and lips; sloping under chin; moderate to sever mental retardation; heart or kidney malformations or both; and abnormal dermal ridge patterns on fingers, palms, and soles. The frequency of giving birth to a child, male or female, with the congenital disorder is 1 per 650 to 1000 births. The risk increases as the maternal age increases. For example, the risk of having a live born with Down syndrome at maternal age of 30 would be 1 in 1, 000 and at maternal age of 40 would be 9 in 1, 000. Down’s syndrome is the first autosomal chromosome disorder to be described in man.
If a sperm or egg with an abnormal number of chromosomes merges with a normal mate, the resulting fertilized egg will have an abnormal amount of chromosomes. One cell has two 21 st chromosomes instead of one; so the resulting fertilized egg has three 21 st chromosomes. There are 47 chromosomes in most cells, rather than the normal 46. Including the Human Genome Database, researchers are mapping out the full structure of the chromosome because of the small size of the 21 st chromosome and its association with Down syndrome. They are focusing on trying to identify genes and their effects when and where they are over expressed. Currently, there are no cures.
The Essay on Genetic Disorders 3
... same type of chromosome and another gamete receives no copy. There is a correlation of Down syndrome with maternal age, the hypothesis ... and possible means of detection and/or prevention. One lethal disorder inherited as a recessive allele is Tay-Sachs disease. ... the offspring will have an abnormal chromosome number.Down syndrome is usually the result of an extra chromosome, so that each body cell ...
Severe mental retardation requires special training. Safety is frequently the concern that requires a change in living arrangements and, if no specialty care programs are available, may require admission to a nursing facility.
