Understanding Down Syndrome

5 Pages 1264 Words

The disability of Down syndrome was first identified back in 1866, by a physician named John Langdon Down who was the superintendent of an asylum for children with mental retardation in Surrey, England. He published an essay, describing children with the same features as being mentally retarded. He thought the children to have an arrested development. In the 1960’s the term mentally retarded was dropped and was then called Down’s syndrome because it was an ethnic insult to Asian researchers. In the 1970’s an American revision of the term was changed to Downs syndrome. Whereas in the UK and some places in Europe the disorder is still known as Down’s. In the first part of the twentieth century, people were not sure what caused Downs syndrome. In the 1930’s two researchers, named Waardenburg and Bleyer were the first to predict that maybe Down syndrome was caused because of chromosomal abnormalities. By 1959 two independent researchers, Jerome Lejeune and Patricia Jacobs determined the cause of Down syndrome as being trisomy (triplication) of the 21st chromosome. They discovered that cases of Down syndrome were due to two problems of translocation and mosaicism.

The defect of chromosomes in a person causes Down syndrome. Chromosomes are thread like structures made up of DNA and other proteins. Chromosomes carry genetic information that is needed for our cells to develop. In a normal human being, each chromosome divides into two. The two different chromosomes go to two different spots in the cell. Rarely, but it does happen to where the chromosome wont divide, but stays as one. Then the whole pair goes to the same part of the cell. This makes an uneven balance with the cells. One cell will have 22 chromosomes whereas the rest of the cells will have 24 chromosomes. This is known as nondisjunction. If a male or a female has non-normal chromosomes and mates with a person who has normal chromosomes, 95% of all c...