Tara Purcell 2.17.11
Mrs. Kenny/HLIV Genetic Disorders
There are many different problems that occur with the chromosomes of a living organism. In some cases, the effects can have a huge impact on a person's life. Trisomy 21 is one of these disorders. It is caused by a malfunction in the chromosomes during reproduction. When a baby is being made, the chromosomes pair off with each other, creating the genotypes of that organism. Even if one single chromosome is flipped or switched, it can cause severe mental and physical defects.
The study on Trisomy 21, which is more commonly called Down Syndrome, began in 1866 when physician John Langdon Down published an essay describing a group of children who were distinctly different from other children with mental retardation. It was first suggested that the cause of Down Syndrome might involve differences with chromosomes in the 1930s by two genetic researchers named Waardenburg and Bleyer. Then, in 1959, two independently working geneticists, Lejeune and Jacobs, discovered that the cause of this mental retardation was trisomy. Trisomy 21 is the triplication of the twenty-first chromosome. There are many indications of Trisomy 21 in humans, some being external and some being internal. People with Trisomy 21 may have an unusual facial appearance as well as inborn heart disease.
There are certain ways in which a doctor can detect that a child that may have Down Syndrome. There are many tests that can be performed on a woman during pregnancy. If it cannot be detected during pregnancy, a doctor can usually determine it by the distinctive facial features a person with Down Syndrome has. A karyotype, which is an observation of the chromosomes, will confirm the presence of the three paired chromosomes. There is no way to completely rid a person of this disorder. However, with the help of tutoring and therapy, a person with Down Syndrome can succeed in school and join the working world. There is...