Trisomy 21 Down Syndrome Essay Example For Students

Trisomy 21 Down Syndrome Essay Trisomy 21 is caused, as the name suggests, by the triplication of the 21st chromosome. Genes which, simplified, contain the blueprints for our cellular structure, are grouped along rod-like structures called chromosomes. Normally, the nucleus of each cell contains 23 pairs of chromosomes, half of which are inherited from each parent. In Down syndrome (DS), however, the cells usually contain not 46, but 47 chromosomes. This excess genetic material, in the form of additional genes along the 21st chromosome, results in DS. The estimated incidence of Down syndrome is between 1 in 1,000 to 1 in 1,100 live births. Each year approximately 3,000 to 5,000 children are born with this chromosome disorder. It is believed there are about 250,000 families in the United States who are affected by DS. (Berg, 614) Discussed in this paper will be a more detailed description of the pathophysiology of Down syndrome, as well as the discovery, possible causes, physical features, associated conditions, possible treatment, electroneurodiagnostic corollaries, and psychosocial issues. Down syndrome or Trisomy 21 has been alluded to in art, literature and science for centuries. One of the more interesting of these is the Changeling in Gaelic myth. We will write a custom essay on Trisomy 21 Down Syndrome specifically for you for only $16.38 $13.9/page Order now It was believed that when a child was born with the dysmorphic characteristics now associated with DS i.e. epicanthal folds, simian creases, small ears etc., an elf or evil spirit had replaced the infant that was meant to be theirs with the offspring of a mischievous creature. However, it wasnt until 1866, that a physician named John Langdon Down published an essay in England in which he described a set of children with common features who were distinct from other children with mental retardation. Down was superintendent of an asylum for children with mental retardation in Surrey, England when he made the first distinction between children who were cretins (later to be found to have hypothyroidism) and what he referred to as Mongoloids. Down based this unfortunate name on his notion that these children looked like people from Mongolia, who were thought then to have an arrested development. This ethnic insult came under fire in the 1960s from Asian genetic researchers, and the term was dropped from scientific use. Instead, the condition became called Downs syndrome. In the 1970s, an American revision of scientific terms changed it simply to Down syndrome, due to the insinuation of ownership caused by the possessive apostrophe, although it is still called Downs in Europe. The causes of DS were much speculated over during the first part of the twentieth century. The first to speculate that Down syndrome might be chromosomal in nature were Waardenberg and Bleyer during the 1930s. However it wasnt until 1959 that Jerome Lejeune and Patricia Jacobs, working independently, first determined the cause to be trisomy (triplication) of the 21st chromosome. To understand the pathophyisology of Trisomy 21 you must first understand the basic structure of chromosomes. Chromosomes are thread-like structures composed of DNA and other proteins. They are present in every cell of the body and carry the genetic information needed for that cell to develop. Genes, which are units of information, are encoded in the DNA. Human cells normally have 46 chromosomes, which can be arranged in 23 pairs. Of these 23, 22 are alike in males and females; these are called the autosomes. The 23rd pair are the sex chromosomes (X and Y). Each member of a pair of chromosomes carries the same information, in that the same genes are in the same spots on the chromosome. However, variations of that gene (alleles) may be present. (Example: the genetic information for eye color is a gene; the variations for blue, green, etc. are the alleles. .uae77199ac9d00f2b3268239334c34952 , .uae77199ac9d00f2b3268239334c34952 .postImageUrl , .uae77199ac9d00f2b3268239334c34952 .centered-text-area { min-height: 80px; position: relative; } .uae77199ac9d00f2b3268239334c34952 , .uae77199ac9d00f2b3268239334c34952:hover , .uae77199ac9d00f2b3268239334c34952:visited , .uae77199ac9d00f2b3268239334c34952:active { border:0!important; } .uae77199ac9d00f2b3268239334c34952 .clearfix:after { content: ""; display: table; clear: both; } .uae77199ac9d00f2b3268239334c34952 { display: block; transition: background-color 250ms; webkit-transition: background-color 250ms; width: 100%; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #95A5A6; } .uae77199ac9d00f2b3268239334c34952:active , .uae77199ac9d00f2b3268239334c34952:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #2C3E50; } .uae77199ac9d00f2b3268239334c34952 .centered-text-area { width: 100%; position: relative ; } .uae77199ac9d00f2b3268239334c34952 .ctaText { border-bottom: 0 solid #fff; color: #2980B9; font-size: 16px; font-weight: bold; margin: 0; padding: 0; text-decoration: underline; } .uae77199ac9d00f2b3268239334c34952 .postTitle { color: #FFFFFF; font-size: 16px; font-weight: 600; margin: 0; padding: 0; width: 100%; } .uae77199ac9d00f2b3268239334c34952 .ctaButton { background-color: #7F8C8D!important; color: #2980B9; border: none; border-radius: 3px; box-shadow: none; font-size: 14px; font-weight: bold; line-height: 26px; moz-border-radius: 3px; text-align: center; text-decoration: none; text-shadow: none; width: 80px; min-height: 80px; background: url(https://artscolumbia.org/wp-content/plugins/intelly-related-posts/assets/images/simple-arrow.png)no-repeat; position: absolute; right: 0; top: 0; } .uae77199ac9d00f2b3268239334c34952:hover .ctaButton { background-color: #34495E!important; } .uae77199ac9d00f2b3268239334c34952 .centered-text { display: table; height: 80px; padding-left : 18px; top: 0; } .uae77199ac9d00f2b3268239334c34952 .uae77199ac9d00f2b3268239334c34952-content { display: table-cell; margin: 0; padding: 0; padding-right: 108px; position: relative; vertical-align: middle; width: 100%; } .uae77199ac9d00f2b3268239334c34952:after { content: ""; display: block; clear: both; } READ: April, 1985 and we were driving away from civilization towards the untamed, natural and beautiful Essay) Human cells divide in two ways. The first is ordinary cell division (mitosis), by which the body grows. In this method, one cell becomes two cells, which have the exact same number and type of chromosomes as the parent cell. The second method of cell division occurs in the ovaries and testicles (meiosis) and consists of one cell splitting into two, with the resulting cells having half the number of chromosomes of the parent cell. So, normal eggs and sperm cells only have 23 chromosomes instead of .