Down SyndromeTrisomy 21 is caused, as its name suggests, by the triplication of the 21st chromosome. Genes, which, simplified, contain the blueprints of our cellular structure, are grouped along rod-shaped 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, cells usually contain not 46, but 47 chromosomes. This excess genetic material, in the form of extra genes along the 21st chromosome, results in DS. The estimated incidence of Down syndrome is between 1 in 1,000 and 1 in 1,100 live births. Every year, approximately 3,000 to 5,000 children are born with this chromosomal disorder. It is estimated that approximately 250,000 families in the United States are affected by DS. (Berg, 614) This article will discuss a more detailed description of the pathophysiology of Down syndrome, as well as the discovery, possible causes, physical characteristics, associated conditions, possible treatment, electroneurodiagnostic corollaries and problems psychosocial. Down syndrome has been discussed in art, literature and science for centuries. One of the most interesting is the “Changeling” in Gaelic myth. It was believed that when a child was born with the dysmorphic features now associated with DS, namely epicanthal folds, simian folds, small ears, etc., an elf or evil spirit had replaced the child who was believed to be the them by the offspring of a mischievous one. creature. However, it was not until 1866 that a physician named John Langdon Down published an essay in England in which he described a set of children with common characteristics distinct from other children with mental retardation. Down was director of an asylum for mentally retarded children in Surrey, England, when he first made the distinction between moronic children (who later suffered from hypothyroidism) and what he called "Mongoloids." Down based this unfortunate name on the idea that these children resembled Mongols, who were then thought to have arrested development. This ethnic slur was criticized in the 1960s by Asian genetic researchers, and the term was dropped from scientific usage. Instead, the condition was called "Down 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 "Down's" in Europe..