History

Down syndrome named after the physician John Langdon Down, who in 1862 characterized Down syndrome as a distinct form of mental disability and later obtain a more publicized report in 1866.  This characterization came after he studied physical similarities between children with the then undiagnosed Down syndrome. Public opinion of Down syndrome was tied to racism and colonialism up to the 1970’s.  Now as of the twentieth century Down syndrome is the most recognized form of mental disability. Approximately 1 out of every 733 children is born with Down syndrome. This statistic is closely related to the age of the mother, however no reason has been identified for this correlation.

Following the identification of Down syndrome in 1862,  the reason for the occurrence of the syndrome remained a mystery.  Not until the french geneticist Jerome Lejeune in 1959 did we know what the cause of the most recognized mental disability.  Lejeune found that this syndrome occurred from a trisomy on chromosome 21.  A trisomy is a genetic anomaly where there are three copies of a chromosome rather than the customary two.  This results in 47 chromosomes instead of the normal 26, in particular for Down Syndrome this extra chromosome comes on the 21st. Despite this it still remains a conundrum to modern day genetics why this occurs. Presently, since the great prevalence of Down syndrome and its origin on chromosome 21, the chromosome is the second most heavily researched.
The genetic abnormality of the trisomy of chromosome 21 leads to the physical and mental conditions, that John Langdon Down used in his identification. The common IQ of a child with DS is 50 compared to that of a normal child being 100.  Several of the physical features are common in almost all DS cases, these are microgenia and macroglassia.  Microgenia being an untypical small chin and macroglassia being an oversized tongue. Both are seen in nearly all DS patients.  Additionally, along with these physical and mental afflictions, children with DS have increased health risks for congenital heart defects, gastroesophageal reflux disease, and thyroid dysfunctions.  
As a result of the current status of knowledge we have of DS and the early screenings during pregnancies, the abortion rates after diagnosis of Down syndrome have grown.  In a study done in the United Kingdom, an estimated 91 to 93 percent of pregnancies where the fetus is diagnosed with DS the parents opt of abortion.  Despite this, a study by the CDC (Center for Disease Control and Prevention) in the United States, has found that the number of children born with DS has risen by nearly one-third in the last three decades, even though the termination of these pregnancies is more prevalent.  This proliferation of children with DS has corresponded with the age in which women are now having children. Since 1991 the number of women having children from 36 to 39 has increased by thirty six percent. Furthermore, among women 40 to 44 the number has risen by seventy percent.
 Although early screening hinders a larger ascension of children born with DS. The statistics of children born with DS, is expected to rise. A great deal of these children will suffer from the health conditions that will lead to premature death.  Nevertheless, progressive quality health care, in recent years has assisted in enabling the amelioration of the health of Down syndrome children. Explanation of why the trisomy of chromosome 21 manifests is yet to be uncovered. In spite of that, new research is being unearthed every day and one day the reason for the affliction of millions of children will be established.