Cause and History
Down syndrome, also called Trisomy 21, is a chromosomal disorder which occurs when part or all of am extra 21st chromosome is present. It affects 1 in 800 babies born. It occurs in human populations though has been found in chimpanzees and mice. The chances of having a child with down syndrome increases by the age of the woman conception. The chance for a woman under 35 is 1 in 900, and goes up to I in 350 at 35 and by the age of 40 1 in 100.
It was first noted by John Langdon Down who thought it was a form of mental disability, in 1862 though more published in 1866. it became the most recognized form of mental disability, and those effected where put in institutes. 33 of the then 48 states in America, started sterilizing down syndrome individuals to stop them from reproducing and therefore creating more affected individuals.
Though further on they realised that reoccurrence was very rare and they thought it was then caused by a combination of inheritable factors, other theories included that it was obtained by injuries during birth.
It was in 1959 that after karyotype techniques had been discovered and abnormalities in chromosomes could be noted that Jerome Lejuene discovered that Down syndrome was caused by the extra 21st chromosome.
Cause and History
Down syndrome, also called Trisomy 21, is a chromosomal disorder which occurs when part or all of am extra 21st chromosome is present. It affects 1 in 800 babies born. It occurs in human populations though has been found in chimpanzees and mice. The chances of having a child with down syndrome increases by the age of the woman conception. The chance for a woman under 35 is 1 in 900, and goes up to I in 350 at 35 and by the age of 40 1 in 100.
It was first noted by John Langdon Down who thought it was a form of mental disability, in 1862 though more published in 1866. it became the most recognized form of mental disability, and those effected where put in institutes. 33 of the then 48...