No.
yes
it is the most popler up your but
Down's syndrome is the most common.
No.
Caucasian
Down syndrome
Down's syndrome is a disorder caused by defective genes. It is most commonly caused by parents who are elderly at the time of birth.
In Down syndrome, a person's cells have an extra copy of chromosome 21. In other words, instead of a pair of chromosomes, a person with down syndrome has three of that chromosome. Down syndrome most often occurs when chromosomes fail to separate properly during meiosis. People with down syndrome have a degree of mental retardation. Heart defects are also common, but can be treated.
Down Syndrome is spread fairly evenly between males and females. There does seem to be a slightly higher incidence among males, however.
The most common chromosomal abnormality in humans is Down syndrome, which is caused by an extra copy of chromosome 21. It occurs in about 1 in 700 births.
In Down syndrome, a person's cells have an extra copy of chromosome 21. In other words, instead of a pair of chromosomes, a person with Down syndrome has three of that chromosome. Down syndrome most often occurs when chromosomes fail to separate properly during meiosis. People with Down syndrome have a degree of mental retardation. Heart defects are also common, but can be treated.
The most common entrapment syndrome is carpal tunnel syndrome . Cubital tunnel syndrome of the ulnar nerve, which runs down the arm and through the elbow, also occurs frequently.