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.
Down Syndrome is spread fairly evenly between males and females. There does seem to be a slightly higher incidence among males, however.
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.
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 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.
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.