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Down syndrome is usually caused by a condition known as Trisomy 21, which means that a person has three copies of Chromosome 21, rather than the usual two copies. An extra chromosome is added. The normal amount is 46, but people with Down syndrome have 47.
Occasionally, the condition is a result of part of Chromosome 21 becoming fused to the end of another chromosome.
More info on Chromosome 21
While Chromosome 21 isn't the shortest chromosome, it is the one that contains the fewest genes (other than the Y chromosome). This is because genes on Chromosome 22 are more closely spaced, and thus the chromosome contains more genes, despite its smaller size.
Wiki User
∙ 8y ago
Wiki User
∙ 9y agoA baby will have an extra 21st chromosome on each strain of their DNA. This means on each DNA set there are three of 21 instead of two, which is why Down Syndrome is also referred to as Trisonomy 21.
Wiki User
∙ 14y agoYou have the terms reversed. Chromosomes, or the genes within them, cause Downs Syndrome
Wiki User
∙ 11y agoNo, Down Syndrome is caused by having an extra copy (three in total) of chromosome 21. This is why Down Syndrome is also known as Trisomy 21.
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What is the diagnosis if you have 92 chromosomes?
down's syndrome
What effect does trisomy-21 have?
By having three chromosomes of the 21 type more protein product is made and the Down's syndrome is expressed.
What is the number of chromosomes affected in down syndrome?
#21
Why is it that a mongoloid person have 65 chromosomes?
People with Down syndrome, also called mongoloidism have 47 chromosomes. Having 65 chromosomes would be lethal, as normally having 47 chromosomes is lethal. Down syndrome is also known as trisomy 21, because instead of two copies of chromosome 21, a person with Down syndrome has three copies, which accounts for the 47th chromosome.
What is an example of a disorder associated with an error in the number of chromosomes present?
Down syndrome (trisomy 21) is a disorder associated with an error in the number of chromosomes present. Other examples of disorders associated with an error in the number of chromosomes are Trisomy 18 (Edwards Syndrome), Trisomy 13 (Patau Syndrome), Triple X syndrome, and Klinefelter Syndrome.
What is the genetic disorder for having three 21 chromosomes?
down syndrome
What is the total amount of chromosomes do down syndrome children have?
21 chromosomes
What chromosomes do you get an extra copy for in humans that results in Down syndrome?
Down Syndrome is caused by a triplication of the 21st chromosome.
What is the diagnosis if you have 92 chromosomes?
down's syndrome
People with down syndrome have how many chromosomes?
47There are 47 chromosomes in someone with Down syndrome; the 21st pair has an extra chromosome. Most people have 46 chromosomes. Down syndrome is also known as "Trisomy 21" - a reference to the fact that someone with Down syndrome has 3 pairs of chromosomes on their 21st pair.
What effect does trisomy-21 have?
By having three chromosomes of the 21 type more protein product is made and the Down's syndrome is expressed.
What happens if a person have more chromosomes?
If it had more chromosomes it will cause to down's syndrome
Down Syndrome most often occurs when-?
Down Syndrome often occurs when chromosomes fail to separate properly during meiosis.
How do you spell downsindrowm?
The phrase is spelled Down Syndrome. Down Syndrome is a disorder caused by a mutation of the chromosomes.
What is the number of chromosomes affected in down syndrome?
#21
Difference between the chromosomes of a person with Down syndrome and a person without Down syndrome?
An individual with Down Syndrome has the presence of all or part of an extra 21st chromosome.
Would a kartotype would be most likely be used to diagnose Down syndrome?
A person with Down Syndrome will have 3 chromosomes for the 21st autosome. Karyotypes show these chromosomes which help to diagnose Down Syndrome.
