What type of chromosomal mutation results in two particular chromosomes joined together?
What type of chromosomal mutation results in two particular chromosomes joined together?
There are two main types of translocations: reciprocal and Robertsonian. In a reciprocal translocation, two different chromosomes have exchanged segments with each other. In a Robertsonian translocation, an entire chromosome attaches to another at the centromere.
What causes Robertsonian translocation?
A Robertsonian translocation results when the long arms of two acrocentric chromosomes fuse at the centromere and the two short arms are lost. If, for example, the long arms of chromosomes 13 and 14 fuse, no significant genetic material is lost—and the person is completely normal in spite of the translocation.
What is a balanced chromosomal rearrangement?
A balanced chromosomal rearrangement (or balanced chromosomal abnormality, BCA) is a type of chromosomal structural variant (SV) involving chromosomal rearrangements (e.g., translocations, inversions, and insertions) without cytogenetically apparent gain or loss of chromatin.
How common is translocation Down syndrome?
About 3 – 4% of people with Down Syndrome have translocation Down syndrome.
What are the symptoms of translocation Down syndrome?
In translocation Down syndrome, the extra 21 chromosome may be attached to the 14 chromosome, or to other chromosome numbers like 13, 15, or 22….Parents with balanced translocations may:
- Have trouble getting pregnant.
- Suffer miscarriages.
- Have an increased chance of having a child with health problems.
What causes the extra copy of chromosome 21?
About 95 percent of the time, Down syndrome is caused by trisomy 21 — the person has three copies of chromosome 21, instead of the usual two copies, in all cells. This is caused by abnormal cell division during the development of the sperm cell or the egg cell. Mosaic Down syndrome.
What is the politically correct term for Down syndrome?
For us at the Down’s Syndrome Association, the most important thing is the use of person first terminology (e.g. “person who has Down’s syndrome“, not “Down’s syndrome person“)….About Down’s Syndrome : Terminology Guide.
| Don’t Say | Do Say |
|---|---|
| retarded/mentally handicapped/backward/mental disability | learning disability |
What is the life expectancy of a Down syndrome?
What is the life expectancy for people with Down syndrome? The life expectancy of people with Down syndrome increased dramatically between 1960 and 2007. In 1960, on average, persons with Down syndrome lived to be about 10 years old. In 2007, on average, persons with Down syndrome lived to be about 47 years old.
What is the average lifespan of a person?
72.6 years