What is the most common Robertsonian translocation?
The most common Robertsonian translocation is between chromosomes 13 and 14. This D/D translocation makes up ~75% of all Robertsonians (Gardner and Sutherland, 1996).
What is Robertsonian translocation give example?
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.
Are Robertsonian translocations Dicentric?
Karyotypes from independent amniocenteses reflected a rare, unstable, functionally dicentric Robertsonian translocation chromosome in most cells in male Twin B who grew more slowly than the chromosomally normal female sib (Twin A).
Why do Robertsonian translocations occur?
Robertsonian translocation is a genetic abnormality. It occurs when two acrocentric chromosomes fuse. Most people with Robertson translocation do not know they have it. They live normal, healthy lives, though they may have concerns when starting a family.
Is Robertsonian translocation unbalanced?
The Robertsonian translocation is unbalanced and the baby has three copies of the long arm of chromosome 21 instead of two. This causes a type of Down’s syndrome called translocation Down’s syndrome. The effects on the baby are exactly the same as when Down’s syndrome is caused by having an extra entire chromosome 21.
How do Robertsonian translocations occur?
Robertsonian translocations occur between two acrocentric chromosomes, which are chromosomes in which the centromere is close to one end of the chromosome, resulting in a small (p for petit) length of genetic material beyond the centromere.
Is Robertsonian translocation reciprocal?
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 is the life expectancy of Robertsonian translocation?
Robertsonian translocations occur in approximately one in every 1000 newborns. Although most Robertsonian translocation carriers are healthy and have a normal lifespan, they are at increased risk of spontaneous abortions and risk of producing unbalanced gametes and, therefore unbalanced offspring.
Can Robertsonian translocation cause Down’s syndrome?
About 3% of cases of Downs syndrome occur due to Robertsonian translocation, most commonly t (14; 21), other types of translocations are very rare cause of the syndrome.