All about Robertsonian Translocation

Robertsonian translocation is a kind of chromosomal rearrangement that occurs within five acrocentric human chromosome pairs, namely 13, 14, 15, 21 and 22. They are named after the American geneticist insects WRB Robertson, who first described a Robertsonian translocation in grasshoppers in 1916. They are also called the whole arm or transfers focused on the merger-transfer. They are a type of chromosomal translocation. A Robertsonian translocation is a type of transfer nonreciprocal in which two nonhomologous acrocentric chromosomes break at their centromeres, following which the long arms focus on a single centromere. The short arms also join to form a product of reciprocity, which generally contains genes and nonessential is usually lost within a few cell divisions.

In humans, when a Robertsonian translocation joined the long arm of chromosome 21 with the long arm of chromosome 14 (or 15), the carrier is heterozygous phenotypically normal because there are two copies of all major chromosome arms and hence two copies of all genes essential. However, the descendants of that carrier May inherit an imbalance of trisomy 21, which causes Down’s syndrome. About one thousand newborns has a Robertsonian translocation. The most often forms of Robertsonian translocation between chromosomes 13 and 14, 13 and 21 and 21 and 22 and occurs when the long arms of two acrocentric chromosomes fuse with the centromere and two short arms are lost. A Robertsonian translocation balanced form results in any surplus or deficit of genetic material and does not cause health problems. In asymmetrical forms, Robertsonian translocations cause chromosomal deletions or more and give rise to multiple malformations syndromes, including trisomy 13 and trisomy 21.

A Robertsonian translocation results when the long arms of two acrocentric chromosomes fuse with the centromere and two short arms are lost. In this case, the long arm of chromosomes 13 and 14 have merged, but not the genetic material has been lost – this person is quite normal despite the transfer. Commune Robertsonian translocations are confined to the acrocentric chromosomes 13, 14, 15, 21 and 22, because the short arms of these chromosomes to encode rRNA, which is present in multiple copies. People with Robertsonian translocations have only 45 chromosomes in each of their cells, but the bulk of genetic material is present, and they seem normal. Their children, however, May is normal or fusion of chromosomes, or May, they inherit a missing or extra long arm of chromosome one acrocentric. Genetic counseling and genetic testing is offered to families that May be carriers of chromosomal translocations.


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