Robertsonian Translocations: Causes, Risks & Diagnostic Testing

Robertsonian translocation

Translocation in which the long arms of two acrocentric chromosomes become joined to a common centromere, resulting in a chromosome with two long arms and usually another chromosome with two short arms.

A Robertsonian translocation is a type of structural chromosomal rearrangement that occurs when two acrocentric chromosomes (chromosomes with a very short p-arm that lacks essential genes) fuse near their centromeres, resulting in the loss of two small p-arms and the formation of a single large metacentric chromosome containing both long q-arms. This type of translocation usually involves chromosomes 13, 14, 15, 21, 22, and rarely, 2 and 3.

Robertsonian translocations do not usually cause any physical or developmental abnormalities because no genetic material is lost or duplicated; however, they can result in the production of imbalanced gametes during meiosis. This can lead to either a loss or gain of genetic material in the offspring, which can cause genetic disorders such as Down syndrome when the translocation involves chromosome 21. In some cases, those with Robertsonian translocations may experience repeated miscarriages or infertility due to problems with gamete production or implantation.

Robertsonian translocations are typically diagnosed through karyotype analysis, which involves the visualization of chromosomes under a microscope. Testing for translocations is sometimes recommended for couples with a history of recurrent miscarriages or genetic disorders. If a Robertsonian translocation is detected, genetic counseling is often recommended to discuss the risks and options available for family planning. In some cases, prenatal testing may be recommended for couples carrying a Robertsonian translocation to assess for possible fetal abnormalities.

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