Robertsonian translocation

Robertsonian translocation is a specific type of chromosome abnormality that involves the fusion of two specific chromosomes, namely the acrocentric chromosomes. This type of translocation, named after the American insect geneticist William R. B. Robertson, who first described a similar phenomenon in insects in 1916, is a common cause of genetic disorders, including Down syndrome and Patau syndrome.

Overview

In a Robertsonian translocation, the long arms of two acrocentric chromosomes have fused to form a single chromosome. This results in a carrier individual having 45 chromosomes in their cells instead of the usual 46. Despite this, they typically do not show any symptoms because the short arms of the acrocentric chromosomes, which are lost during the translocation, contain little genetic material.

Causes

Robertsonian translocations occur spontaneously during the formation of sperm or egg cells or may be inherited from a parent who carries the translocation. The most common types involve chromosome pairs 13 and 14, 14 and 21, or 15 and 22.

Effects

While carriers of a Robertsonian translocation are typically healthy, they have an increased risk of having children with genetic disorders. This is because their children may inherit an unbalanced set of chromosomes.

Diagnosis

Robertsonian translocations can be diagnosed through karyotyping, a laboratory procedure that allows visualization of an individual's chromosomes. Prenatal diagnosis methods such as amniocentesis and chorionic villus sampling can also detect these translocations in a developing fetus.

Management

There is no cure for Robertsonian translocations. However, individuals or couples who carry these translocations can benefit from genetic counseling to understand their reproductive risks and options.

See also

• Chromosomal translocation
• Genetic recombination
• Genetic variation

• Robertsonian translocation
  Robertsonian translocation
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  Centromere Placement
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  Human karyotype with bands and sub-bands