Robertsonian translocation is a genetic condition that occurs when chromosomes break and rejoin, resulting in a rearrangement of genetic material. The spelling of "Robertsonian" is pronounced as /ˌrɒbətsəʊˈniːən/ in IPA phonetic transcription. In this word, the "R" is pronounced as an unvoiced alveolar trill, and the "t" is pronounced as an unvoiced alveolar stop. The second syllable, "-sonian," is pronounced with a schwa sound followed by a long "e" sound. Understanding the correct pronunciation of this word is crucial for proper communication among medical professionals when discussing this genetic condition.
Robertsonian translocation is a type of chromosomal abnormality that occurs when two non-homologous chromosomes merge and exchange genetic material. It is named after the American geneticist Dr. William R. Robertson, who first described this phenomenon in 1940. This translocation involves the fusion of two acrocentric chromosomes, which are a type of chromosome with a very short arm compared to the long arm. In a Robertsonian translocation, the short arms of two acrocentric chromosomes break and the long arms fuse together to form a single chromosome.
The resulting chromosome contains the genetic material from both parent chromosomes, but it is balanced because it does not involve any gain or loss of genetic material. This means that the person carrying the Robertsonian translocation does not usually manifest any physical or developmental abnormalities. However, this rearrangement can have significant implications for reproduction.
Robertsonian translocations can cause fertility issues or recurrent pregnancy loss in affected individuals. This occurs when the translocated chromosomes pair up improperly during meiosis, leading to the production of unbalanced gametes. When these unbalanced gametes participate in fertilization, it can result in embryos with extra or missing genetic material, causing miscarriages or live births with congenital abnormalities.
Robertsonian translocations are diagnosed through cytogenetic analysis, typically using techniques such as karyotyping or fluorescence in situ hybridization (FISH). Genetic counseling is often recommended for individuals with Robertsonian translocations to discuss the implications of the rearrangement for their fertility and to provide information about prenatal testing options for couples planning to have children.
The term "Robertsonian translocation" is derived from the name of the scientist who first described this type of chromosomal rearrangement, Dr. William Robertsons.
To provide a brief background, Dr. William Robert Robertson was a British geneticist and cytologist who made significant contributions in the field of human genetics. In 1956, he published a seminal paper detailing a specific type of chromosomal rearrangement that came to be known as a "Robertsonian translocation".
Robertsonian translocation refers to the fusion of two acrocentric chromosomes (chromosomes with the centromere near one end) with subsequent loss of their short arms. This results in a single larger chromosome with a single centromere, effectively reducing the total chromosome count by one. Such translocations can occur between any pair of acrocentric chromosomes.