robertsonian translocation

(redirected from Robertsonian)

translocation

 [trans″lo-ka´shun]
the attachment of a fragment of one chromosome to a nonhomologous chromosome.
Translocation of a portion of one chromosome to another chromosome. Redrawn from Damjanov, 2000.
reciprocal translocation the mutual exchange of fragments between two broken chromosomes, one part of one uniting with part of the other.
robertsonian translocation that in which the breaks occur at the centromeres and entire chromosome arms are exchanged, usually involving two acrocentric chromosomes.

ro·bert·so·ni·an trans·lo·ca·tion

translocation in which the centromeres of two acrocentric chromosomes appear to have fused, forming an abnormal chromosome consisting of the long arms of two different chromosomes with loss of the short arms. A carrier of a balanced robertsonian translocation has only 45 chromosomes but near normal chromosomal complement and a clinically normal phenotype; however, he or she is at risk of having a child with unbalanced chromosomal complement. A person with an unbalanced robertsonian translocation is trisomic for the long arm of the chromosome.
Synonym(s): centric fusion
[W.R.B. Robertson, U.S. geneticist.]

robertsonian translocation

[rob′ərtsō′nē·ən]
the exchange of entire chromosome arms, with the break occurring at the centromere, usually between two nonhomologous acrocentric chromosomes. It produces one large, metacentric chromosome and one extremely small chromosome. The latter carries little genetic material and may be lost through successive cell divisions, leading to a reduction in total chromosome number. Compare balanced translocation, reciprocal translocation.
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Robertsonian translocation

ro·bert·so·ni·an trans·lo·ca·tion

(rob'ĕrt-sō'nē-ăn tranz'lō-kā'shŭn)
Translocation in which the centromeres of two acrocentric chromosomes appear to have fused, forming an abnormal chromosome consisting of the long arms of two different chromosomes; if the translocation is balanced, the individual is clinically normal but a carrier of the translocation; if the translocation is unbalanced, the individual is trisomic for the long arm of a chromosome.
Synonym(s): centric fusion.
[W.R.B. Robertson, U.S. geneticist.]

Robertson,

W.R.B., U.S. geneticist, 1881–.
robertsonian translocation - translocation in which the centromeres of two acrocentric chromosomes appear to have fused, forming an abnormal chromosome. Synonym(s): centric fusion

Robertsonian translocation

see Robertsonian translocation.
References in periodicals archive ?
Molecular studies demonstrated that the ring included a duplicated region with a concomitant distal deletion suggesting the following mechanism: an initial Robertsonian translocation occurred between one paternal and one maternal chromosome in a trisomic cell, followed by distal breakage and deletion in both long arms of the translocation, leading to the formation of a ring chromosome.
Carriers of structural chromosomal rearrangements such as Robertsonian or reciprocal translocations have an increased risk of spontaneous abortion and having children with congenital anomalies.
The analysis of chromosomal aberrations was classified as numeric (autosomal trisomy -21, 18, 13, 17, 7-, monosomy, triploidy, and sex CA), structural (inversion, deletion, de novo marker, Robertsonian translocation, reciprocal translocation, chromosomal variant), and single gene disorders (fragile X syndrome, maple syrup disease, spinal muscular atrophy, congenital adrenal hyperplasia, thalassemia).
Savic & Soldatovic (1979b) assumed that the evolution of karyotypes of the Balkan Spalacinae was driven by Robertsonian re-arrangements and most probably took the form of a decrease in the number of acrocentric autosomes and consequently of the diploid number of chromosomes.
Meanwhile, one or several chromosomal abnormalities, especially autosomal aberrations (including Robertsonian and balanced translocations) and pericentric and paracentric inversions, have been documented in about 8% of men with severe oligozoospermia (7).
These authors stated that the extant 2n = 70 FN = 84 karyomorphs found in Argentina and Uruguay are relicts of a more widespread distribution, from which lower chromosomal numbers could have originated by means of Robertsonian rearrangements.
Modifications in the diploid numbers and in the karyotypic formulas indicate that distinct rearrangements took place in the chromosome evolution of these fishes, such as Robertsonian rearrangements and that ones modifying the centromere position.
An example of the Robertsonian method can be seen in John V.
a) Normal metaphase, (b) chromatid-type gap, (c) isochromatid gaps, (d) chromosome fragments, (e) chromosome with dicentrics and the accompanying fragments, (f) Robertsonian translocation, (g) chromosome deletion, and (h) chromosomes with exchanged fragments.
A series of experiments using mice with Robertsonian translocations also provided strong genetic evidence for the functional differences between the paternally and maternally derived chromosomes, because mice with uniparental duplication of certain specific chromosomal regions exhibited a variety of defects in development, growth and/or behavior (Fig.
Birth after intracytoplasmic injection of epididymal sperm from a man with congenital bilateral absence of the vas deferens who had a robertsonian translocation.
After cell-free DNA analysis became clinically available in 2011, ACOG and SMFM recommended it for women at increased risk of fetal aneuploidy, including women 35 years or older, fetuses with ultrasonographic findings indicative of an increased risk of aneuploidy, women with a history of trisomy-affected offspring, a parent carrying a balanced robertsonian translocation with an increased risk of trisomy 13 or trisomy 21, and women with positive first-trimester or second-trimester screening test results.