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Topic: Robertsonian translocation


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In the News (Wed 26 Jun 19)

  
  Robertsonian translocation - Biocrawler
Robertsonian translocations are a common form of chromosomal rearrangement, which occurs in the five acrocentric human chromosome pairs, namely 13, 14, 15, 21, and 22.
One in 900 humans is born with a Robertsonian translocation.
The most frequent forms of Robertsonian translocations are between chromosomes 13 and 14, 13 and 21, and 21 and 22, and occur when the long arms of two acrocentric chromosomes fuse at the centromere and the two short arms are lost.
www.biocrawler.com /encyclopedia/Robertsonian_translocation   (0 words)

  
 Robertsonian translocation
Robertsonian translocations are a common form of chromosomal rearrangement that occurs in the five acrocentric human chromosome pairs, namely 13, 14, 15, 21, and 22.
A Robertsonian translocation is a type of nonreciprocal translocation in which two nonhomologous acrocentric chromosomes (chromosomes with centromeres near their ends) break at their centromeres, following which the long arms become attached to a single centromere.
In humans, when a Robertsonian translocation joins the long arm of chromosome 21 with the long arm of chromosome 14 (or 15), the heterozygous carrier is phenotypically normal because there are two copies of all major chromosome arms and hence two copies of all essentail genes.
www.bssintranet.com /encyclopedia/Genetics/Robertsonian_translocation.php   (0 words)

  
 Translocation, Robertsonian definition - Medical Dictionary definitions of popular medical terms
Translocation, Robertsonian: A relatively very common and medically significant type of chromosome rearrangement that is formed by fusion of the whole long arms of two acrocentric chromosomes (chromosomes with the centromere near the very end).
Robertsonian translocations between chromosomes 13 and 14 lead to the trisomy 13 (Patau) syndrome.
Robertsonian translocations are named for the America insect geneticist W.R.B. Robertson who first described this form of translocation (in grasshoppers) in 1916 and are also known as whole-arm or centric-fusion translocations or rearrangements.
www.medterms.com /script/main/art.asp?articlekey=15920   (0 words)

  
  NationMaster - Encyclopedia: Chromosomal translocation   (Site not responding. Last check: 2007-10-29)
In genetics, a chromosome translocation is an abnormal chromosomal rearrangement caused by the interchange of parts between nonhomologous chromosomes.
Also, translocations can be balanced (in an even exchange of material with no genetic information extra or missing) or unbalanced (where the exchange of chromosome material is unequal resulting in extra or missing genes).
Down syndrome is caused in a minority (5% or less) of cases by a Robertsonian translocation of about a third of chromosome 21 onto chromosome 14.
www.nationmaster.com /encyclopedia/Chromosomal-translocation   (1660 words)

  
 Internet Resources for School Reports on Down Syndrome
"Translocation" refers to one type of rearrangement of chromosomal material; in DS almost all translocations are Robertsonian translocations, named for Dr. Roberts, an Australian chromosome expert who originally described this type of translocation.
In about three-fourths of translocation DS neither parent is a carrier, and a mutation in the germ cells of one parent has caused the translocation.
In cases of a new, or de novo, Robertsonian translocation, the risk of a couple producing a second DS is low, estimated to 2-3 %.
www.ds-health.com /benke.htm   (0 words)

  
 A 22;22 Robertsonian Translocation in a Patient with Repeated Abortions
Robertsonian translocation is one of the major chromosomal re-arrangements and comprises 18% of total genetic abnormalities.
On the basis of GTG-banding and karyotyping, it was found that a Robertsonian translocation in the chromosome 22;22 was the primary cause of this syndrome.
Robertsonian translocations may be present in different family members but its penetrance in population is low.
www.ams.ac.ir /AIM/0033/kiani0033.html   (0 words)

  
 Robertsonian translocation - Psychology Wiki - a Wikia wiki
Robertsonian translocation is a common form of chromosomal rearrangement that occurs in the five acrocentric human chromosome pairs, namely 13, 14, 15, 21, and 22.
A Robertsonian translocation is a type of nonreciprocal translocation in which two nonhomologous acrocentric chromosomes (chromosomes with centromeres near their ends) break at their centromeres, following which the long arms become attached to a single centromere.
The most frequent forms of Robertsonian translocations are between chromosomes 13 and 14, 13 and 21, and 21 and 22, and occur when the long arms of two acrocentric chromosomes fuse at the centromere and the two short arms are lost.
psychology.wikia.com /wiki/Robertsonian_translocation   (646 words)

  
 Robertsonian translocation at AllExperts
Robertsonian translocation is a common form of chromosomal rearrangement that occurs in the five acrocentric human chromosome pairs, namely 13, 14, 15, 21, and 22.
A Robertsonian translocation is a type of nonreciprocal translocation in which two nonhomologous acrocentric chromosomes (chromosomes with centromeres near their ends) break at their centromeres, following which the long arms become attached to a single centromere.
Common Robertsonian translocations are confined to the acrocentric chromosomes 13, 14, 15, 21 and 22, because the short arms of these chromosomes encode for rRNA which is present in multiple copies.
en.allexperts.com /e/r/ro/robertsonian_translocation.htm   (549 words)

  
 © The Centre for Genetics Education   (Site not responding. Last check: 2007-10-29)
Translocation of these chromosomes involves loss of the short arms and fusion of two chromosomes at the centromere, resulting in one chromosome which consists of two long arms of either the same numbered chromosome or two different chromosomes and containing either one or both centromeres.
Robertsonian translocations between the same chromosome pair are very rare and almost always occur as a spontaneous or one-off event, with no other person in the family having a similar chromosomal arrangement.
Some translocations that are carried by a parent have up to 20% risk or more of causing a genetic condition in their child, some a risk in the 5-10% range, while others have a relatively low risk of 1% or less of causing a problem.
www.genetics.com.au /factsheet/13.htm   (1930 words)

  
 Definition of Translocation   (Site not responding. Last check: 2007-10-29)
In genetics, a chromosome translocation is the interchange of parts between nonhomologous chromosomes.
Like other translocations, carriers of Robertsonian translocations are phenyotypically normal, but there is a risk of unbalanced gametes and therefore miscarriages or abnormal offspring.
For exmple, carriers of robertsonian translocations involving chromosome 21 have a higher chance to have a child with Down syndrome.
www.wordiq.com /definition/Translocation   (388 words)

  
 ABNORMALITIES IN CHROMOSOME STRUCTURE
Individuals and families have been described with a translocation chromosome abnormality and a concurrent genetic condition; the genetic condition occurring because the chromosome breakpoint is in the midst of a gene.
A Robertsonian translocation is a particular type of translocation involving the reciprocal transfer of the long arms of two of the acrocentric chromosomes: 13, 14, 15, 21 or 22.
A relatively common Robertsonian translocation is between chromosome 14 and chromosome 21.
www.usd.edu /med/som/genetics/curriculum/1ECHROM3.htm   (1824 words)

  
 Cecil Textbook of Medicine : />
Translocations involve the transfer of chromosomal material from one chromosome to another and occur because of a break in the chromosomes.
Robertsonian translocation involves acrocentric chromosomes (i.e., chromosomes in which the centromere is located near the end of the chromosome).
Robertsonian translocations comprise the fusion of the two long arms of two such chromosomes, and the individual carrying a robertsonian translocation only has 45 chromosomes.
www.merckmedicus.com /ppdocs/us/common/cecils/chapters/038_015.htm   (866 words)

  
 Eastern Mediterranean Health Journal
Translocation was parentally inherited for 33.3% of cases and maternal transmission was twice as common as paternal.
In familial Robertsonian translocation Down syndrome one of the parents (almost always the mother) is a translocation heterozygote and has transmitted the translocation in an unbalanced state to the offspring.
In the case of familial Robertsonian translocation Down syndrome, the genetic risk for the female carrier to have a liveborn child with translocation Down syndrome is about 10%, while the likelihood to detect translocation trisomy 21 at amniocentesis is about 15%.
www.emro.who.int /Publications/EMHJ/0901_2/cytogenetic.htm   (2659 words)

  
 Breakpoint diversity illustrates distinct mechanisms for Robertsonian translocation formation -- Page et al. 5 (9): ...
The most common translocations in humans are whole arm exchanges between acrocentric chromosomes, termed Robertsonian translocations, which have an incidence of approximately 1/1000 individuals (1).
The high overall frequency of Robertsonian translocation formation is thought to be influenced by the presence of nucleolar organizer regions (NOR), which contain ribosomal RNA genes (rDNA) at band p12 of each acrocentric chromosome (22 -25).
The homologous sequences involved in translocation formation would have to be in opposite orientation on chromosome 14 as to facilitate recombination resulting in rob(13q14q) and rob(14q21q), but not rob(13q21q) (refs 1,58,59).
hmg.oxfordjournals.org /cgi/content/full/5/9/1279   (6555 words)

  
 _13c
Robertsonian translocations are demonstrated as a mutual translocation between the long arms of D group 13–15 and G group 21–22 in chromosomes (1).
The formation process of congenital Robertsonian translocation may include the case in which this translocation is already observed in the gamate of parents or when it occurs in the process of cell division to fertilization in spite of the normal gamate of both parents.
However, considering that the chromosomal abnormality of Robertsonian translocation in the blood cells once disappeared, demonstrating normal karyotype at the time of hematological remission by induction therapy, the present case of Robertsonian translocation is suggested to be of acquired nature as was observed in the cases reported in the literature.
www.naika.or.jp /im2/43/06/13c.aspx   (1549 words)

  
 robertsonian translocation Information from Drugs.com
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.
www.drugs.com /dict/robertsonian_translocation.html   (0 words)

  
 Human Genetics - Chromosomal Inheritance 1
Robertsonian translocations are limited to the acrocentric chromosomes, chromosomes 13, 14, 15, 21, and 22.
Because Robertsonian translocation is responsible for about 9% of the Down syndrome children born to mothers under the age of 30, it is important to karyotype the child to determine if the child is the result of a Robertsonian translocation or simple meiotic nondisjunction.
Robertsonian translocations are passed from generation to generation, and with this type of inheritance Down syndrome may "run in families."
www.uic.edu /classes/bms/bms655/lesson9.html   (2625 words)

  
 Robertsonian Translocation
This karyotype is from a woman with 45 chromosomes and a balanced Robertsonian translocation of material between chromosome 13 and 14.
Although people with these translocations have only 45 chromosomes in each of their cells, all essential genetic material is present, and they appear normal.
Their children, however, may either be normal and carry the fusion chromosome, or they may inherit a missing or extra long arm of an acrocentric chromosome.
gslc.genetics.utah.edu /units/disorders/karyotype/robertsonian.cfm   (0 words)

  
 Spartanburg SC | GoUpstate.com | Spartanburg Herald-Journal
Robertsonian translocation is a common form of chromosomal rearrangement that occurs in the five acrocentric human chromosome pairs, namely 13, 14, 15, 21, and 22.
They are named after the American insect geneticist W. Robertson, who first described a Robertsonian translocation in grasshoppers in 1916
In humans, when a Robertsonian translocation joins the long arm of chromosome 21 with the long arm of chromosome 14 (or 15), the heterozygous carrier is phenotypically normal because there are two copies of all major chromosome arms and hence two copies of all essential genes.
www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=Robertsonian_translocation   (0 words)

  
 Pericentromeric organization at the fusion point of mouse Robertsonian translocation chromosomes -- Garagna et al. 98 ...
The Robertsonian (Rb) translocation is one of the most common chromosomal rearrangements in mammals (1, 2).
Pericentromeric regions involved in Rb translocations are composed of highly repetitive DNA families (satDNA).
to be the precise molecular substrate for Rb translocations in
www.pnas.org /cgi/content/full/98/1/171   (0 words)

  
 Trisomy 18 Support - Site Sections
This is the first form of a parent being able to "pass on" a trisomy to their child.
A Robertsonian Translocation is a little different, in that they only happen in chromosomes where the p arm is very short (13, 14, 15, 21 and 22).
Having a child with a trisomy (if that trisomy is not caused by a translocation or Robertsonian translocation) increases your potential risks by 1% - that is, 1% on top of the normal 2% - 3%.
www.trisomy18support.org /modules/wfsection/index.php?category=3   (1340 words)

  
 Trisomy 18 Foundation: Genetics   (Site not responding. Last check: 2007-10-29)
This is the first form of a parent being able to "pass on" a trisomy to their child.
A Robertsonian Translocation is a little different, in that they only happen in chromosomes where the p arm is very short (13, 14, 15, 21 and 22).
Having a child with a trisomy (if that trisomy is not caused by a translocation or Robertsonian translocation) increases your potential risks by 1% - that is, 1% on top of the normal 2% - 3%.
www.trisomy18.org /site/News2?page=NewsArticle&id=5313   (1303 words)

  
 Translocations - Children's Hospital of Philadelphia
Robertsonian translocation happens only between chromosomes 13, 14, 15, 21 and 22.
The translocation in this example is between chromosomes #14 and 21.
A person carrying this type of translocation is healthy, but would have an increased risk of having a baby with Down syndrome.
www.chop.edu /consumer/your_child/wellness_index.jsp?id=-8549   (154 words)

  
 Origin of the deviating chromosome structure
With reciprocal translocations gamete formation is connected with disorders because chromosomes in the region of the translocation cannot readily pair.
Today it is known that balanced translocations can also lead to pathogenic disorders in that proto-oncogenes, which as normal genes in their customary environment are frequently responsible for the controlling cell proliferation, can be transformed into oncogenes through translocation events (connections with other genes).
It is a special kind of translocation in that on the acrocentric chromosomes (most often chromosomes 14 and 21 or 22) the very short, satellite-bearing arm is lost and a centric fusion t(14q21q or 14q22q) of the two remainder chromosomes, i.e., the long arms of the two pieces, results.
www.embryology.ch /anglais/kchromaber/abweichende03.html   (621 words)

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