1, 2 Reciprocal translocation is the most common type of translocation; it can further be classified into balanced and unbalanced rearrangements.
What is the most problematic phenotype in reciprocal translocation?
Table 1
| Patient | Carrier karyotypea | Gene Ontology |
|---|---|---|
| 5 | 46,XY,t(8;20)(p21.3;q13.33) | – |
| 6 | 46,XY,t(6;22)(p12.1;q11.21) | – |
| – | ||
| 7 | 46,XX,t(4;9)(q21.23;q21.13) | NA |
What is unbalanced chromosome translocation?
An unbalanced translocation occurs when a fetus inherits a chromosome with extra or missing genetic material from a parent with a balanced translocation.
What are the three possibilities for segregation of a reciprocal translocation?
Reciprocal translocations can segregate in three ways: alternate, adjacent-1, and infrequently, adjacent-2.
Can I get pregnant with a balanced translocation?
BALANCED TRANSLOCATION AND RECURRENT MISCARRIAGE Natural conception and live birth is possible in cases of balanced translocation, but those with the condition may have more difficulty conceiving and are at a greater risk of recurrent miscarriage than those without it.
What is an example of reciprocal translocation?
A prototypical example of this phenomenon is represented by the Philadelphia chromosome associated with human lymphoma/leukemia. This specific chromosomal abnormality consists of a translocation between the long arms of chromosomes 9 and 22 and is seen in 85% of patients with chronic myelogenous leukemia.
What is a balanced reciprocal translocation?
A balanced reciprocal translocation consists of reciprocal material exchange between two non-homologous chromosomes. Usually, balanced reciprocal translocations can be diagnosed by karyotype analysis (an example of translocation name within a karyotype report could be: 46,XX,t(12:18)(p12;q12.
What causes reciprocal translocation?
Reciprocal translocations occur due to the exchange of chromosome material between two nonhomologous chromosomes. When the amount of genetic material is balanced, there is no phenotypic effect on the individual because of a balanced complement of genes.
What is non reciprocal translocation?
Nonreciprocal translocations are one-way translocations in which a chromosomal segment is transferred to a nonhomologous chromosome. Reciprocal translocations, on the other hand, involve the exchange of segments from two nonhomologous chromosomes.
What are unbalanced gametes?
unbalanced gamete. Definition. Genetically unbalanced gamete in F1 progeny caused by chromosome translocations whose exchange of chromosome material is unequal resulting in extra or missing genes; this is the main chromosomal mechanism of inherited sterility (IS) (J. Carpenter, personal communication).
Does balanced translocation cause birth defects?
This is because a person with a balanced translocation can make egg or sperm cells with too much of one chromosome and too little of the other. This can cause infertility, miscarriage or the birth of a child with intellectual disabilities and/or birth defects.
What is a carrier of balanced reciprocal translocation?
A carrier of a balanced reciprocal translocation can produce unbalanced gametes, resulting in zygotes with partial trisomy and partial monosomy for the defined chromosomal regions. A zygote with the pattern on the left has normal chromosomes.
How do chromosomes segregate at meiosis in a balanced reciprocal translocation?
How the chromosomes segregate at meiosis in a balanced reciprocal translocation carrier. A carrier of a balanced reciprocal translocation can produce unbalanced gametes, resulting in zygotes with partial trisomy and partial monosomy for the defined chromosomal regions.
What is the difference between G-banding and reciprocal translocations?
Often, there is loss of DNA at the break point that is too small to be detected by G-banding; this usually occurs in non-coding DNA and is inconsequential, but rarely may interrupt a gene and cause a phenotype. Reciprocal translocations are usually specific to a family but there are several which are known to occur more commonly.
What is the risk of an unbalanced translocation?
The risk of a live-born infant with an unbalanced translocation is specific to each reciprocal translocation and is difficult to calculate depending on which segments of chromosomes are involved, how large they are and whether there are reports of other live-born infants with the same karyotype. It is important to note this is not a 1 in 4 risk.
