What causes chromosomal translocations?

Translocations generally result from swapping of chromosomal arms between heterologous chromosomes and hence are reciprocal in nature (Figure 1) (8,9). DNA double-strand breaks (DSBs) are prerequisites for such translocations, although little is known about their generation.

How are translocations formed?

Translocations occur when chromosomes become broken during meiosis and the resulting fragment becomes joined to another chromosome. Reciprocal translocations: In a balanced reciprocal translocation (Fig. 2.3), genetic material is exchanged between two chromosomes with no apparent loss.

How common is chromosomal translocation?

The most common translocation in humans involves chromosomes 13 and 14 and is seen in about 0.97 / 1000 newborns. Carriers of Robertsonian translocations are not associated with any phenotypic abnormalities, but there is a risk of unbalanced gametes that lead to miscarriages or abnormal offspring.

Are chromosomal translocations inherited?

A translocation is either inherited from a parent or happens around the time of conception. A translocation cannot be corrected – it is present for life. A translocation is not something that can be “caught” from other people. Therefore a translocation carrier can still be a blood donor, for example.

What causes BCR ABL translocation?

The BCR-ABL mutation happens when pieces of BCR and ABL genes break off and switch places. The piece of chromosome 9 that breaks off includes part of the ABL gene. When this piece moves over to chromosome 22, part of the ABL gene attaches to the BCR gene.

Understanding Chromosomal Translocation - Robertsonian Translocation v1.2

When does chromosomal translocation occur?

Deletions, duplications, and inversions can occur when joining involves two broken ends on the same chromosome. Furthermore, translocations may occur when the broken ends of two nonhomologous chromosomes are joined together.

How is BCR-ABL formed?

A gene formed when pieces of chromosomes 9 and 22 break off and trade places. The ABL gene from chromosome 9 joins to the BCR gene on chromosome 22, to form the BCR-ABL fusion gene. The changed chromosome 22 with the fusion gene on it is called the Philadelphia chromosome.

Can you have a healthy baby with translocation?

Conclusions: Balanced translocation carriers suffer from poor pregnancy prognosis. Couples with homologous Robertsonian translocations have little chance to give birth to normal/balanced offsprings.

Can you conceive naturally with balanced translocation?

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 causes translocation Down syndrome?

Translocation Down syndrome is a type of Down syndrome that is caused when one chromosome breaks off and attaches to another chromosome. In this case, there are three 21 chromosomes but one of the 21 chromosomes is attached to another chromosome.

How do you detect chromosomal translocations?

There are multiple techniques to detect defining chromosomal translocations and other abnormalities, including conventional cytogenetic analysis, fluorescence in situ hybridization (FISH), spectral karyotyping (SKY), DNA microarray analysis, polymerase chain reaction (PCR) analysis, and immunohistochemical (IHC) ...

How do you know if you have translocation?

Your geneticist will offer to test other members of your family to find out whether your translocation is a new one or a family one. A small blood sample is needed for the test. Testing both your parents may be enough but if that is not possible, other family members may also be invited for testing.

Can IVF help with balanced translocation?

IVF-PGD is a treatment option often used for individuals with balanced translocations in an effort to improve the likelihood of achieving a healthy pregnancy 3, 4 while maintaining a genetic link to both parents.

Where does translocation occur?

Translocation occurs within a series of cells known as the phloem pathway, or phloem transport system, with phloem being the principal food-conducting tissue in vascular plants. Nutrients are translocated in the phloem as solutes in a solution called phloem sap.

What are the genetic consequences of translocation?

Translocations generate novel chromosomes, but are often linked to disorders like infertility and cancer.

How do translocations produce phenotypic effects?

How do translocations produce phenotypic effects? Like inversions, translocations can produce phenotypic effects if the translocation breakpoint disrupts a gene or if a gene near the breakpoint is altered in its expression because of relocation to a different chromosomal environment (a position effect).

Does balanced translocation cause infertility?

Balanced translocation carriers are burdened with fertility issues due to improper chromosome segregation in gametes, resulting in either implantation failure, miscarriage or birth of a child with chromosomal disorders.

How can you prevent chromosomal abnormalities during pregnancy?

Taking a daily prenatal vitamin that contains 400 micrograms of folic acid for three months before becoming pregnant. Eating a healthful diet that contains foods that have folic acid, such as breakfast cereals, grain products, leafy greens, oranges and orange juice, and peanuts. Reaching or maintaining a healthy weight.

Is there a cure for translocation Down syndrome?

There's no specific treatment for Down syndrome. But there is a wide range of physical and developmental therapies designed to help people with Down syndrome reach their full potential. The earlier you start them, the better. Each child will have different needs.

What causes chronic myeloid leukemia?

CML is caused by a genetic change (mutation) in the stem cells produced by the bone marrow. The mutation causes the stem cells to produce too many underdeveloped white blood cells. It also leads to a reduction in the number of other blood cells, such as red blood cells.

What type of chromosomal rearrangement would likely generate the BCR-ABL fusion gene?

Leukemias that are caused by a mutation called Philadelphia chromosome are CML and Philadelphia chromosome-positive ALL. The mutation is a translocation, identified as, t(9;22)(q34;q11). This abnormal chromosome contains a fusion gene, consisting of the ABL gene and the BCR gene, producing the BCR-ABL oncogene.

What is a high BCR-ABL?

If the BCR-ABL1 level rises, then it indicates disease progression or recurrence and it may also indicate that the person has become resistant to imatinib. Additional genetic testing is often performed to detect the development of BCR-ABL1 kinase domain mutations associated with imatinib resistance.

How do you know if you have Down syndrome translocation?

Without doing a blood test, it is not possible to tell the difference between people with translocation Down syndrome and people with other types of Down Syndrome. All people with Down syndrome have some learning problems. The specific location of extra genes generally does not help us predict how a child will develop.

How does unbalanced translocation occur?

An unbalanced translocation occurs when a fetus inherits a chromosome with extra or missing genetic material from a parent with a balanced translocation.

Is translocation a mutation?

Department of Animal Science - Basic Animal Genetics

Translocations are chromosome mutations in which chromosome segments, and the genes they contain, change positions. Translocations can occur within a chromosome (intrachromosomal) or between chromosomes (interchromosomal).