This is sometimes called centric-fusion translocation. Chromosomes 13 and 14, 13 and 21, or 21 and 22 fusing are the most common forms of Robertsonian translocation. Robertsonian translocation does not always cause health problems, and many people will never know they have it. They will usually live as long and healthy a life as their peers, providing there are no other health complications.
That said, in some cases, when Robertsonian translocation results in people having extra genetic material in their bodies, the translocation can lead to genetic disorders. Around 1 in 16, babies are born with trisomy It is also called Patau syndrome. Trisomy 13 usually occurs when people have three, rather than two, copies of chromosome It can also happen when chromosome 13 fuses to another chromosome. Trisomy 13 can cause physical abnormalities, such as extra fingers or toes, an opening in the lip, or cleft lip, or an opening in the roof of the mouth, or cleft palate.
Most babies born with trisomy 13 die within the first days or weeks of life. Around 5, babies are born with Down syndrome in the United States each year. Down syndrome occurs in around 1 in newborns.
Most cases are caused by having three rather than two copies of chromosome Experts call this trisomy Sometimes, Down syndrome occurs when part of chromosome 21 fuses with another chromosome. The condition results in mild to moderate intellectual disability and a characteristic facial appearance. Some can also experience digestive abnormalities. Robertsonian translocation is a genetic disorder.
People inherit it from their parents with the mother or father passing it to a child in their genes. In most cases, Robertsonian translocation does not cause any health problems or require treatment. People who carry the abnormality, however, may pass it on to their children. Aspiring parents may wish to seek genetic counseling before starting a family.
The genetic counselor will be able to talk about specific risks and benefits to help the would-be parents make a decision. The remaining possibilities are a child with normal chromosomes, a child with the balanced translocation, and a child with Down syndrome due to the unbalanced form of the translocation causing trisomy This child has inherited the Robertsonian translocation chromosome as well as a normal chromosome 21 from the carrier parent, and a normal 14 and a normal 21 chromosome from the other parent.
A parent who is a carrier for a Robertsonian translocation involving chromosome 21 therefore has a high risk of having a child affected with Down syndrome, compared with the low recurrence in regular trisomy 21 Down syndrome which is due to an error in cell division, and has a recurrence risk of about 1 in Centric fusion Robertsonian translocation. Since chromosomes come in pairs, you can have a Robertsonian translocation that disrupts your DNA strand, but leaves you with all of the genetic information that you need for your cells to multiply correctly.
Multiple miscarriages , difficulty getting pregnant, and pregnancies in which the fetus develops a trisomy or other genetic abnormality could be a sign that you or your partner has this translocation. If you or your partner carry a Robertsonian translocation, you may be at a higher risk for infertility or miscarriage. And when people with this translocation carry a child to term, the child may be at a higher risk for chromosomal imbalance. If either you or your partner has this translocation, a risk assessment that analyzes the DNA you carry as well as genetic counseling may need to be considered for future pregnancies.
A monosomy is a genetic alteration in which one half of a chromosome pair is missing. Robertsonian translocations can result in pregnancies that carry monosomy 14 and monosomy Both are considered nonviable. A trisomy is a genetic alteration in which there is an extra copy of a chromosome in a DNA strand, throwing the chain off balance.
A Robertsonian translocation can result in trisomy 14 or trisomy Trisomy 21 is also known as Down syndrome. If your Robertsonian translocation fuses another chromosome with chromosome 21, you may be genetically more predisposed to have a baby with Down syndrome.
Patau syndrome is a rare genetic condition that can cause heart defects and brain and spinal cord abnormalities. If your Robertsonian translocation fuses chromosome 13 with another chromosome, you may be a carrier for Patau syndrome. Babies born with Patau syndrome rarely live more than one year. Other monosomies and trisomies that can occur with Robertsonian translocations are nonviable.
This is why having a Robertsonian translocation goes along with a higher risk of miscarriage. Typically, people born with a Robertsonian translocation are healthy and have average life expectancies.
But finding out you have this genetic abnormality, and the possibility of it affecting your pregnancy or your children, can be confusing and stressful. Viability outcomes for certain genetic conditions vary considerably. Factors such as maternal age and health history play into statistics about translocation carriers and their pregnancies. Trisomy 13 and trisomy 21 both result in genetic conditions that are viable, but can have serious effects.
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