Trisomy 1q

Diagnosis and Testing

How do I get tested for trisomy 1q?

In order to diagnose trisomy 1q (aka 1q duplication) the DNA will have to be evaluated. It cannot be diagnosed clinically - just by looking at the child. There are two tests that would be most commonly used to look at the DNA a karyotype or a microarray. Often times, it uses a blood draw. However, testing a pregnancy can be completed through amniocentesis or Chorionic villus sampling. Sometimes a punch biopsy to get a sample of the infant/child's skin is also used.

A karyotype is a picture of the chromosomes, which are instructions for the body. It allows your healthcare team to see if there are large amounts of duplication or deleted information. It can also see if large amounts of DNA are in the wrong place (translocation). A karyotype is helpful to diagnose full trisomy 1q - when the amount of duplicated DNA is large. To see an example of a karyotype and learn more about them, click here. However, if smaller amounts of DNA are duplicated or deleted in our DNA a karyotype is unable to see it - for these you need a test called a microarray.

A microarray is able to look closer at our DNA compared to the karyotype's "bird's eye view." The microarray is able to see "breakpoints" - where the duplicated DNA starts or stops. This can be important to determine what genes (sections of DNA that contain instructions for our body to develop and function) are affected to better predict how the individual may be affected.

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More Diagnosis and Testing Content

Is there newborn testing for trisomy 1q?

Is there more than one test to diagnose trisomy 1q?

Does it matter if you test blood vs. saliva vs biopsy to diagnose trisomy 1q?

Who else in my family should I test for trisomy 1q?

What does it mean to have a "variant" in the gene for trisomy 1q?

Is there newborn testing for trisomy 1q?

Trisomy 1q (aka 1q duplication) is not included in the newborn screen that is given to all new babies. However, if a newborn has birth defects or is not growing well, a doctor will likely order some tests to find out why. In order to diagnose trisomy 1q (aka 1q duplication) the DNA will have to be evaluated. It cannot be diagnosed clinically - just by looking at the child. There are two tests that would be most commonly used to look at the DNA a karyotype or a microarray. Often times, it uses a blood draw. Sometimes a punch biopsy to get a sample of the infant/child's skin is also used.

A karyotype is a picture of the chromosomes, which are instructions for the body. It allows your healthcare team to see if there are large amounts of duplication or deleted information. It can also see if large amounts of DNA are in the wrong place (translocation). A karyotype is helpful to diagnose full trisomy 1q - when the amount of duplicated DNA is large. To see an example of a karyotype and learn more about them, click here. However, if smaller amounts of DNA are duplicated or deleted in our DNA a karyotype is unable to see it - for these you need a test called a microarray.

A microarray is able to look closer at our DNA compared to the karyotype's "bird's eye view." The microarray is able to see "breakpoints" - where the duplicated DNA starts or stops. This can be important to determine what genes (sections of DNA that contain instructions for our body to develop and function) are affected to better predict how the individual may be affected.

References
Is there more than one test to diagnose trisomy 1q?

In order to diagnose trisomy 1q (aka 1q duplication) the DNA will have to be evaluated. It cannot be diagnosed clinically - just by looking at the child. There are two tests that would be most commonly used to look at the DNA a karyotype or a microarray. Often times, it uses a blood draw. However, testing a pregnancy can be completed through amniocentesis or Chorionic villus sampling. Sometimes a punch biopsy to get a sample of the infant/child's skin is also used.

A karyotype is a picture of the chromosomes, which are instructions for the body. It allows your healthcare team to see if there are large amounts of duplication or deleted information. It can also see if large amounts of DNA are in the wrong place (translocation). A karyotype is helpful to diagnose full trisomy 1q - when the amount of duplicated DNA is large. To see an example of a karyotype and learn more about them, click here. However, if smaller amounts of DNA are duplicated or deleted in our DNA a karyotype is unable to see it - for these you need a test called a microarray.

A microarray is able to look closer at our DNA compared to the karyotype's "bird's eye view." The microarray is able to see "breakpoints" - where the duplicated DNA starts or stops. This can be important to determine what genes (sections of DNA that contain instructions for our body to develop and function) are affected to better predict how the individual may be affected.

Does it matter if you test blood vs. saliva vs biopsy to diagnose trisomy 1q?

Most of the time, it doesn't matter if genetic testing is done on a blood sample, saliva, or a skin biopsy. However, some people can have different genetic information in different cell lines. This means the results may be different depending where the sample was taken from. These individuals are called mosaic. Mosaicism happens when a genetic change occurs very early in the development of the embryo so that some cell lines carry the genetic variation and others do not. If a doctor is very suspicious for a genetic problem and the blood test is normal then they may test a second tissue type, like a skin biopsy.

References
Who else in my family should I test for trisomy 1q?

Trisomy 1q (aka 1q duplication) is usually new to the person who has it, meaning that neither parent has trisomy 1q. If this is the case, it is most likely not necessary to test other family members. However, if it is determined the cause of the trisomy 1q is due to an unbalanced translocation, then it's often best to determine which parent carries the balanced translocation. That way family members on the right side of the family can be informed. For more information on balanced and unbalanced translocations visit this page from the Genetic Alliance.

Check with your healthcare team if you have additional questions about who in your family should be tested.

References
What does it mean to have a "variant" in the gene for trisomy 1q?

Usually, the word "variant" in regards to genetics is reserved for a change within a gene. Genes are smaller parts of the larger chromosome and contain instructions for our body's growth and development. With trisomy 1q (aka 1q duplication), there are not variants in the gene. Instead genes are duplicated because parts of the chromosome has been duplicated. The extra (3rd) copy of the genes is what causes the problems associated with trisomy 1q.

References

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