What Does Pregnancy Genetic Testing Test For?

What Does Pregnancy Genetic Testing Test For
The cell-free DNA in a sample of a woman’s blood can be screened for Down syndrome, Patau syndrome (trisomy 13), Edwards syndrome, and problems with the number of sex chromosomes. This test can be done starting at 10 weeks of pregnancy. It takes about 1 week to get the results.
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What genetic testing is done during pregnancy?

Chorionic Villus Sampling (CVS)? – CVS is a prenatal test that involves taking a sample of some of the placental tissue. This tissue contains the same genetic material as the fetus and can be tested for chromosomal abnormalities and some other genetic problems. Testing is available for other genetic defects and disorders, depending on your family history and the availability of lab testing at the time of the procedure.
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What genetic testing is done at 12 weeks?

Typically, first trimester screening is done between weeks 11 and 14 of pregnancy. Using your age and the results of the blood test and the ultrasound, your health care provider can gauge your risk of carrying a baby with Down syndrome or trisomy 18.
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What happens if genetic testing is positive?

Positive result – A positive result means that testing has identified a gene change or genetic mutation in one or more of the genes analyzed. This type of result may be called a pathogenic or disease-causing variant. A positive result typically means that you’re at higher risk of developing a hereditary condition.
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Does genetic testing show all abnormalities?

What are the risks and limitations of genetic testing? The physical risks associated with most genetic tests are very small, particularly for those tests that require only a blood sample or buccal smear (a method that samples cells from the inside surface of the cheek).

  • The procedures used for prenatal diagnostic testing (called amniocentesis and chorionic villus sampling) carry a small but real risk of losing the pregnancy (miscarriage) because they require a sample of amniotic fluid or tissue from around the fetus.
  • Many of the risks associated with genetic testing involve the emotional, social, or financial consequences of the test results.

People may feel angry, depressed, anxious, or guilty about their results. In some cases, genetic testing creates tension within a family because the results can reveal information about other family members in addition to the person who is tested. The possibility of genetic discrimination in employment or insurance is also a concern.

  • Refer to for additional information.) Genetic testing can provide only limited information about an inherited condition.
  • The test often can’t determine if a person will show symptoms of a disorder, how severe the symptoms will be, or whether the disorder will progress over time.
  • Another major limitation is the lack of treatment strategies for many genetic disorders once they are diagnosed.

A can explain in detail the benefits, risks, and limitations of a particular test. It is important that any person who is considering genetic testing understand and weigh these factors before making a decision. : What are the risks and limitations of genetic testing?
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Can genetic testing tell gender?

The NIPT test is a noninvasive blood test that’s available to all pregnant women beginning at 10 weeks of pregnancy, It screens for Down syndrome and some other chromosomal conditions, and it can tell you whether you’re having a boy or a girl. NIPT is a screening test, so it’s not definitive. If NIPT indicates a possible problem, experts recommend having CVS or amniocentesis to be sure.
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How long does it take to get genetic testing results back?

Genetic Testing – How is the genetic test done? If you decide to have genetic testing, you will typically have a blood sample taken. The blood sample is sent to a specialized laboratory for analysis. Less often, other types of samples are used, such as saliva (spit) or a skin sample.

  • more frequent cancer screenings
  • screening tests specific to your cancer risk
  • surgery that can reduce your risk
  • certain medications

Can I eat before my blood test? Yes, you can eat as you normally would. How many genes will be on my test? What types of genetic testing are there? Genetic testing can include analysis of one gene or multiple genes. Often, more than one gene is linked to a certain type of cancer.

Depending on the cancers that have occurred in you and/or your family, you may be offered a test that looks at multiple genes. More recently, “multi-gene panels” are becoming a common choice. This testing allows for large groups of genes to be analyzed at the same time. The risks, benefits, and limitations of multi-gene panel testing will be discussed during your genetic counseling visit.

What is the difference between genetic testing done on a tumor versus a blood sample?

  • Genetic testing on a blood sample gives information about the genes that you were born with, known as the “germline.” Mutations that occur in the germline are hereditary and can be passed on to children.
  • Genetic testing on a tumor sample shows genetic changes that have occurred within the cells of a developing tumor. These are usually “acquired” genetic changes. Acquired genetic changes cannot be passed on to children.

How long will it take to get my genetic test results? The amount of time depends on the specific test that was ordered. Most tests are returned within 2-3 weeks, but some may take up to 8 weeks. Your genetic counselor will review this with you during your appointment.

How will I get my results? Learning genetic test results can bring up emotions for some people; therefore how you learn the results is up to you. Many patients prefer to learn their genetic test results over the phone, and will schedule a follow up visit to discuss the results in person if needed. Other patients will prefer to receive their results during a planned visit.

Your genetic counselor can help you to decide what is best for you. Is genetic testing covered by health insurance? Genetic testing is usually covered by insurance when indicated. Coverage usually depends on many factors, including your specific insurance plan and the cancer history in your family.

The genetic counselor will review this information with you during your initial genetic counseling appointment and may be able to work with your insurance company to obtain coverage for testing. For patients who are not covered for genetic testing by insurance, it is important to note that the cost of genetic testing is becoming more affordable for patients who have to pay for this out of pocket.

Is my genetic information protected? Yes. Your genetic test results are protected under the same HIPAA laws as the rest of your medical records. In addition, there are Massachusetts state laws and U.S. federal laws which prohibit discrimination in certain circumstances based on genetic test results.

  1. This protects people from health insurance discrimination and employer discrimination.
  2. To read more about this, visit Genetic Information Nondiscrimination Act,
  3. Where can I learn more about genetic testing? Please click to learn more about genetic testing.
  4. Learn more about the Center for Cancer Risk Assessment and find out what it means to have an inherited risk for cancer.

: Genetic Testing Frequently Asked Questions
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What is considered high risk for Down syndrome?

Higher-chance result – If the screening test shows that the chance of the baby having Down’s syndrome, Edwards’ syndrome or Patau’s syndrome is higher than 1 in 150 – that is, anywhere between 1 in 2 and 1 in 150 – this is called a higher-chance result.
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Is baby genetic testing worth it?

Prenatal genetic screening can be a useful tool to help the doctor and patient decide to pursue an invasive diagnostic procedure (which carries risk) or help decide if an invasive procedure is not necessary (helps to avoid risk).
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How accurate is genetic testing pregnancy?

Additional Information for Health Care Providers – The FDA recommends that health care providers also be aware of the positions of relevant professional societies, including the American College of Obstetricians and Gynecologists (ACOG), the Society for Maternal-Fetal Medicine (SMFM), and the American College of Medical Genetics and Genomics (ACMG):

These medical professional societies recommend that prenatal genetic screening should be discussed and offered to all patients regardless of their age or risk for a chromosomal abnormality. Patient education is emphasized in order to support informed decision making about whether to accept or decline screening. Emphasis is placed on education surrounding the positive predictive value of NIPS tests and the appropriate use of cell-free DNA tests as screening and not diagnostic tests. ACMG specifically recommends against testing for aneuploidies (missing or extra chromosomes) other than those involving chromosomes related to Down syndrome (21), Edwards syndrome (18) and Patau syndrome (13). ACOG does not recommend the use of NIPS tests to detect microdeletions.

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Published studies also strongly support the importance of performing confirmatory diagnostic testing to determine whether or not the fetus truly has a chromosomal abnormality following a positive screening test result. The scientific literature related to the use of NIPS tests from laboratories, including 25 peer-reviewed publications covering 13 studies evaluating more than 10,000 individuals undergoing NIPS, indicates that the NIPS tests evaluated generally perform well for ruling out disorders caused by chromosomal abnormalities.

The scientific literature generally report high negative predictive values, greater than 99.9% when calculated, for the NIPS tests studied. This means that the fetus is very likely not to have a chromosomal abnormality if the test returns a negative result. However, the literature confirms that the reliability of positive screening results is limited, particularly for microdeletions.

Reliability of positive screening results in these studies was best for Down syndrome, with a positive predictive value of about 90%, meaning that one in 10 positive results are not confirmed as Down syndrome. However, reliability of positive screening results was far lower for microdeletions, with the positive predictive value ranging from about 2% to 30%, depending on the condition.
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Does genetic testing show autism?

Genetic testing and autism spectrum disorder – If your child is diagnosed with ASD, the doctor might refer your child for genetic counseling and testing. Genetic testing looks for causes of ASD but cannot be used to diagnose ASD. Some people with ASD have syndromic ASD, meaning that they have other specific features in addition to having ASD, such as looking different from other people in the family or having birth defects.

Your child or another family member has syndromic ASD; A family member has an ASD-related genetic change found through genetic testing; or Multiple family members have ASD.

The most commonly ordered test for people with ASD is called a chromosomal microarray (CMA). This test looks at chromosomes to see if there are extra or missing parts that could cause ASD. CMA finds a genetic cause in 5% to 14% of people with ASD who have the test. In addition, children with ASD should be checked for genetic disorders that can cause ASD, including the following:

Fragile X syndrome : This disorder is one of the most common causes of intellectual disability. Fragile X syndrome affects about 1 in 7,000 males and about 1 in 11,000 females. About 0.5% of people (1 in 200) with ASD have fragile X syndrome. Testing for fragile X syndrome is recommended for all people with ASD. Rett syndrome : This disorder mainly affects females. About 4% of females with ASD have Rett syndrome, Rett syndrome testing should be considered for females with ASD.

If CMA and genetic testing do not find a cause for ASD, whole exome sequencing might be recommended. Whole exome sequencing looks for genetic changes in the parts of DNA that act as instructions for making proteins. Whole exome sequencing finds a cause in 8% to 20% of people with ASD who have the text.

  1. After genetic testing, genetic counseling is important to help you understand the test results and what they mean for your child and family.
  2. Genetic testing results can give doctors useful information about how to treat your child with ASD and which family members might be more likely to have a child with ASD.

Even if you don’t have a family history of ASD, talk to your child’s doctor if you have concerns about your child’s development.
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How long does it take to get genetic testing results pregnancy?

When Are the Results Available? – Blood screening results usually are ready within a week or two. Ultrasound results can be immediate. When both the blood test and ultrasound are done, doctors usually calculate the results together. This is called a combined first trimester screening,

Not all doctors calculate a woman’s risk this way. Some wait until after a woman has had other screenings in the second trimester. This is called an integrated screening, Other practitioners don’t do first trimester ultrasounds, instead determining a woman’s risk using the results of her first trimester and second trimester blood screenings.

This is called a serum integrated screening, How your doctor calculates your results depends on your age, health risks, and the services available at the provider’s office.
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What are the 3 most common chromosomal abnormalities?

Some of the most common chromosomal abnormalities include: Down’s syndrome or trisomy 21. Edward’s syndrome or trisomy 18. Patau syndrome or trisomy 13.
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Does genetic testing reveal Down syndrome?

How accurate are screening tests for Down syndrome? – Prenatal Genetic Diagnosis and Screening Services offers a screening test for Down syndrome, trisomy 13 and trisomy 18. “This new screening test, offered to women with the highest risk for having a child with Down syndrome, is 99 percent accurate in screening for Down syndrome,” says Dr.

  • Mennuti. “This means if 100 women were to have this test, 99 of the 100 would be detected.
  • The test can be performed as early as 10 weeks of pregnancy.” The screening test measures the amount of DNA from chromosome 21 in a pregnant woman’s blood.
  • Cells of fetuses with Down syndrome have an extra 21st chromosome so they release more chromosome 21 DNA into the maternal blood when broken down.

This causes a higher than expected amount of chromosome 21 DNA in the mother’s blood which can then be measured. The results are usually available about 10 days after the sample is drawn. Parents who learn their child is at high risk for an inherited chromosomal condition, such as trisomy 21 have the option to pursue an invasive diagnostic test like amniocentesis and chorionic villus sampling (CVS).
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Who is at high risk for chromosomal abnormalities?

Errors during dividing of sex cells (meiosis) – Meiosis (my-OH-sis) is the process in which sex cells divide and create new sex cells with half the number of chromosomes. Sperm and eggs are sex cells. Meiosis is the start of the process of how a baby grows.

  1. Normally, meiosis causes each parent to give 23 chromosomes to a pregnancy.
  2. When a sperm fertilizes an egg, the union leads to a baby with 46 chromosomes.
  3. But if meiosis doesn’t happen normally, a baby may have an extra chromosome (trisomy), or have a missing chromosome (monosomy).
  4. These problems can cause pregnancy loss or health problems in a child.

A woman age 35 years or older is at higher risk of having a baby with a chromosomal abnormality. This is because errors in meiosis may be more likely to happen as a result of the aging process. Women are born with all of their eggs already in their ovaries.

The eggs begin to mature during puberty. If a woman is 35 years old, the eggs in the ovaries are also 35 years old. You may be referred for genetic counseling or testing if you’re age 35 or older when you are pregnant. Men make new sperm ongoing. So age doesn’t increase the risk for chromosome abnormalities for older fathers.

But some newer studies suggest that rare abnormalities do occur.
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What is the most common genetic defect?

About Cystic Fibrosis Cystic fibrosis (CF) is the most common, fatal genetic disease in the United States. About 30,000 people in the United States have the disease. CF causes the body to produce thick, sticky mucus that clogs the lungs, leads to infection, and blocks the pancreas, which stops digestive enzymes from reaching the intestine where they are required in order to digest food.

Mutations in a single gene – the Cystic Fibrosis Transmembrane Regulator (CFTR) gene – causes CF. The gene was discovered in 1989. Since then, more than 900 mutations of this single gene have been identified. In normal cells, the CFTR protein acts as a channel that allows cells to release chloride and other ions.

But in people with CF, this protein is defective and the cells do not release the chloride. The result is an improper salt balance in the cells and thick, sticky mucus. Researchers are focusing on ways to cure CF by correcting the defective gene, or correcting the defective protein.

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Gene Therapy Research Offers Promise of a Cure for Cystic Fibrosis Gene therapy offers great promise for life-saving treatment for CF patients since it targets the cause of CF rather than just treating symptoms. Gene therapy for CF had its start in 1990, when scientists successfully corrected faulty CFTR genes by adding normal copies of the gene to laboratory cell cultures.

In 1993, the first experimental gene therapy treatment was given to a patient with CF. Researchers modified a common cold virus to act as a delivery vehicle – or “vector”- carrying the normal genes to the CFTR cells in the airways of the lung. Subsequent studies have tested other methods of gene delivery, such as fat capsules, synthetic vectors, nose drops or drizzling cells down a flexible tube to CFTR cells lining the airways of lungs.

  1. Researchers are now testing aerosol delivery using nebulizers.
  2. But finding the best delivery system for transporting normal CFTR genes is only one problem that scientists must solve to develop an effective treatment for CF.
  3. Scientists must also determine the life span of affected lung cells, identify the “parent cells” that produce CFTR cells, find out how long treatment should last and how often it needs to be repeated.

The first cystic fibrosis gene therapy experiments have involved lung cells because these cells are readily accessible and because lung damage is the most common, life-threatening problem in CF patients. But scientists hope that the technologies being developed for lung cells will be adapted to treat other organs affected by CF.

  • Genetic Research May Lead to New Drugs to Treat Cystic Fibrosis Another research breakthrough offers a promising approach to treating cystic fibrosis.
  • Researchers at the University of Washington’s Genome Center and at PathoGenesis Corporation have completed a genetic map for the Pseudomonas aeruginosa bacterium.

This bacterium is the most common cause of chronic and fatal lung infections for people with CF. Scientists hope to use their knowledge of this bacterium’s genetic sequence to develop innovative drugs for treating infections caused by P. aeruginosa. Gene Database Speeds Research As the amount of information about CF grows, scientists have recognized the need to share their research findings.

Mutations in a single gene – the Cystic Fibrosis Transmembrane Regulator (CFTR) gene – causes CF. The gene was discovered in 1989. Since then, more than 900 mutations of this single gene have been identified. In normal cells, the CFTR protein acts as a channel that allows cells to release chloride and other ions. But in people with CF, this protein is defective and the cells do not release the chloride. The result is an improper salt balance in the cells and thick, sticky mucus. Researchers are focusing on ways to cure CF by correcting the defective gene, or correcting the defective protein. Gene Therapy Research Offers Promise of a Cure for Cystic Fibrosis Gene therapy offers great promise for life-saving treatment for CF patients since it targets the cause of CF rather than just treating symptoms. Gene therapy for CF had its start in 1990, when scientists successfully corrected faulty CFTR genes by adding normal copies of the gene to laboratory cell cultures. In 1993, the first experimental gene therapy treatment was given to a patient with CF. Researchers modified a common cold virus to act as a delivery vehicle – or “vector”- carrying the normal genes to the CFTR cells in the airways of the lung. Subsequent studies have tested other methods of gene delivery, such as fat capsules, synthetic vectors, nose drops or drizzling cells down a flexible tube to CFTR cells lining the airways of lungs. Researchers are now testing aerosol delivery using nebulizers. But finding the best delivery system for transporting normal CFTR genes is only one problem that scientists must solve to develop an effective treatment for CF. Scientists must also determine the life span of affected lung cells, identify the “parent cells” that produce CFTR cells, find out how long treatment should last and how often it needs to be repeated. The first cystic fibrosis gene therapy experiments have involved lung cells because these cells are readily accessible and because lung damage is the most common, life-threatening problem in CF patients. But scientists hope that the technologies being developed for lung cells will be adapted to treat other organs affected by CF. Genetic Research May Lead to New Drugs to Treat Cystic Fibrosis Another research breakthrough offers a promising approach to treating cystic fibrosis. Researchers at the University of Washington’s Genome Center and at PathoGenesis Corporation have completed a genetic map for the Pseudomonas aeruginosa bacterium. This bacterium is the most common cause of chronic and fatal lung infections for people with CF. Scientists hope to use their knowledge of this bacterium’s genetic sequence to develop innovative drugs for treating infections caused by P. aeruginosa. Gene Database Speeds Research As the amount of information about CF grows, scientists have recognized the need to share their research findings. To facilitate this sharing of information, the Cystic Fibrosis Foundation funds (CFFT) located at The University of North Carolina Chapel Hill. The center is becoming a repository for data derived from gene expression studies. By pooling information, researchers hope to accelerate the process of finding a cure for CF.

CF has a variety of symptoms, including very salty-tasting skin, a persistent cough and excessive appetite but poor weight gain. The “sweat test” – which measures the amount of salt in sweat – is the standard diagnostic test for those with symptoms. A high salt level indicates CF.

  1. But one in 31 Americans – more than 10 million people – are symptom-less carriers of the defective CF gene and can pass on the defective gene to their children.
  2. To develop CF, a child must inherit a defective gene from both parents.
  3. If both parents are carriers, there is a 25 percent chance that each child they conceive will have CF, and a 50 percent chance that the child will be a carrier.

The purpose of carrier testing – a laboratory test done on a sample of blood or saliva – is to see if a couple is at risk for giving birth to a child with CF. Carrier testing is not infallible. It cannot detect all of the CF gene mutations. In rare cases, a person can have a normal test result and still be a CF carrier.

  • If both parents are carriers, they may want to consult with a genetic counselor for help in deciding whether to conceive or whether to have a fetus tested for CF.
  • Prenatal testing for CF can be done around the 11th week of pregnancy using chorionic villi sampling (CVS).
  • This involves removing a tiny piece of the placenta.

Or, the fetus can be tested with amniocentesis, around the 16th week of pregnancy. In this procedure, a needle is used to take amniotic fluid surrounding the baby for testing. Since CF cannot be treated before birth, the purpose of prenatal testing is to prepare parents to care for a baby with special health needs, or to make a decision about terminating the pregnancy.

CF has a variety of symptoms, including very salty-tasting skin, a persistent cough and excessive appetite but poor weight gain. The “sweat test” – which measures the amount of salt in sweat – is the standard diagnostic test for those with symptoms. A high salt level indicates CF. But one in 31 Americans – more than 10 million people – are symptom-less carriers of the defective CF gene and can pass on the defective gene to their children. To develop CF, a child must inherit a defective gene from both parents. If both parents are carriers, there is a 25 percent chance that each child they conceive will have CF, and a 50 percent chance that the child will be a carrier. The purpose of carrier testing – a laboratory test done on a sample of blood or saliva – is to see if a couple is at risk for giving birth to a child with CF. Carrier testing is not infallible. It cannot detect all of the CF gene mutations. In rare cases, a person can have a normal test result and still be a CF carrier. If both parents are carriers, they may want to consult with a genetic counselor for help in deciding whether to conceive or whether to have a fetus tested for CF. Prenatal testing for CF can be done around the 11th week of pregnancy using chorionic villi sampling (CVS). This involves removing a tiny piece of the placenta. Or, the fetus can be tested with amniocentesis, around the 16th week of pregnancy. In this procedure, a needle is used to take amniotic fluid surrounding the baby for testing. Since CF cannot be treated before birth, the purpose of prenatal testing is to prepare parents to care for a baby with special health needs, or to make a decision about terminating the pregnancy. Additional Resources for Cystic Fibrosis Information

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: About Cystic Fibrosis
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Can genetic testing show autoimmune diseases?

For a printable version of the April CE Story and test go HERE or to take test online go HERE, For more information, visit the Continuing Education tab. LEARNING OBJECTIVES Upon completion of this article, the reader will be able to: 1. Describe the human leukocyte antigen (HLA) system and how different variants of HLA are associated with specific autoimmune or autoflammatory diseases.2.

  • Summarize how genetic parameters are now an integral part of routine autoimmune diagnostics using DNA microarrays.3.
  • Describe the disease characteristics and genomic variants associated with celiac disease, rheumatoid arthritis, ankylosing spondylitis, and psoriasis.4.
  • Discuss how HLA genotyping plays a role in solid organ transplantation, hematopoietic stem cell transplantation, and transfusion practice for platelet refractoriness patients.15 The human leukocyte antigen (HLA) system is a complex of genes responsible for the regulation of the immune system.

HLAs feature a high level of genetic polymorphism, which enables the immune system with a selective advantage against the diversity of antigens that a host may be exposed to. Different variants of HLA genes have been associated with specific autoimmune or autoinflammatory diseases such as celiac disease (HLA-DQ2 and DQ8), rheumatoid arthritis (HLA-DRB1), ankylosing spondylitis (HLA-B27), and psoriasis (HLA-CW6).
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What are three reasons someone may get a genetic test?

What Does Pregnancy Genetic Testing Test For Genes are found in chromosomes and are made up of DNA. We inherit genes from our parents. Our gene structure dictates how our body grows and regulates. When genes are normal, they work properly. When genes are abnormal or damaged, they can lead to disease.

These are called gene mutations, or changes. Some changes run in families. These happen by chance and are called hereditary or inherited diseases and conditions. A gene mutation can be the sole cause of disease. However, most diseases occur from a mix of genetic and environmental factors. Genetic testing looks at your genes to check for any mutations.

The test is done with a sample of blood, saliva, or tissue. There are several reasons why you might do genetic testing.

To diagnose a disease or a type of disease. To determine the cause of a disease. To determine treatment options for a disease. To find your risk of getting a certain disease that possibly can be prevented. To find your risk of passing a disease to your children. To screen your embryo, fetus, or baby.

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How accurate is genetic testing for disease?

Give it to Me Straight. Are Genetic Tests Accurate? – Unfortunately, there is no simple answer to this question. All genetic tests are not created equal. There are two key parts to any genetic test and a lab can be accurate in both, one or neither. The first part is detection:, Can the lab actually detect a change in a specific gene? The second is interpretation: If a lab finds a change, will it be interpreted correctly? Let’s talk a little more about detection.

This is complicated because not all tests are designed to find every genetic change. Your genes are something like a book. If you were asked to find typos in a book but only told to look on pages 1, 10, and 27, you would miss some that appear elsewhere. That doesn’t mean you didn’t do a good job looking.

You may have found every change on each of those pages and had 100% accuracy—but if the other pages have typos, you would not have detected them. Another issue is the problem of false positives. One study, published in the journal Genetics in Medicine, found that 40% of variants included in the raw data of one direct-to-consumer genetic testing company were false positives.

  1. You may be wondering how this can be possible.
  2. There are several explanations.
  3. The first is that no genetic test is perfect.
  4. There is always the potential for lab error.
  5. Samples get mixed up or contaminated and mistakes happen.
  6. This may occur more often when testing companies use labs that aren’t held to high standards.

For example, when you get genetic testing through a healthcare provider, your provider will use labs that go through a rigorous and thorough certification process to ensure the accuracy and reliability of test results. While there are some direct-to-consumer tests that use labs like this, there are many which do not.

This leaves a lot of room for error and a lack of oversight to prevent it. What’s more, a lot of genetic results can be interpreted in different ways, Different labs use different protocols for interpreting such test results. So while a test itself may have correctly identified a variant in a particular gene, the way that a particular lab interprets it may be incorrect.

For example, one lab may say a certain variant likely causes an increased risk for prostate cancer, while another may lab say the same variant likely doesn’t raise this risk. It all depends on what data the lab is using to support its interpretation. Many of the common variants we know of today for diseases like Duchenne muscular dystrophy were discovered by doing genome-wide association studies (GWAS).

Researchers gathered patients who had the same characteristics and sequenced all their genes to look for sequences that are more common among the selected group than in the general population. In the case of Duchenne muscular dystrophy, they saw “hot spots” in one gene on the X chromosome and were able to associate the disease with this gene, which is now called DMD.

It becomes more complicated when we think about complex traits like which diet will work best for you or what flavors you will and won’t like. These traits are not determined by single genes, but rather the interaction of many genes. Different tests may be looking at different combinations of these hot spots and therefore give entirely different results.

  • What’s more, many of these complex traits are also influenced by environmental factors and lifestyle choices.
  • Some tests may be accurate in that they can correctly identify a variant if it is present, but they may still be incomplete.
  • Many direct-to-consumer genetic tests do not analyze every gene, or even assess every gene associated with a certain health condition.

For example, you may have seen the option to receive results for BRCA1 and BRCA2 from 23andMe. These two genes are associated with an increased risk for breast and ovarian cancer. However, 23andMe looks at only three “hot spots” in these genes commonly found in people of Ashkenazi Jewish ancestry, although there are many more places in the gene that can be affected.

While this is clearly explained in the report, it may easily be overlooked. This test can accurately tell you if you do or do not have one of the three variants tested for, but may be missing a variant somewhere else in the gene. All this means that the accuracy of genetic testing is hard to pin down.

So how can you be sure you’re getting the information you want, and that it’s even right? The best thing you can do is work with a certified genetic counselor. These healthcare providers are trained to gather your personal health history as well as your family history and determine what testing is appropriate for you based on your goals.

They can then work with other qualified healthcare providers to interpret your genetic results and incorporate them into your medical management, if necessary. If you’ve already had genetic testing through a direct-to-consumer test and want a clearer understanding of what the results, a genetic counselor can help.

This type of information can be complicated and confusing. Luckily, many genetic counselors are willing and able to look through these reports with you, help you interpret them and recommend any other testing that may be necessary to meet your needs.
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