Why are there Jewish genetic diseases?
Historically, members of individual ethnic groups have tended to marry and start families with other members of the same ethnic group. Because of this, over time, certain genetic conditions have become more common within specific populations.
There are a number of genetic diseases that are more common in individuals with Jewish heritage, be they Ashkenazi, Persian, Sephardic, or Mizrahi Jews. These diseases are usually recessive, meaning that an individual must have two non-working copies of a particular gene to be affected with the condition. Carriers are healthy individuals with one working copy and one non-working copy of a gene. When carriers of the same disease have children together, there is a 25% chance of having an affected child with each pregnancy. A non-working copy of a gene can be passed down through many generations before a child is born with that disease; therefore, most families are not aware that they are carriers for a certain disease because there is no family history of that disease.
It is important to understand that genetic diseases do not discriminate, it is not specific to individuals of Jewish background. All ethnic groups have certain conditions that are more common within its members. For example, Sickle Cell Disease is more common in individuals of African descent. There are also some genetic conditions, such as Cystic Fibrosis, Spinal Muscular Atrophy, and Fragile X, which are common across many ethnic groups and for which testing should be considered for anyone planning to have children.
It is important to understand that this has nothing to do with religion.
Because risk is based on ethnicity, not religion, even those who were not raised with a Jewish identity or have only one ethnically Jewish grandparent may be carriers for a Jewish Genetic Disease.
In the Jewish community, we see different diseases in Ashkenazi versus Sephardic and Mizrahi Jews. For this reason, it is important to know your background in order to get appropriate carrier screening. In Ashkenazi Jews, genetic testing is somewhat simpler, because the same conditions are carried in Jews of Eastern European descent, regardless of the country of origin. In Sephardic and Mizrahi Jews, testing is a bit more complex, as some diseases are common in the Mediterranean and some are more common in the Middle East. There are even differences between Middle Eastern regions, so the most appropriate testing for Persian Jews, for example, may not be the best choice for other Mizrahi Jews.
How do you get screened for Jewish genetic diseases?
There are many options available for carrier screening for Jewish genetic diseases. A blood or saliva sample is required to receive information crucial to building a healthy family. However, because there are many different testing options, being informed is a necessity.
The right test for you depends on your background. For example, if your family is Persian, you are unlikely to be a carrier of a disease that is common in Ashkenazi Jews. If one of your parents is Sephardic and the other is Ashkenazi, you will want to make sure the test includes conditions common in both populations. If you have one or more grandparents who were not ethnically Jewish, a larger pan-ethnic panel may be appropriate, as there are genetic diseases among the general population.
You can get testing through your primary care doctor, your OB/GYN, or a genetic counselor. A consult with a genetic counselor can be helpful to learn more about genetic diseases, the testing process, and in order to ensure that you are receiving a test that is appropriate based on your ethnicity, family history, as well as your partner’s. This is particularly important if you are concerned about any diseases that you know run in your family.
Because there are many different testing options, being informed is a necessity.
Another option is home-based testing. This may be directly through a lab, or through a non-profit organization, such as JScreen.org. The process involves requesting a test kit online, which is mailed to you. Then you collect a saliva sample and mail the kit back. This is not direct-to-consumer testing; it is clinical testing, just done from your home. When you request a kit, you provide your physician and insurance information. Whatever method you choose, there are some important questions to ask:
- Do you offer different test panels for different populations?
- What diseases are included in the test panel?
- Does it include diseases common in Persian, Sephardic and/or Mizrahi Jews, or does it only include diseases common in Ashkenazi Jews?
- Does it include only diseases common in Jewish populations or is it a pan-ethnic test?
- Does it test for mutations common in particular populations or does it look for all possible mutations?
Often, health insurance covers carrier screening. Contact the genetic screening service or your insurance carrier for information.
What if I test positive as a carrier for a Jewish genetic disease?
If you’re being screened for Jewish genetic diseases, there can be a lot of uncertainty about what a positive test result could mean.
First of all, it is important to understand that testing positive is not necessarily a problem. In fact, we are all carriers for several genetic diseases. That’s right – we are all carriers. But being a carrier does not mean we have the disease.
Within each ethnic group, there are certain recessive conditions that are known to be more common. Among Ashkenazi Jews, there are 19 to 38 conditions that are considered common. Among Sephardic and Mizrahi Jews, there are 17. And among Persian Jews, there are 4. There are also recessive conditions that are common in the general population, such as Spinal Muscular Atrophy or Cystic Fibrosis.
We are all carriers for several genetic diseases.
But being a carrier does not mean we have the disease.
Carriers are not affected by the disease and never will develop symptoms, but they will always be carriers. They typically show no signs that they are a carrier and there is usually no family history of the condition.
But, if you’re a carrier for a disease, does that mean if you give birth to a child, that baby will be affected? Most of the time the answer is no. Both you and your partner must be carriers of the same recessive condition to have an affected child. When two people who are both carriers of the same condition have children together, there is a 1 in 4 (25%) chance of each child being affected with the disease. It is possible to put the odds on your side
What if my partner tests positive?
If you and your partner are planning on having children, you should both be screened for common recessive conditions.
If one partner is a carrier for a recessive condition, it is essential that the other partner have comprehensive testing for that condition. Genetic counselors are experts in this and it would be helpful to speak to one in order to ensure that the correct test is ordered. Remember that when someone tests positive, they are not affected by the disease and will not develop any symptoms. They are only carriers.
Both of you may be carriers of some genetic disorders, but if you’re not carrying the same diseases, it won’t affect the health of your child.
Now let’s consider another scenario, in which both of you test positive, though not for the same disease. If you are both carriers for different recessive conditions, there is no risk of your children being affected with one of the disorders, though they may be carriers of one or both. This is why there is peace of mind in knowing your status. Both of you may be carriers of some genetic disorders, but if you’re not carrying the same diseases, it won’t affect the health of your child.
Finally, there’s the third scenario – learning that you are both carriers for the same condition. Does that mean your child will be born with the disease? Here are the odds: When two people who are both carriers of the same recessive condition have children together, there is a 1 in 4 (25%) chance of each child being affected with the disease.
Knowledge is power. And thanks to medical advances, there are many options available to help couples avoid having a child affected with a disease.
If we are both carriers for the same disease, can we still have a healthy baby?
When it comes to Jewish genetic diseases, some people would rather not know their carrier status because knowing can be overwhelming. But the truth is, the sooner you know your status, the more options you will have in terms of family planning.
As we’ve discussed previously in the series, if both you and your partner are carriers for the same genetic disorder, there will be a 1 in 4 (25%) chance of each of your children being affected by the disease.
There are reproductive options available to you – prevention before pregnancy and diagnosis during pregnancy.
Then what? Should you not have children? Do you go ahead and get pregnant and keep your fingers crossed? It’s understandable that you would be confused about how to proceed. You should know, though, that there are reproductive options available to you. These options fall into two categories – prevention before pregnancy and diagnosis during pregnancy. Decisions on how to proceed are very personal and are based on multiple factors specific to the couple. Seeking support, counseling, and guidance through this process is essential.
- In-vitro fertilization (IVF) with preimplantation genetic diagnosis (PGD): This method uses the couple’s own eggs and sperm to create embryos. The embryos are tested for the disease, and only unaffected ones are implanted.
- Use of donor egg or sperm from a non-carrier donor
Diagnosis during pregnancy options:
- Genetic testing using chorionic villus sampling (CVS) or amniocentesis
- If the fetus tests positive for the disease, parents may choose to use the information to prepare for the birth of an affected child or terminate the pregnancy
It is possible to have a healthy baby. And knowing your carrier status is the first step in ensuring the health of your future family.
When is the right time to get tested?
As long as you are over 18 years old, you can be screened for Jewish genetic diseases, but the right time to actually do the test is a very personal choice. For example, you may be single and want to know your results before pursuing a new relationship. Perhaps you’re in a relationship, but want to know your status before you start getting more serious. Or you may want to wait until you’re in a committed relationship and thinking of having children.
Despite your personal motivations for testing, the best time to be screened is before pregnancy. This way, if both partners find out they are carriers of the same disease, they will have time to learn more about the disease and make informed decisions as they plan their life together. Meeting with a genetic counselor can be extremely helpful to guide couples through this process. By having this information before pregnancy, many more options for family planning become available to the couple.
The best time to be screened is before pregnancy.
Even if one’s ethnic background is not Jewish, it’s important to know that genetic conditions exist in the general population. So whether your background is Persian, Ashkenazi, Mizrahi or Sephardic – or if you’re not Jewish or unsure of your background because you are adopted – knowing your carrier status as soon as possible is the first step in ensuring the health of your future family.
Who should get screened?
Jewish couples planning on having children. If you are Jewish and planning on having children, you should get screened for Jewish genetic diseases. That’s because there are a number of genetic diseases that are more common in individuals with Jewish heritage, be they Ashkenazi, Persian, Sephardic, or Mizrahi Jews. When both partners are carriers of the same disease, there is a 25% chance of having an affected child with each pregnancy.
Interfaith couples planning on having children. For interfaith couples, if the Jewish partner is found to be a carrier for a genetic disease, then the non-Jewish partner should also be screened for the same disease.The genetic diseases that are more common among Jews are not confined to this population. These diseases are found in other ethnic groups as well.
There are a number of genetic diseases that are more common in individuals with Jewish heritage.
Couples in which one or both partners are adopted. Those who are adopted and unsure of their ancestry should be screened for genetic diseases before having children. Genetic diseases can be found in the general population — not just among people with Jewish backgrounds.
Couples who already have healthy children but intend on having more. Individuals of Jewish ancestry who already have healthy children despite not being tested previously should consider screening if they are planning on having more children in the future.
Anyone of Jewish ancestry. Sometimes, people who have no intention of becoming pregnant will also get tested to determine if a gene runs in the family. If a person is a carrier, whether they have decided to have children or not, it is important that they share this information with relatives and encourage them to be screened as well. In this way, families can work together to help inform members if there is a risk for certain genetic diseases running in the family.
What is the difference between blood and saliva testing?
There are two ways to screen for carriers of Jewish genetic diseases: blood testing and saliva testing. Both methods are viable and comprehensive options for carrier screening.
Blood testing. Most people are familiar with blood tests – a small amount of blood is drawn from your arm, and the sample is sent to a laboratory for analysis. Carrier screening through a blood sample can be done at a physician’s office or a medically supervised screening event.
Saliva testing. Saliva testing requires the individual to spit into a tube, and the saliva sample is then sent to a laboratory for analysis. Saliva testing can be done at a physician’s office, at a medically supervised screening event, or at home with a carrier screening kit.
Both are viable. From both types of samples, blood and saliva, the laboratory is able to extract DNA for genetic analysis. We have the same DNA in every cell in our body, therefore, the accuracy is the same for both methods.
We have the same DNA in every cell in our body, therefore, the accuracy is the same in both methods.
What about Tay-Sachs? Tay-Sachs is a metabolic disease that is caused by an enzyme deficiency in the body. One way to screen for Tay-Sachs is through enzyme analysis. This looks at the level of a specific enzyme in a person’s body to determine if he or she has Tay-Sachs. Enzyme analysis is possible through a blood sample only. Historically, enzyme analysis has been the preferred method for Tay-Sachs screening. When low enzyme levels were detected, that person would then go through genetic testing to confirm that he or she was a carrier. Science has come a long way, and genetic analysis now includes a technology called DNA sequencing. This technology allows for a high detection rate of mutations in a gene that could cause disease. DNA sequencing is possible with both blood and saliva. For Tay-Sachs disease, DNA sequencing detects more than 98 percent of carriers.
The important thing to remember is that, whether your background is Ashkenazi, Mizrahi, Sephardic or Persian, screening for Jewish genetic diseases and those of the general population — with either blood or saliva — will help ensure the health of your future family.
Should prospective fathers get screened?
Both mothers and fathers can be carriers for genetic diseases, and it is important for both partners to be aware of their risks. It is often prospective mothers who first become aware of the issue and seek genetic screening. However, it is equally important for prospective fathers to be informed and seek genetic screening. If both partners are carriers of the same genetic disease, there is a 1 in 4 or 25% chance with each pregnancy of having a child with the disease.
Carrier screening can be beneficial not just for the couple but also for each of their families. Knowing your carrier status can provide valuable information for relatives, because this means that they are at risk for being a carrier of the same disease. This is important information to pass on to siblings and cousins, especially those who are also in the stage of starting a family and having children.
Both mothers and fathers can be carriers for genetic diseases, and it is important for both partners to be aware of their risks.
While it is important for prospective mothers and fathers of Jewish descent – whether Ashkenazi, Mizrahi, Sephardic or Persian — to seek out genetic counseling and screening, those in interfaith relationships and in the general population can be carriers as well.
Carrier screening can be done by blood or saliva. If you’re planning on being a father, speak to a genetic counselor about the right carrier screening test for you – to ensure the health of your future family.
How do I talk to my family about genetic diseases?
Our genes are the basis of what connects us to our family members. We all inherit family traits because genes are passed down from generation to generation. Some genes that we inherit, however, can be responsible for causing or increasing risk for certain diseases. That is why it’s so important to be aware of your family history and take note of any traits that may put you or your relatives at risk.
One way to start is by building a family tree and interviewing family members to collect information.
Understandably, it can be difficult to talk about genetic diseases with family members. These conversations can be sensitive topics that can bring up difficult memories and, therefore, can be difficult to discuss. In addition, there is often limited health information available for older generations.
One way to start the process is by building a family tree and interviewing family members to collect information. Collect information on yourself, your parents, your siblings, your grandparents, and extended family. Be sure to be sensitive when asking about medical issues any individuals may have had, or how certain family members passed away, and explain to family members that this is an important part of the family health history. Once you create a record of your family history you can share it with other relatives as well as your healthcare providers to better inform your care. As a bonus, you’ll have a family tree that many generations can treasure and use to benefit their own healthcare.
Tips on collecting information.
- Engage your family members in a conversation and hear their personal stories. Photographs and other family memorabilia can facilitate your discussion and jog their memories.
- Probe deeper into their answers with questions that begin with “How” or “Why,” but if they are uncomfortable with these questions, try framing your discussion with “Tell me about…” so they feel less pressured.
- Family members may not know the names of certain diseases. If so, ask them to describe the symptoms instead.
- If you are adopted, ask your adopted family if they know anything about your birth parents. You can also check with your adoption agency if it is possible to see their records.
Why should both partners be screened for genetic diseases?
Anyone can be a carrier for one or more genetic diseases, and it is important for both partners in a relationship to be aware of their carrier status. We are all carriers for certain genetic conditions. Most of the time, this is not a problem – a carrier will not develop the disease. The risk of having an affected child arises only when both partners are carriers of the same disease. If both partners are carriers of the same genetic disease, there is a 1 in 4 or 25% chance with each pregnancy of having a child with the disease. That’s why it’s crucial for both partners to be tested.
What if the couple is interfaith? It’s still important for both partners to be tested because the genetic diseases that are more common among Jewish individuals are not confined to this population. These diseases are found in other ethnic groups as well.
Knowledge is power. Knowing both your and your partner’s status will provide you more information and options for having a healthy baby.
There may be instances where one partner knows that he or she is a carrier of a certain disease. It is important to share this information and discuss it openly both in the relationship and with healthcare providers in order to ensure that the right tests are ordered for the other partner. Furthermore, providers – like genetic counselors – can help inform and educate the couple about the process and the options that are available to them.
Remember, there is no reason to fear this information. Knowledge is power. Knowing both your and your partner’s carrier status will provide you more information and options for having a healthy baby. If you are interested in learning more about carrier screening or feel unsure about testing and have questions, find a genetic counselor in your area or visit our website www.genetestnow.com.
How do I create a family tree with my family’s health history?
You will want to tailor your questions based on your family, but here are some sample questions to get you started.
- Where and when were you born?
- Where did you grow up?
- Did you experience any health conditions as a child?
- Do you have brothers or sisters? Did they have any health conditions as children? At what age did symptoms begin?
- Did any of your siblings pass away during childhood? Do you know of any aunts, uncles or cousins who passed away during childhood?
- Where and when were your parents born?
- Where and when were your grandparents born?
- What health conditions affected your parents and/or grandchildren?
- What kinds of medications do they, or did they, take?
- Do your parents have brothers or sisters? Do they have any health conditions?
The drawing below is called a pedigree, and is one example of how to draw and organize your family tree. Squares represent males and circles represent females. Include important information like names, dates of birth or approximate ages, health information, age at death, and cause of death. Depending on the size of your family and how many generations you include, your family tree may be much larger.