Genetics and Carrier Screening
All couples with ANY Jewish ancestry, including interfaith couples, should have pre-conception carrier screening for all Jewish genetic diseases.
If both parents are carriers of the same disease, there is a 1-in-4 chance, with each pregnancy, that their child will be born affected with that disease, a 2-in-4 chance that their child will be a carrier of that disease and a 1-in-4 chance that their child will be neither affected nor a carrier of that disease.
In an autosomal recessive condition (such as most Jewish genetic diseases), persons who inherit only one mutated gene show no signs of disease, but persons who inherit two mutated genes will be affected by the disease.
What it Means to be a Carrier
A carrier is an individual who does not develop the disease, but can pass on the gene with a mutation to his or her children.
In the case of the Jewish genetic diseases, which are termed “autosomal recessive,” one carrier parent can pass the carrier mutation, but both parents must be carriers of the same disease to have an affected child.
How is Screening Done?
Carrier testing for all of the Jewish genetic diseases by DNA analysis can be done using blood or saliva. For Tay-Sachs disease screening, enzyme analysis using blood in addition to DNA analysis is required. For Alpha and Beta Thalassemia, a complete blood count (CBC) is done first.
The tests should be ordered and the results should be read by a knowledgeable doctor or genetic counselor trained to interpret genetic tests.
After several weeks a report is issued with results. It is important to note that all test results should be reported by a physician with experience in genetic screening or a genetic counselor.
Where is Screening Done?
Currently there are several ways to obtain screening – your doctor’s office (usually OB/GYN), Hospital based Medical Genetics Programs or online genetics education, counseling and screening programs.
Who Should be Screened? In a Couple, Who is Screened first?
In a couple where both partners are Jewish, the usual practice is to screen the woman first, generally at her OB/GYN office. If she is found to be a carrier, her partner should then be screened for the disease or diseases for which she carriers.
If only one partner is of a Jewish background, that partner should be screened first. If he or she is found to be a carrier, the other partner must be screened for the disease or diseases for which the Jewish partner carries. Genetic Counseling is recommended.
If the couple is already pregnant, both partners should be screened at the same time.
In the case of a single woman wishing to become pregnant, or same-sex partners where donor egg or sperm is being used it should come from a donor who has been screened for Jewish genetic diseases.
When is the Best Time to be Screened?
Screening before pregnancy is optimal. This allows a carrier couple the greatest number of options. It is important to note that if the couple discovers their carrier status once they are already pregnant their only option, if the fetus is affected, is to continue or to terminate the pregnancy.
If the woman is already pregnant, both partners should be screened at the same time. If they are both found to be carriers, this allows for earlier fetal testing and decision-making.
It is also important to note that fetal testing for Jewish genetic diseases is not possible unless the parents are already screened and their particular genetic mutations are identified.
Although every insurance plan is different, many cover testing for Jewish genetic diseases. Contact your insurance company for coverage information. A medical genetics program can be helpful in determining coverage. If screening is not covered, the JGDC may be able to provide referrals to low cost screening options or provide a letter of necessity for your insurance company.
In 2008 the Genetic Information Non-discrimination Act of 2008 (GINA) was signed into law. It’s a federal statute that protects American from being treated unfairly due to their genetic inheritance.
As of May 2009, health insurers may not deny or limit coverage or charge higher premiums based on a person’s genetic information. As of November 2009, employers may not use genetic information to make decisions about hiring, firing, promotion or job placement.
There are multiple options that enable carrier couples to build a healthy family. Each couple needs to make their own informed decision, based on the disease or diseases for which they are carriers and other personal considerations.
Genetic counselers can explain these options in depth. As you will see, it is best to know your carrier status before starting a family, so you can make informed decisions based on accurate genetic information.
• A carrier couple may choose to become pregnant and test the fetus early in the pregnancy.
In the case of a couple who would choose to get pregnant on their own, the couple should test the fetus early in pregnancy. This can be done by chorionic villus sampling (CVS) at 10-12 weeks, or an amniocentesis at 14- 16 weeks. In order to test the fetus, the parents’ carrier status must be known.
If the fetus is affected with the disease the couple carries they can choose to terminate the pregnancy or bring it to term. In the case where the couple chooses to give birth to an affected child having prior knowledge of the disease is extremely important. Information about the disease your child carries can help you to be aware of medical necessities and interventions that the child may require at birth.
• A carrier couple may choose in-vitro fertilization (IVF) with pre-implantation genetic diagnosis (PGD).
The egg is fertilized outside the body and embryos are tested at a very early stage for the disease carried by the parents. Only unaffected embryos are implanted in the womb.
• A carrier couple may choose to use egg or sperm from a non-carrier donor.
The donor should be screened for the Jewish genetic diseases.
• A carrier couple may choose to adopt.
• A carrier couple may choose not to have children.
• A carrier may choose not to marry another carrier of the same disease.
If you or your partner have any Jewish ancestry, or are an interfaith couple, it is important that you ask to have pre-conception carrier screening for the Jewish genetic diseases.
If you are already pregnant, it is important to discuss screening with your doctor as soon as possible.
Tell you doctor about:
• Your plans to become pregnant
• You and your partner’s family background, whether Ashkenazi, Mizrahi or Sephardic.
• Any family history of genetic diseases.
If you have been screened before, and your test results are available, bring them to your appointment.
If you don’t have a doctor or if your doctor doesn’t offer genetic screening and counseling, you should contact a hospital-based medical genetics program in your area. Click here for a national listing, or search for a genetic counselor in your area at NSGC.org.