CJG Blog

Center for Jewish Genetics blog

Should I Get Screened Again?

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DNAimage2By Lilli Arbetter

Jewish genetic testing originated about 30 years ago with a successful carrier screening program for Tay-Sachs disease. As a result, there has been a significant drop in the prevalence of this disease amongst the Jewish population and, interestingly, most children born with Tay-Sachs disease today have non-Jewish parents. However, although there are fewer babies born with Tay-Sachs today, the carrier frequency rates have not changed. The need for genetic testing ultimately remains the same and is crucial to improving society’s overall health and wellbeing and, in particular, Jewish people. Since the development of testing, the panel for Jewish genetic diseases continues to increase in the number of conditions for which one can be screened, ultimately helping to reduce rates of other harmful diseases.

Although our DNA does not change, technology does. Our capacity for genetic testing has advanced from simple genotyping, which determines the genetic variants that an individual possesses, to genetic sequencing, which examines the exact order of DNA base pairs. In simpler terms, genotyping highlights specific spelling errors in a sentence, while genetic sequencing checks the whole sentence for mistakes, including grammar and spelling. As the capacity for genetic testing has increased (indicated in the increased detection rate from 90% to 99%), a large number of genetic conditions have been added to the panel.

Our genetic counselor, Melissa Ramos, offers a piece of advice:

"Similar to other genetic tests, technology continues to improve, and we are learning more about genetic conditions every day. It's the same for carrier screening. It's no longer the "one and done" type of test that it used to be."

This does not mean that you must get tested prior to each pregnancy. However, recognizing changes in family health history and keeping up to date with available options for pregnancy, especially if you are a carrier, is extremely important. By simply checking in with your OBGYN or doctor to discuss any changes/additions to the panel, you are maximizing your options when it comes to having a healthy pregnancy.

If you are considering getting screened, I recommend that you consider our carrier screening program. The Sarnoff Center offers an online, on-demand carrier screening program that you can complete from the comfort of your own home. Here is the link to the registration page and if you have any further questions, please contact Carol Guzman at 312-444-2847: jewishgenetics.org/get-screened


Fragile X Awareness Month

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ChromosomepuxxleBy: Lilli Arbetter

July is Fragile X Awareness Month, which is devoted to bringing attention to Fragile X Syndrome (FXS). FXS is a disease that leads to intellectual disability (the leading genetic cause of autism spectrum disorder) and is prevalent in the Ashkenazi Jewish population.  

What causes FXS? The fragile X mental retardation 1 gene (FMR1) makes a protein called the fragile X mental retardation protein (FMRP), which is needed for typical brain development. Those who have FXS do not make this protein. In the FMR1 gene, there is a section of the DNA pattern, CGG, that is repeated many times. A small number of repeats (5 to 44) is normal; however, the following occurs as the number of repeats increase: 

  • 45 to 54 repeats: Those within this range of repeats are called intermediate carriers and do not have FXS. Their offspring are not at risk for FXS, but future generations may be at risk. 
  • 55 to 200 repeats: Those within this range of repeats are called premutation carriers. They do not have FXS but have a premutation. Premutation carriers have an increased risk for adult-onset symptoms, such as tremor-ataxia syndrome, premature ovarian insufficiency, and neuropsychiatric disorders. A woman within this range of repeats has a 50% chance of passing the premutation or full mutation on to their daughter or son. A man within this range will have a daughter with a premutation, but his son will not be affected. 
  • 200+ repeats: Those with 200+ repeats have a full mutation and therefore, have FXS.  

Children of any sex can have FXS and its associated symptoms; however, the symptoms are often more severe in males. Since females have two X chromosomes, the working copy of the FMR1 gene can compensate for the inherited non-working FMR1 gene copy. This means that although they may have FXS, their symptoms are often not as severe. However, males only have one X chromosome, so if they inherit a damaged copy, they do not have another gene to compensate for the mutated one and will have more severe symptoms.  

For men who are carriers of FXS, the disorder tends to skip generations. When a father passes the premutation on to his daughter, she can become a carrier and her children can inherit the disorder. Unlike men, for women who are carriers, their mutation can expand and get bigger with each generation.  

Anyone considering FXS testing should consult with a genetic counselor. A diagnosis of FXS can provide an explanation for a child’s behavioral problems and allow a family to obtain treatment for the child to reach their full potential. Although there is no cure, there are options such as medication, therapy, and other treatment/support that a genetic counselor can help advise. 


Proactive Choices for you and your Baby's Health

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BabyImageBy Lilli Arbetter

Any parent-to-be wants to provide their child with a healthy life. That is where prenatal genetic tests can help. There are a wide variety of genetic tests available, such as: 

  1. Diagnostic Testing: diagnoses a condition or disease  
  2. Carrier Screening: tests parents-to-be to determine their risk of having a child with a recessive disorder, such as cystic fibrosis or Tay-Sachs disease  
  3. Aneuploidy Screening: screens for chromosomal abnormalities  

These types of tests are offered at various points pre-conception or during pregnancy to provide parents with information to make the most informed decisions regarding their child’s health. Parents can talk with a genetic counselor to quantify risk and help determine the best course of action for them to take with family planning or to plan for intervention early in a baby’s life, if needed. In this way, preconception and prenatal genetic testing can improve a baby’s quality of life.  

In the rare instance that both members of a couple are carriers, they can opt to undergo preimplantation genetic testing and in-vitro fertilization, if they learn this information prior to pregnancy. Embryos are then screened for the genetic condition that the partners carry and, through in-vitro fertilization, only embryos without the condition are implanted into the uterus for pregnancy. Preimplantation genetic testing ultimately lowers the chance of the genetic transmission of a specific abnormality, further reducing the risk of miscarriage and the number of embryo transfers required to conceive, if caused by that specific abnormality.   

Genetic testing does not stop once the baby is born. Newborn screening is done after birth to identify childhood onset conditions. Prior to a baby being discharged from the hospital, a few drops of blood are taken from the baby’s heel and are screened for endocrine, metabolic, and genetic disorders, as well as congenital heart defects. The goal is to pick up on conditions early in a baby’s life, as early detection followed by intervention when a diagnosis is received can be crucial for a child to reach full potential. By having your newborn screened, one can be proactive and get their child proper treatment or medical attention sooner for an otherwise yet to be known condition.   

I encourage you to attend the Sarnoff Center’s event titled “Decoding Genetic Tests for Parents-To-Be" on Thursday, July 15th from 12-1 PM CT on Zoom to learn more about different genetic tests. Genetic counselor Melissa Ramos will go into detail regarding the different types of genetic tests as well as genetics 101 and how Covid-19 has affected the world of prenatal care. Whether planning for pregnancy now or in the future, this presentation will leave you feeling knowledgeable about the variety and role of genetic testing offered and the value of being tested.  

Link to register: juf.org/decode  



Affordable, Accessible Genetic Screening in Illinois

Our affordable, accessible carrier screening program uses advanced technology to provide comprehensive screening for Jewish and interfaith couples. Visit our Get Screened page to learn more and register.


Do You Know What's In Your Genes?

What is the most valuable gift you can give to your family? The gift of good health! There are many health conditions that run in families. Knowing your family health history can alert you to the potential risk for a variety of genetic disorders . Talk to your relatives for warning signs and assess your risk for hereditary cancers.

Did you know: Ashkenazi Jews are 10 TIMES more likely to have BRCA mutations, which significantly increases lifetime risks for hereditary cancers, so what does this heightened risk mean for you? Click here to learn more .