By Kara Stoler
Kara Stoler (KS), a genetic counsellor in Johannesburg, spoke to the Cape Jewish Chronicle about genetic conditions that are common amongst South African Jews.
According to Kara, about one in three Jewish people carry a common Ashkenazi genetic condition. These conditions display autosomal recessive inheritance and so carriers do not display symptoms and there is typically no family history. A BRCA1/BRCA2 gene mutation follows a dominant pattern of inheritance so just one family member could pass it to the next generation.
CHRONICLE: What are the most common genetic conditions that have a high prevalence among the Jewish population?
KS: There are 27 conditions that we test for among Ashkenazi and Sephardi Jews. These are conditions that are fatal in early childhood or would be seriously life-threatening conditions – ones that would significantly impact the affected individual’s quality of life.
The ones more commonly known among South African Jews are cystic fibrosis and Tay-Sachs Disease (recessive conditions). The carrier rate for a Tay-Sachs mutation is fairly high, with 1 in 25 Jews being a carrier. Similarly, with cystic fibrosis the carrier rate is 1 in 29.
The BRCA1 and BRCA2 mutations are dominant genes that are also prevalent among Ashkenazi Jewish women (and men). The incidence is high among Ashkenazi Jewish women relative to the rest of the population: 1 in 40 Ashkenazi Jewish women carry it, while only 1 in 400 have it among the wider female demographic.
We must remember, too, that men can get breast cancer and may also be at an increased risk for other cancers, so the BRCA mutation should not be seen as only affecting women.
CHRONICLE: How would someone know that they may carry one of these genes?
KS: We recommend that every couple considering starting a family should undergo Ashkenazi genetic testing. Generally, there is no family history of a condition unless a baby is born affected through two carrier parents. This is why it’s so important for any couple embarking on the path to parenthood to go through a testing programme. Genetic testing can help identify vulnerable couples who are at risk of having affected offspring with a fatal or life-threatening condition.
Couples who carry mutations for the same condition can have healthy offspring through preimplantation genetic testing which is performed in conjunction with IVF. A couple’s embryos will be screened for a specific condition and only healthy embryos, without the mutation, are implanted. Other unaffected embryos will then be frozen for future use so that a couple is confident that they will deliver a healthy baby.
Genetic counselling is also important to determine an individual’s risk for other conditions such as an inherited cancer syndrome. (Ovarian cancer is also a common cancer associated in women who carry a BRCA mutation.) If there is a strong family history of cancer, typically at younger ages, with a number of family members and related cancers, this may put someone at a higher risk for carrying
a genetic mutation.
The story of Gabriella Blumberg and the BRCA genetic mutation is an example of this: she chose genetic counselling because she knew she was at risk of breast cancer since others in her family had developed it previously. The tests we did proved that she carries the genetic mutation, and so this allowed her to take preventative action to reduce the risk of developing breast cancer. (See box below).
CHRONICLE: In the case of a woman who carries the BRCA gene, is an elective mastectomy the only preventative measure that can be taken?
KS: Today, screening through mammograms and sonar would help with the early identification of the disease – and treatment at that stage can be highly successful. A woman at risk should probably have screening tests every six months to ensure early detection if the disease does indeed present. It is important for an individual to consider prophylactic risk-reducing surgery if they carry an inherited cancer gene.
Everyone’s risk factor is different and that is why it is important to speak to a genetic counsellor to determine your risk. The counsellor will refer you to a specialist medical practitioner if appropriate.
Eva, a young poet uncovers her high genetic risk for breast cancer and navigates the decision to remove her breasts preventatively. How much will this affect her identity?
Capetonian Jordy Sank has partnered with Gabriella Blumberg from Johannesburg in a new film venture, ‘Volle Bors’ (BARE), produced by Sanktuary Films. The short film is based on Gabriella’s personal story: her discovery that she carries the BRCA genetic mutation – which has a high prevalence among Ashkenazi Jews – and the nuance of emotions that came with making tough decisions relating to preventative measures to remove the risk of being afflicted with breast cancer.
With her own experiences informing the fictional story she wrote, the film premiered recently at the Silwerskermfees – where it won BEST SCORE – and will be available for the public to view on Showmax.
Gabriella had always been aware that breast cancer was prevalent in her family, going back many generations. She watched family members battle with breast cancer and, when she was 18, she decided to go for genetic counselling, which confirmed that she tested positive for the BRCA1 mutation.
Gabriella is passionate about making films that start important conversations and she hopes that this film will encourage people to educate themselves about their family history and take agency over their own bodies. She is not trying to advocate that everyone takes the same path that she has taken, but rather to open the dialogue so that everyone can make informed decisions.
Follow @sanktuaryfilms to stay up to date with film screenings.
• Published in the October 2023 issue – Click here to start reading.
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