Jewish Health

Genetics and inheritance 1

The health conditions discussed on this site occur with a higher than average frequency amongst those of Jewish ancestry - especially Ashkenazi Jews - than in the general population. If a condition is more common in one particular ethnic group, it is likely to be genetic or have a genetic component. For some conditions, including Tay Sachs, MSUD (Maple Syrup Urine Disease), familial dysautonomia and Cystic Fibrosis, specific genes in which inherited mutations cause the condition have been clearly identified. These conditions are sometimes called ‘single gene disorders’ and it is relatively easy to test for them once they have been identified. With the exception of Torsion dystonia (participant 19) they are inherited as autosomal recessive genetic disorders. This means that a person must have inherited faulty copies of the gene from both parents to develop the disease. A person who has only one copy of a faulty gene but does not develop the condition themselves is called a ‘carrier’ because they can pass the gene on to their children.

Things are more complicated for conditions such as breast cancer and ovarian cancer or Crohn’s disease. Multiple genes are likely to contribute to a person’s overall risk of developing these conditions and environmental factors such as diet and lifestyle also play an important part. As both cancer and bowel disease are common health problems anyway, participants who were affected by these conditions were often unsure whether there was a genetic component to their illness.
In some cases, receiving a genetic diagnosis encouraged people to look more thoroughly for patterns of illness across the generations.
‘Being a carrier’ meant different things to different people. For many, the revelation that they had a ‘faulty gene’ came ‘out of the blue’. Others were vaguely aware of health problems in previous generations but had not realised that there was a medical label or indeed a genetic basis for it. One man with Factor X1 Deficiency, a recessive disorder causing haemophilia, had never heard of it and only found out that he had the condition after a liver biopsy led to life-threatening blood loss. Another family with a history of Factor X1 Deficiency described how a there was quite a lot of variation in how badly family members were affected by the faulty gene from one generation to the next*.
How people felt about carrying a ‘faulty’ gene was influenced by the type of condition, their family context and their stage in life. A couple who had their baby diagnosed with Cystic Fibrosis (CF) while still in the womb, were far less concerned about their status as carriers than about how the condition would affect their unborn child. Another woman who found out in pregnancy that she was a carrier for Tay Sachs was incredibly relieved when her husband tested negative, as it meant her baby and any future children they might have were not at risk of developing the disease, even though they might be carriers.
Others, who had completed their families before finding out that they were carriers described feeling guilty about passing on ‘faulty’ genes to the next generation. They worried about the right time to tell their children that they, too, might be carriers.
Some people felt a degree of stigma and guilt about having a genetic condition. A couple of people said they would make use of pre-implantation genetic diagnosis (PGD) - going through IVF and then testing the foetus before it is implanted to make sure it has not inherited the faulty gene copy – to ‘eradicate’ the faulty gene from the family line.

Several people saw it as a matter of personal responsibility in choosing to take a predictive test and find out their genetic status. They struggled to understand relatives who didn’t want to know.
However, one woman spoke about being a Tay Sachs carrier in quite positive terms, saying it was part of her identity - something that made her feel connected to a lineage of ancestors.

* A ‘low reading’ in relation to Factor X1 deficiency refers to the substance that makes blood clot in the case of injury. So the lower the Factor X1 reading, the longer it takes for blood to congeal and the higher the risk for even minor injuries to be life-threatening for that person. 

Last reviewed May 2019
Last updated June 2015.


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