About Carrier Screening For JGDs

Most severe Jewish genetic disorders are recessive, and therefore can be prevented entirely via carrier screening

What is carrier screening?  

Carrier screening (or carrier testing) involves taking a small saliva sample and testing it to identify if a person has any changes in a gene associated with a  genetic disorder. If one or more changes are found, then they are considered to be a ‘carrier’ for that condition.  

Most JGDs are recessive. Carriers of recessive disorders are not typically affected themselves but are at increased risk of having a child affected by the disorder, if their partner is also a carrier of the same condition.  A couple in which both partners are carriers for the same disorder is known colloquially as a ‘carrier couple’ and they have a 1 in 4 chance with every pregnancy of having an affected child.  

Carrier screening helps couples to identify if they have a high risk of passing on a severe genetic disorder and enables them to consider the various options available to reduce the chances of having an affected child.  

It is an important step in family planning and allows you to take control and make informed choices that can protect the health of your future children. 

Why carrier screening is so important?  

Having a child with a severe Jewish genetic disorder (JGD) is utterly devastating – not just for the child but for the whole family. Typically, babies with recessive genetic disorders are born to parents with no known family history of that condition. 

1 in 5 people of Jewish origin is a carrier of one of the Jewish genetic disorders we test for 

Without realising it, you and your partner may be carriers for the same disorder and at real risk of passing this on to your child. You cannot change your carrier status but knowing if you are a carrier enables you to manage the risk of your children inheriting a severe JGD. Even if both you and your partner are carriers of the same disorder, it is still possible to have your own healthy children. 


Who should consider screening?  

Screening for Jewish genetic disorders is relevant for anyone aged over 16 who has at least one Jewish grandparent, whether they are Ashkenazi or Sephardi/Mizrahi. 

It is particularly recommended for people who are planning to start or expand their existing family. 

Couples who have already completed their family can also be tested to enable them to inform their own children if there is any increased genetic risk. 


What are the options for ‘carrier couples’?

There are several options for carrier couples to help manage their risk of having an affected child. Some of these are listed below.

Genetic counsellors are healthcare professionals who are trained to support carrier couples in exploring these options and deciding which is best for them. Any carrier couples identified via the Jnetics Clinic are provided all the onward support and advice necessary from our dedicated genetic counsellor. .  


Myths and Facts of JGD carrier screening

Myth– I have no family history of a genetic condition so there is no need to be screened.  

Fact–  Most children with recessive genetic disorders are born to families with no known history of the condition. Screening is still important as future generations can still be at risk. 


Myth– Both parents of an individual have to be Jewish for screening to be relevant to them.  

Fact –Screening is recommended for anyone who has at least one Jewish grandparent. 


Myth– Screening is just for people with Ashkenazi ancestry. I’m Sephardi so don’t need to get screened  

Fact –Screening is important for anyone of Jewish origin, whether their ancestry is Ashkenazi, Sephardi/Mizrahi or mixed. Different disorders are relevant to these different groups, but nonetheless screening is important for all 


Myth– We already have two healthy children so there is no way we can be carriers and don’t need to bother getting screened.  

Fact – For carrier couples, with each pregnancy there is a 1 in 4 chance of their child being born with a genetic disorder. As such, it is not uncommon for these couples to have one or more healthy children before then having an affected child. 


Myth– I have had Tay-Sachs screening and I am not a carrier so I don’t need to be screened again. 

Fact – Whether you are a Tay-Sachs carrier or not has no bearing on your risk for being a carrier for the other Jewish genetic disorders. Screening for these disorders will identify if you are at risk of these other conditions that disproportionately affect Jewish people. 


Myth– My sibling was screened and they were not a carrier: therefore, there is no reason for me to be screened.  

Fact – Even if your sibling screens negative, there is still a chance that you may be a carrier for a genetic disorder as we only share 50% of our genes with our siblings.