What Your Congregants Should Know

Chicago Center for Jewish Genetic Disorders

&

Children’s Memorial Hospital

In general, 1 in 3-5 Ashkenazi Jews is a carrier for at least one of these disorders

Some disorders are more common than others- carrier frequencies range from 1 in 15 to 1 in 149

Ways in which the disorders differ – Age of onset – many have early childhood onset– Degrees of severity – many are lethal– Treatment options – very few have effective treatment

Genetic testing is now available for almost all the disorders listed later

Ashkenazi Jewish genetic disorders represent a varied group of

conditions

GeneticsA gene…

Is made of DNA, the basic genetic material

Carries the chemical instructions to make all the proteins in the body

Has the instruction or “code” for one particular protein

We have two copies of most genes

What is a genetic mutation and how does it lead to disease?

A change in the DNA of a particular gene can result in an alteration of the genetic instructions.

Some genetic alterations are not harmful but are part of our genetic differences (for example, hair color and eye color).

An alteration in a gene can lead to disease by affecting the function of that gene.

Many of the Ashkenazi Jewish genetic disorders are inherited in a

recessiverecessive fashion

When both parents are carriers for the same disorder, they have a 25% chance in each pregnancy of having an affected child.

Facts about carrierscarriers of recessive genetic disorders

Every individual is estimated to be a carrier of 6-8 genes which can produce disease.

Carriers are generally not affected because they have a fully functioning copy of the disease gene.

Only when both copies of the gene are not functioning will an individual be affected with the disease.

Most carriers will have no family history of that genetic disorder.

Ethnicity&

Disease

Judaism is not only a religion and culture, but also a distinct ethnicity.

Certain ethnic groups have a higher risk for certain genetic conditions than the general population.

– Northern European Caucasians: cystic fibrosis

– African Americans: sickle cell disease

– Mediterranean ancestry: -thalassemia

Why does ethnicity determine disease risk?

Founder EffectA few individuals migrated and founded a new,

isolated population.

Within this group there was a founder who carried a

genetic mutation.

The group was then, by chance, different from the

population that the settlers came from.

For what diseases are SephardicSephardic Jews at increased risk?

Beta-thalassemia

Familial Mediterranean fever

Glycogen storage disease, type III

G6PD deficiency

What disorders are AshkenaziAshkenazi Jews at increased

risk for?Bloom’s syndromeCanavan diseaseCystic fibrosisFamilial dysautonomiaFanconi anemia, group CGaucher disease, type IMucolipidosis IVNiemann-Pick disease, type A Tay-Sachs disease

Dihydrolipoamide dehydrogenase deficiencyFamilial hyperinsulinismGlycogen storage disorder, type 1aJoubert syndromeMaple syrup urine diseaseNemaline myopathySpinal muscular atrophyUsher syndrome type 1FUsher syndrome type 3

Hereditary breast and ovarian cancer syndrome (Dominant inheritance)

Torsion dystonia (Dominant inheritance)

*Important note about the disorders

There is no set panel of Ashkenazi Jewish genetic disorders. Different labs screen for different panels of these disorders. Diseases listed in italics are explicitly recommended by American College of Medical Genetics (ACMG). The others on the right fit ACMG criteria except the last four. Please see the Chicago Center website, www.jewishgenetics.org, for more detailed information about the disorders.

To whom should screening be offered?

Carrier screening is available for disorders more common in the Ashkenazi Jewish population by looking for specific

mutations that are most common in this group.

Individuals with at least one Ashkenazi Jewish grandparent, or suspected Ashkenazi ancestry, should be offered screening.

Screening should still be offered to a Jewish individual even if his/her partner is not biologically Jewish, as none of these disorders are exclusive to the Jewish population.

What options are available to couples found to be at risk?

• Sperm or egg donation• Preimplantation genetic diagnosis• Prenatal diagnosis by amniocentesis or chorionic

villus sampling• Adoption• Choosing to accept the risk

How successful is carrier screening?

The Tay-Sachs Model

• One of the most successful screening programs for genetic disease

• Strong participation from the Jewish community

• Involvement of religious leaders

• Programs have been able to nearly eliminate Tay-Sachs disease from the Jewish population

Incidence of Classic Tay-Sachs Disease in U.S. and Canada

Incidence of Classic Tay-Sachs Disease in U.S. and Canada

1970 1980 1982 1983 1984 1985 1987 1989 1990 1991 1992 1993 1994 1995 1996

Year Ending

0

5

10

15

20

25

30

35

40

Num

ber o

f Ca s

es

Jewish

Non-Jewish

Incidence of Classical Tay-Sachs disease in the U.S. and Canada

A decrease in the number of affected individuals

DOES NOT mean a decrease in carrier frequency.

Why would someone choose not to be screened?

Lack of awareness about Tay-Sachs and other Ashkenazi Jewish diseases

Some people assume that there is no need to be tested if:

Parents were screened for Tay-Sachs—but we now screen for many more disorders.

Marrying someone who is not Jewish—but testing is still recommended for the Jewish partner.

Cost—Many insurance plans do not cover carrier testing.

Fear of stigmatization/effect on relationships

Dor Yeshorim A confidential genetic screening system used mainly by

Orthodox Jews for the purpose of preventing the transmission of Jewish genetic disorders

Participants do not receive their results, only their genetic compatibility with a potential marital partner.

Dor Yeshorim screens for a panel of Ashkenazi Jewish genetic disorders for approximately $200. If an individual has previously used this system, updates are available through the Dor Yeshorim Program.

Dor Yeshorim will not screen already engaged or married couples.

For more information about carrier screening or to find a local genetic counselor, please visit

www.jewishgenetics.org

The Center is a cooperative effort of Jewish United Fund/Jewish Federation of Metropolitan

Chicago and Children’s Memorial Hospital and is funded in part by the

Michael Reese Health Trust.