Cystic fibrosis is one of the many so called “Jewish genetic disorders” that are disproportionately common among Jews of eastern European (Ashkenazi) descent – as much as 20 to 100 times as common as in other populations. The genetic roots of these diseases also commonly cause multiple members of one family to be afflicted. Some of these diseases are severe and may result in early death of a child. Carriers of these diseases are typically healthy and symptomless. Carrier screening is available for these conditions, using a small blood sample.
Scientists believe that certain disorders tend to be more common among Ashkenazi Jews due to the "founder effect" and "genetic drift." Today's Ashkenazi Jews descended from a small group of founders. And for centuries, for political and religious reasons, Ashkenazi Jews were genetically isolated from the population at large.
- Founder Effect
The founder effect occurs when populations are started from a small number of individuals of an original population. Geneticists refer to this relatively small group of ancestors as founders. It is believed that most of today’s Ashkenazi Jews descended from a group of perhaps only a few thousand privileged Ashkenazi Jews that lived in Eastern Europe half a millennium ago.
Millions of people today can likely trace their ancestry directly to these founders. Thus, even if just a few founders had a mutation, the gene defect would become amplified over time.
- Genetic Drift
Genetic Drift refers to the increase in frequency of the genes for these disorders in this group. Because Ashkenazi Jews tended to marry within their community, the relatively high frequency of these genes among Jews was not spread to other communities and their concentration was not diluted by other genes from outside the community.
Most Common Jewish Genetic Disorders
1. Mendelian Disorders are the direct result of mutated genes
- Bloom Syndrome
- Canavan Disease
- Crohn's Disease
- Factor XI Deficiency
- Familial Dysautonomia (Riley-Day syndrome)
- Fanconi Anemia
- Gaucher Disease
- Mucolipidosis IV
- Niemann-Pick Disease
- Non-Classical Adrenal Hyperplasia
- Nonsyndromic Hearing Loss
- Tay-Sachs Disease
- Torsion Dystonia
2. Disease Predisposition Genes are disorders which result from the
combination of specific genes
- Breast Cancer (BRCA1 and BRCA2)
- Familial Colon Cancer
Some of these diseases may be severe and may result in early death of
a child. Carriers of these diseases are healthy and not affected with
the disease. Carrier screening is available for these conditions, using
a small sample of blood>