Broader Lessons from Genetic Studies of the Ashkenazi Jewish Population

By: Dr. Inga Peters

Published: August 12th, 2012
Latest update: October 23rd, 2012

This year marks the 80th anniversary of the influential paper published by a Mount Sinai physician, Dr. Burrill Crohn, and his colleagues that for the first time characterized a disease associated with severe inflammation of the intestine. Patients with what was later named Crohn’s disease develop diarrhea, fever, stomach pain, and often lose weight. Crohn’s is now classified as an autoimmune condition in which the immune system attacks its own healthy tissue in the gastrointestinal tract, causing chronic inflammation. It affects young individuals, and, even though it is not curable, it can be treated and controlled by medications and surgery.

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While we know that exposure to pathogenic organisms can cause disease (e.g., stomach flu), little is known about whether there is a common core set of microbes (microbiome profile) that is shared between healthy people or individuals with the same disease. We already know that changes in diet, antibiotic treatment and various conditions, including obesity, may shift our normal bacterial balance. Small studies have shown a lower diversity of the gut microbiota found in Crohn’s disease patients compared to unaffected individuals, raising questions about the possible role of commensal bacteria in disease development. Moreover, the fact that the major genes found to be associated with Crohn’s disease are involved in the processing of microbial antigens and immune response further implicate commensal bacteria in the Crohn’s disease risk.

Despite preliminary data indicating substantial differences in gut microbial content between healthy individuals of different racial and ethnic backgrounds, no studies have compared a composition of the bacteria between Ashkenazim and non-Jewish Europeans. It should not be surprising if such differences exist, given the unique dietary and lifestyle traditions observed by Jews including kosher food and a mandatory hand-washing before meals (“netilat yadaim”) that could reduce exposure to infection. Therefore, under- or overrepresented microbiota in this population may help guide future efforts in developing novel treatments targeting commensal bacteria.

The use of isolated populations in genetic research has been demonstrated to be of special value by revealing how small inter-individual differences in their human genome sequence increase the chances of detecting mutations that are disease-associated. Therefore, to help advance our understanding of complex diseases, the Ashkenazi Genomic Consortium was established. The “Ashkenome” is a new collaborative initiative seeking to identify how the unique genetic make-up of this population contributes to various conditions, including diabetes, Parkinson’s disease, schizophrenia, or aging. This information, along with microbiome data, can be used in future studies of more diverse populations and help lead to early diagnosis, a better means of prevention, and novel treatments for complex diseases such as Crohn’s.

Inga Peter is the Associate Professor in the Department of Genetic and Genomic Sciences at the Mount Sinai School of Medicine. Her research interest is to identify variations in the human genome that can explain susceptibility to common diseases such as obesity, diabetes, and Crohn’s disease that can lead to early prevention and personalized treatment of these conditions. She graduated from Tel Aviv University and completed her training at Tufts University in Boston. She lives in Westchester County, NY with her husband and 3 sons.

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About the Author: Inga Peter is the Associate Professor in the Department of Genetic and Genomic Sciences at the Mount Sinai School of Medicine. Her research interest is to identify variations in the human genome that can explain susceptibility to common diseases such as obesity, diabetes, and Crohn’s disease that can lead to early prevention and personalized treatment of these conditions. She graduated from Tel Aviv University and completed her training at Tufts University in Boston. She lives in Westchester County, NY with her husband and 3 sons.