Genetic Diversity By Carol Guzman

Advancements and discoveries in genetic research and technologies intentioned to help all humans only benefit few. Since the completion of the Human Genome Project in 2003, researchers have sequenced the genomes of various populations all over the world (see: 1,000 Genomes Project). Yet little population-specific research has been conducted to advance the knowledge of disease and personalized medicine in minority groups.

Genome-wide associate studies (GWAS) allow scientists to study and identify genetic markers that are involved in human disease. GWAS compare one group of healthy individuals against a group of individuals affected by a specific disease. In these studies, scientists look at several small gene changes called single nucleotide polymorphisms (SNPs) in both sample populations. GWAS has been used to study genetic factors that contribute to many common, complex conditions such as diabetes, heart disease, and drug metabolism.  The small genetic differences found in the affected group versus the unaffected group help scientists identify genetic variants that may be associated with an individual’s risk of developing a specific disease. After GWAS are used to pinpoint genetic markers associated with diseases, scientists can use this information to guide drug development that treats the root cause of the disease rather than only treating the diseases’ symptoms.

According to a study conducted by Nature, of 2,511 GWAS involving 35 million participants, 81% of participants were of European descent. Of the 19% of non-European ancestry samples, African and Latin American ancestry, Hispanic people and native or indigenous people represented less than 4% of the participants the GWAS studies. Therefore, researchers are developing drugs and other targeted therapies based on disease-associated genetic markers that are typically found in only European populations. Failure to include minority populations results in undiscovered genetic variants associated to diseases. These exclusions make it impossible to make drugs that could treat the root causes of minority genetic variants.

However, finding genetic markers associated for a disease is not as easy as diversifying the population of those participating in the study. The small genetic differences that would be identified could also be natural genetic variation related to differences in race or ethnicity, as opposed to variants associated with a disease. Therefore, we must have global genomic studies to ensure that personalized medicine benefits all human populations. The National Institutes of Health is making a historic effort to gather data from more than one million people in the United States. Their All of Us Research Program will enable researchers to conduct genetic studies on various minority populations in the United States. Still, similar initiatives have yet to be seen on a global scale.

Genetic diversity also plays an important role in better understanding genes that are known to causes certain diseases, such as genes related to hereditary cancer risk. The Jewish population has an increased risk of having a gene mutation that leads to higher breast cancer risk. Knowledge of specific Jewish genetic variants has helped widespread hereditary cancer screening efforts within the Jewish community. African women are also more likely to develop breast cancer compared to the general population. However, it was only this year that University of Chicago conducted the first study focused on understanding genetic variants for breast cancer in African populations. Among African women, breast cancer is diagnosed at later stages, is more frequently a triple-negative disease, and is far more frequently fatal compared to women of other of other ethnicities.

While in some ways the Jewish population remains at the forefront of genetic screening we too suffer from the marginalization instituted from lack of diversity in genetic research. A clear example is the W1282X nonsense mutation of cystic fibrosis, a variant of CF that is highly prevalent among Ashkenazi Jews. This CF genetic variant affects 5-10% of CF cases worldwide. Researchers have created drugs that help 90-95% of CF patients with the most common CF mutations, but none have been made to help those suffering from CF by way of this particular nonsense mutation.

Modern day Jews come from various ethnic Jewish origins resulting in several Jews having different genetic variants of various diseases. By integrating minority populations in genetic studies to improve screening and genetic medicine, the scientific community benefits Jews and the world.