Genetic research is the study of human DNA to find out what genes and environmental factors contribute to diseases. If we find out what causes disease, we can better detect disease, better treat disease and hopefully even prevent disease from happening in the first place!
Nearly every disease we know of has a genetic component. Depending on the disease, the genetic contribution may be very large, very small, or, most often, somewhere in between. Researchers are studying nearly every disease to find out how genetic factors may contribute. We inherit our genes from our parents. Genes tell our bodies how to develop and function. There are about 25,000 genes that make the things our bodies need to develop and work. Each gene is made up of DNA. DNA is a very long code that uses only 4 letters. We know that variations in this code can alter the way a gene works. Sometimes the variation is in only one letter. This is referred to as a SNP. Most SNPs don’t cause problems. They either contribute to the normal differences from one person to another, or have no known effect at all. However, a small number of SNPs can alter the way the gene works and contribute to disease. Sometimes the DNA code is altered by pieces that are missing or are extra. The missing or extra pieces may be as small as a one letter or as large as thousands. Depending on what is missing or extra, this may also contribute to health issues.
Research involving families
Diseases such as autism, Alzheimer disease, heart disease, and cancer are common. Approximately 1 out of every 110 children is affected by autism, 1 in 10 adults will develop Alzheimer disease and 1 in 3 adults will develop cancer in their lifetime. Since these are common diseases, we expect to see that sometimes more than one person in a family may have the condition. However, when a family health history is taken, some families have a much higher number of people with a certain complex disease than other families do. For example, imagine a family in which a great-grandmother, grandfather, and mother (three generations) were all affected by Alzheimer disease. We known that closely related members of a family share many of their genes. In fact, we share half our genes with our parents, brothers and sisters, and children! It is likely that there are genes shared by members of that family that are involved in the development of Alzheimer disease. By involving this family in genetic research, scientists can learn which genetic differences are shared by the family members who have Alzheimer disease, but not found in others in the family. These genetic differences narrow down the region where a gene might be. This technique of finding genes using a family is called a family study, or linkage analysis.
Research involving large groups of people
Another way of doing genetic research is to do DNA testing on two large groups of people. One group of people has the disease, and the other does not. Those who do not are sometimes referred to as controls. Most often, the people in this type of study are not related to one another. This technique is called association. Association studies rely on the use of thousands to millions of SNPs (described above) in our DNA. If you could imagine our DNA as huge roadmap, SNPs would be like mile markers on the highway. Scientists know the location of millions of SNPs throughout human DNA. Scientists also know that at the location of these SNPs, there is variation in the DNA code from one person to the next. For example, at one SNP, one person may have a letter T (thymine), while another person has a G (guanine). If a particular DNA SNP is seen more often in those with a disorder, such as autism or Alzheimer disease, it is possible that this SNP is associated with or is near an area of DNA that is associated with the disorder. Association studies are very large projects and require the participation of hundreds to, preferably, thousands of people with a disease and without a disease.
Research involving candidate genes
When trying to find genes that contribute to a disorder, sometimes researchers will look specifically at candidate genes. Candidate genes are those that researchers think might be involved in a disorder either because of what they do, and/or because they are located in an area of the DNA that looks interesting based on family studies or association studies described above. For example, some of the candidate genes that have been looked at for autism are known to be involved in behavior or language.
Diversity in genetic research is crucial!
It is important for all ethnic groups to be represented in genetic research. This is because people of the same ethnic group share many of the same changes and variations in their DNA with each other that they may not share with people of a different ethnic group. If only one ethnic group is involved in genetic research, we learn only about the variations in DNA that are associated with disease in that particular ethnic group.
When genetic research searching for genes involved in breast cancer was just beginning, most women who participated in genetic research studies were Caucasian. That research lead to the discovery of two very important genes (BRCA1 and BRCA2) that are now known to put women who have mutations in these genes at high risk for breast and ovarian cancer. It was found out that many mutations in the BRCA genes can lead to a high risk for cancer. However, only those mutations that were common in the Caucasian population were discovered through the initial research projects. This meant that when a non-Caucasian woman was tested for mutations in the BRCA genes by her doctor, there was a high chance that the results would not be conclusive. After many years of additional research, genetic testing for breast cancer has greatly improved for non-Caucasian women and testing of these genes is now more beneficial for them. By including all ethnic groups in genetic research, all ethnic groups can benefit from the findings of genetic research.
How to get involved in genetic research
At the John P. Hussman Institute for Human Genomics at the University of Miami’s Miller School of Medicine, our research efforts are aimed to ensure that all people, regardless of race or ethnicity, are able to benefit from the research that is done at our institute. Our researchers invite participation from the diverse South Florida community as well as larger national and international communities. Participation in a research study at the HIHG is completely voluntary. While details may vary from study to study, trained members of our team will conduct family history interviews and diagnostic evaluations. In addition, our team members will retrieve a blood or saliva sample. Some research studies ask for one-time participation only, while others request that participants are involved in several appointments. There is no cost or payment for your participation. We maintain the highest standards of confidentiality for all participants and families. Your private information is not given out to other researchers or companies. Your participation will help us to better understand the genetic and environmental causes of diseases and disorders, which may eventually lead to improved treatments and prevention methods, and hopefully a cure. Some research studies offer compensation for participation.
To learn more about the individual research studies ongoing at the HIHG, please visit the HIHG website (www.hihg.org). If you are interested in participating in one of our research projects, please visit the HIHG website or contact us:
Email: hihginfo@med.miami.edu
Telephone: 1-877-686-6444
Fax: 305-243-2396