2012 National DNA Day Online Chatroom Transcript

This is just one question from an archive of the National DNA Day Moderated Chat held in April 2012. The NHGRI Director and many genomics experts from across NHGRI took questions from students, teachers and the general public on topics ranging from basic genomic research, to the genetic basis of disease, to ethical questions about genetic privacy.

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What kind of DNA Mutation is the most serious?
     Weiyi Mu: I am a second-year genetic counseling student in the Johns Hopkins University/NHGRI Genetic Counseling Training Program. I became interested in genetics when I was in middle school and have been studying science ever since! As a genetic counseling student, I see patients with all different kinds of genetic or genetics-influenced conditions from Down syndrome to breast cancer. I learn about how genes affect their conditions and also learn to how to help them understand and live with their conditions. The seriousness of the mutation depends on (1) how it affects the gene it changes and (2) how important that gene is. For example, a nonsense mutation will completely stop the protein from being formed. If this protein was important in forming muscles (for instance, like in Duchenne muscular dystrophy), muscles will not be formed properly and a person with this mutation can have a very shortened life (because muscles are also in the heart and lungs). On the other hand, if there was a mutation in a gene that is important for tasting a certain type of flavor, a person with that mutation may not taste the same way as people without the mutation, but it would not otherwise affect his or her health. Another kind of serious mutation is when huge pieces of DNA are missing or added. This can even be an entire chromosome that is missing or added. A chromosome may have thousands of genes on it, so these types of mutations can really affect someone's health! An example of a condition with an extra chromosome is Down syndrome.
McDowell Intermediate High School in PA (10th grade student)

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