Question 2: Third Place

 

Excerpt from Julianna Hsing's winning essay

 

 

... The most serious problem with DTC genetic testing lies in the interpretation and use of these genetic results. Interpreting complex genetic data is not an easy matter for individuals without any genetic training because: 1) having the genetic trait or genetic susceptibility does not mean an individual will develop the disease; and 2) many common diseases, including heart disease and certain cancers, are polygenic –affected by more than one gene. These concepts are complex and not easily appreciated by consumers. Such complexity is largely related to the vast amount of germline genetic variation (genetic variation inherited in the lineage of the germ cells) (genome.gov; Gray, 2000). Most germ-line mutations occur in the form of single nucleotide polymorphisms (SNPs), which are DNA sequence variations that occur when a single nucleotide in the 3-billion-base human genome is altered (Gray, 2007). Some genetic variations are quite common in the general population (~10-25%), and not all individuals carrying the risk allele will develop the disease (Dong, 2008). For example, carrying a BRCA1 mutation increases a woman’s risk of developing breast cancer, but not every woman who carries this mutation will develop breast cancer—the penetrance is not 100% (Mavaddat, 2010). This is true because in addition to genetics, environmental exposure and the interactions between genes and the environment also impact on the probability of disease development. Furthermore, most chronic disorders, including diabetes and cancer, are polygenic, involving more than one gene (Coyle, 2009). Most DTC testing does not take into account other important risk factors, such as family history or past environmental exposures...