How Will Personalized Medicine Impact the Practice of Gastroenterology?

Abstract

I exchange for a drop of saliva and as little as $299, consumers can access predictions about their future health ased on DNA sequence variations occurring throughout their enome. Tantalizing. But is this the personalized medicine that ealth care providers and patients envision as the future pracice of medicine? Personalized medicine uses information about an individul’s genes, proteins, and environment to inform health care ecisions that could improve clinical outcome. This notion of ersonalized medicine appears attainable with the recent seuencing of the entire human genome (Human Genome Projct), the publication of HapMap (a catalogue of common single ucleotide polymorphisms [SNPs] linked to traits and disorers), and technological advances conferring the ability to rapdly analyze an individual’s genome. Genomic sequencing proides the most comprehensive genetic information about an ndividual because it detects all types of genetic variations and utations, but currently is impractical in clinical care because omplete genome sequencing and analysis could cost as much s $68,500, at least according to one company (it cost $350,000 n 2007).1 Most direct-to-consumer (DTC) genetic testing companies instead use state-of-the-art microarray technology to rapidly identify SNPs that generate a less complete snapshot of an individual’s genetic variations. Although specific SNPs themselves generally are not believed to be responsible for causing a trait or disorder, their presence may be used to predict a genetic predisposition to certain traits. After analyzing an individual’s DNA, a DTC company can provide the consumer with a list of predictions (or relative risks) of specific disorders, based on more than 1000 DNA variants already linked to specific diseases or traits in the published literature. For-profit companies claim they can make predictions about the likelihood of developing a multitude of disorders or traits, ranging from esophageal cancer to baldness. The Genetics and Public Policy Center has compiled a list of the companies and the traits and disorders each claims to detect.2 One company maintains it can identify the “inherited and endowed inborn talents of a child from the genetic makeup of his/her DNA” (Map My Gene, Singapore; www.mapmygene.