Why is one person susceptible to an infection while another one isn’t? By using microarrays for DNA sequence analysis, one can rapidly identify mutations (e.g., SNPs, deletions, and amplifications) in “susceptibility genes”  that influence an individual’s risk of acquiring disease. For instance, mutations in the CCR5 human coreceptor for HIV have been demonstrated to endow resistance to viral infection.

Researchers anticipate using resequencing microarray technology to quickly screen for these mutations in large populations and understand an individual’s predisposition to the disease. Additional “susceptibility genes”, such as the HIV receptor CCR2, can readily be included on the array and sequenced in the same single assay. Because scientists are able to select any portion of the genome, including long regions of continuous sequence or different combinations of genes for resequencing, they can explore all of the major genetic contributions to susceptibility and its monitoring.

While resequencing “susceptibility genes” is one method of understanding host predisposition, microarrays are now able to simultaneously genotype tens or hundreds of thousands of SNPs, offering a new possibility for predicting infectious disease risk. These high-density genome scans and genome-wide association studies are normally performed to understand the genetics of complex diseases and drug response.

But, the same types of studies can be designed to understand infectious disease susceptibility. By examining large groups of equally-exposed individuals—some who develop disease, others that don’t—scientists will be able to identify genes associated with resistance or predisposition towards disease.