P2RX7 genotype association in severe sepsis identified by a novel Multi-Individual Array for rapid screening and replication of risk SNPs

Background: Functional single nucleotide polymorphisms (SNPs) are relevant to individual therapeutic approaches and may play a role in disease susceptibility. Genome-wide scans, which are now widely applied to detect disease-associated SNPs, provide only limited evidence about SNP associations. Their usefulness as disease markers requires appropriate phenotype analysis and retesting of the gene providing SNP information. Larger data sets of thousands of samples are necessary to confirm the suggested SNPs.

Methods: We applied a newly established microarray-based technology that significantly accelerates and simplifies such studies. A tailor-made microarray surface chemistry, sample/probe immobilization and a primer extension reaction are central to the multi-individual array (MIA) platform, which simultaneously identifies the same variable nucleotide in thousands of samples. The set of SNPs to be typed for is highly flexible and can be adapted to the demands of defined clinical questions.

Results: A MIA-SNP analysis of functional SNPs in the P2RX7 calcium channel is presented. One risk genotype has been verified by functional analysis using patch clamping. Two clinically relevant genotypes composed of 5 functional SNPs in the P2RX7 gene have been identified in patients with severe sepsis and septic shock, whereas no significant association has been found in patient suffering from hemophagocytic syndromes.

Conclusions: These results support a functional SNP genotyping of the P2RX7 gene in patients at risk of severe sepsis following surgical trauma.