Genetic factors in severe cases of (H1N1) 2009 influenza

The pandemic influenza (H1N1) 2009 raised a number of issues, of which we address the following: Why did between 25 and 30% of severe influenza cases show no obvious risk factor? We hypothesize that an element that can contribute to the answer are host genetic risk factors involved in poor disease progression. Several indications led us to this hypothesis: i) studies of familial aggregation in Iceland and Utah Mormons show some heritability of influenza mortality; ii) nearly 300 known human genes are necessary for the replication of the influenza virus, and iii) the most severe cases of influenza A (H1N1) 2009 showed a deregulation of the adaptive immune system. We are addressing this problem through a case-control design (hospitalized cases of influenza (H1N1) 2009 confirmed against outpatient cases, also confirmed for (H1N1) 2009), which will be genotyped for more than a million single nucleotide polymorphisms (SNPs) and copy number variations (CNVs).