Several studies suggest that the CC genotype at the single nucleotide polymorphism (SNP) rs12252 of IFITM3 confers a genetic predisposition to pandemic influenza A in Europeans and Han Chinese, although one study in a British cohort failed to show an association.
The IFITM3 rs12252 variant was associated with respiratory infection hospitalization but not specifically in patients infected with Influenza A(H1N1)pdm09.