Aim: To determine if there is an association between ABO variants or blood types and otitis media. Methods: DNA samples from 214 probands from Finnish families with recurrent acute (RAOM) and/or chronic otitis media with effusion (COME) were submitted for exome sequencing. Fisher exact tests were performed when (a) comparing frequencies of ABO genotypes in the Finnish probands with otitis media vs. counts in gnomAD Finnish, and (b) within the Finnish family cohort, comparing occurrence of RAOM vs. COME according to ABO genotype/haplotype and predicted blood type. Results: Female sex is protective against having both RAOM and COME. The wildtype genotype for the ABO c.260insG (p.Val87_Thr88fs*) variant resulting in blood type O was protective against RAOM. On the other hand, type A was associated with increased risk for COME. These findings remained significant after adjustment for age and sex. Conclusions: Within the Finnish family cohort, the wildtype genotype for the ABO c.260insG (p.Val87_Thr88fs*) variant and type O are protective against RAOM while type A increases risk for COME. This suggests that the association between the ABO locus and otitis media is specific to blood type, otitis media type and cohort.
Keywords: ABO; Finnish; blood type; exome sequencing; otitis media.