GJA5 and atrial fibrillation: However, we observed a significant difference (p = 0.03) when comparing Cx40 missense allele frequencies in our 34 lone AF tissues (average age at surgery 54 years), in which we detected a single nonsynonymous variant (variant:non-variant alleles = 1:67, 1.47%), and the frequency observed by Gollob et al. in 15 highly selected and young (average age of onset 45 years) lone AF tissue donors, in which four novel heterozygous Cx40 missense mutations were found (4:26, 13.3%) [9].