Novel connexin40 missense mutations in patients with familial atrial fibrillation

This research was aimed at screening connexin40, a cardiac gap junction protein alpha 5, for genetic defects in patients with familial atrial fibrillation (AF). The subjects included 218 unrelated families with lone AF and 200 ethnically matched unrelated healthy individuals as controls. The entire coding region of the connexin40 gene was sequenced initially in 218 unrelated probands with familial AF. The relatives of mutation carriers and 200 controls were subsequently genotyped for the presence of mutations identified in probands. Three novel connexin40 mutations, p.V85I, p.L221I, and p.L229M, were identified in 3 of 218 unrelated AF families, respectively. These heterozygous missense mutations co-segregated with AF in the families and were absent in the 200 unrelated control subjects. A cross-species alignment of connexin40 protein sequences revealed that the altered amino acids were completely conserved evolutionarily. The findings expand the spectrum of mutations in connexin40 linked to AF and provide new insight into the molecular aetiology involved in the pathogenesis of AF.