CHRNA7 and Norrie disease: rs7178176 was previously reported in association with an increasing probability of dizziness at first smoke inhalation by adolescents in a Canada sample with a mixed ethnical origins.61 For the first time, we provide evidence that an epistatic effect of CHRNA7 is implicated in ND, which is in accord with the biological fact that (α7)5 forms a homomeric pentamer in humans.