The father’s genotype would be Aa. As the mother is recessive, her genotype would be aa.
Below I have attached a Punnett square I made for the genotypes of the offspring. The possible phenotypes could be sneezing uncontrollably as a result to light exposure and also wincing / squinting at the sight of bright light. The percentage that the offspring would have ACHOO Syndrome is 50%, which means there is also a 50% chance they wouldn’t have ACHOO Syndrome. The phenotypes the children could also experience as a result of not having ACHOO Syndrome could involve not sneezing uncontrollably when around bright light, but I can imagine them squinting their eyes at light instead as that’s a natural thing people do, but they wouldn’t sneeze unlike those with ACHOO Syndrome.
