Twin Study Finds Genetic Link for Fainting

Like many other medical conditions, fainting runs in families, a new study finds. The study included 51 sets of same-sex twins. At least 1 twin in each pair had fainted in the past. Fainting in both twins was twice as common among identical twins as among fraternal twins. Identical twins come from the same fertilized egg, which divides. All of their genes are the same. Fraternal twins come from two fertilized eggs. They have fewer genes in common. Other relatives of the twins in the study did not have an unusually high risk of fainting. Researchers said this suggests that fainting is not inherited through just one gene. The journal Neurology published the study online. HealthDay News wrote about it August 8.