Caught in the Trio Trap? Potential Selection Bias Inherent to Association Studies Using Parent-Offspring Trios

The authors compared demographic & clinical characteristics of 122 singleton bipolar patients with those of 54 bipolar patients derived from parent-offspring trios. The singleton parents did not only present with a higher frequency of suicidal behaviour, but also a higher familial loading for suicidality. These findings suggest the genetic mechanism for disease might be different between trio-based & classic case control samples. Giving up case control designs for the sake of family-based association studies could be at the risk of selecting against several genetically determined factors. (19 refs.)