The three different level of endophenotype studies, including the endophenotype, the genetic risk factors and the disease phenotype. A thorough study into the relationship of the individual elements may produce a complicated network as in the study of Cruchaga and colleagues. Not all variants associated with the disease phenotype will eventually become risk genes for the disease in question. This raises the questions whether the elements of the phenotype represented by the endophenotype are sufficiently disease-specific.
Child Neurology Fellow and epilepsy genetics researcher at the Children’s Hospital of Philadelphia (CHOP), USA and Department of Neuropediatrics, Kiel, Germany