Genetic Markers in Psychiatric Genetics

Are the strategies for the identification of susceptibility genes in psychiatric diseases the same as those that have been used to successfully identify genes in monogenic diseases? How many cases, families, and markers are needed? These methodological questions are still a matter of debate for all complex traits, including psychiatric diseases. Furthermore, new technologies and methodologies for studying human genetics are emerging, and current protocols may rapidly become obsolete. This chapter presents an overview of the classical and novel gene identification strategies in complex diseases, and focuses on the problems encountered in psychiatric diseases. For each method, we discuss their relevance and what will probably be available in the near future. This review is written for clinicians close to the patients and molecular biologists close to the genes, who are not always familiar with the methods used to detect the link between individual genetic variations and the susceptibility to psychiatric diseases.