Pain and genes: Genetic contribution to pain variability, chronic pain and analgesic responses

Pain afflicts up to 20% of the population in the Western World and represents a challenge for clinicians and scientists because of a large interindividual variability in: (a) pain sensitivity, (b) in development of chronic pain and (c) in the response to analgesics. The personal and socioeconomic costs are considerable. The genetic approach to investigate pain has identified several potential areas of interest to understand genetic predisposition, the occurrence of pain and the variability of pain in human and in mice. In this paper, we will focus on genetic methods and variables influencing pain and pharmacotherapy elucidating the complexity of the area. Examples of promising candidate genes and allelic variables have been intensively studied and the number has been increasing during recent years with more or less reproducible results.