The exact cause of geographic tongue has not been identified. However, because the condition may be present in several members of the same family, genetics may increase a persons chances of developing the condition. A study by Guimares (2007) showed that a specific variant of a gene called IL-1B (interleukin-1 beta) is associated with an increased risk of developing geographic tongue and suggests a genetic basis for the development of the disease. Further research may result in a better understanding of the genetic influences involved in the development of geographic tongue. 
What causes Geographic tongue ?