[The development of functional gastrointestinal diseases: Genetic aspects].

Motility disorders of the upper and lower gastrointestinal tract encompass a very wide range of structurally different diseases. Functional dyspepsia and irritable bowel syndrome (IBS) are the most common functional gastrointestinal disorders in clinical practice. In spite of the considerable prevalence of these functional diseases, the knowledge of their development mechanisms is very scarce. Recent investigations of the impact of the motor and sensory components of the pathogenesis of these diseases have demonstrated that the development of IBS is associated with serotonin transporter gene (5-HTTLPR) impairment and that the patients with IBS show the inadequate response to nonselective cannabinoid receptor agonists, which is caused by cannabinoid receptor gene (CNR1) polymorphism. Most investigations (mainly trials with small sample sizes) dealing with the identification of pharmacogenetic features have indicated that there is a preponderance of patients with intermediary metabolism among those with functional gastrointestinal diseases. However, larger investigations are necessary for a more exact understanding of this aspect.