Family-based association analysis of serotonin genes in pathological gambling disorder: evidence of vulnerability risk in the 5HT-2A receptor gene.

Pathological gambling (PG) has become a growing public health problem in many countries around the world. PG is an impulse control disorder and its behavior and psychopathology present similarities with substance abuse disorders. Evidence from twin studies supports a significant genetic predisposition to PG, but the precise genetic loci still remain unclear. The present study investigates the allele and genotype distribution of polymorphisms of the serotonin transporter, serotonin receptor 1B and 2A genes in 140 sib-pairs discordant for the diagnosis of PG. A significant association of the C/C genotype of the serotonin receptor 2A T102C (rs 6313) polymorphism and the PG phenotype was observed [OR = 1.7 (1.1-3.4)]. This preliminary result is consistent with the hypothesis that the serotonin system is associated with addiction behavior and similar results have been reported for nicotine and alcohol dependence.