Association of a polymorphism in the NRXN3 gene with the degree of smoking in schizophrenia: a preliminary study.

Whole genome scan studies have recently identified the NRXN1 and NRXN3 genes as potential contributing factors in the risk for nicotine addiction. We have genotyped 15 single nucleotide polymorphisms (SNPs) spanning the NRXN1 and NRXN3 genes in 195 unrelated patients with schizophrenia for whom information about their smoking status and number of cigarettes smoked per day (CPD) was obtained. The NRXN3 marker rs1004212 was significantly associated with quantity of tobacco smoked.