Schizophrenia and the serotonin-2A receptor promoter polymorphism

Serotonin-2A (5-HT2A) receptors have received much investigative attention in schizophrenia because (1) several studies have shown a decrease in the number of 5-HT2A receptors in the prefrontal cortex of postmortem brains of schizophrenic patients; (2) atypical antipsychotic drugs are antagonists for 5-HT2A receptors; and (3) a positive association between a T to C polymorphism at position 102 of the 5-HT2A receptor gene and schizophrenia has been reported. A G to A polymorphism at position -1438 of the 5-HT2A receptor gene was studied in 119 schizophrenic patients and 106 healthy control subjects, all of whom were Japanese. The genotype and allele frequencies did not differ between the patients and control subjects. Furthermore, the genotype frequency did not differ according to diagnostic subtype, family history, age at onset of illness, or daily dosage of antipsychotic medication. Our results suggest that the polymorphism does not contribute to the etiology or clinical characteristics of schizophrenia. However, the gene is greater than 20 kbp in length, and thus it is possible that other areas that affect expression of the gene may vary. We found that the -1438G/A variant was in linkage disequilibrium with the T102C polymorphism.