RESUMEN
<p><b>OBJECTIVE</b>To investigate the association of estrogen receptor (ER) gene polymorphism and primary trigeminal neuralgia.</p><p><b>METHODS</b>By polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), ER gene polymorphism was analyzed in 20 trigeminal neuralgia (TR) patients and 20 control individuals, and the distribution of ER genotype was compared in TR group and control group.</p><p><b>RESULTS</b>There was no significant difference in frequencies of allele and genotype in XbaI or PvuII polymorphism or XbaI with PvuII polymorphisms together between TR group and control group (P > 0.05). The genotypic distribution of Xx or PpXx in TR group was higher than control group, and it was contary to xx, ppxx or Ppxx in TR group and control group.</p><p><b>CONCLUSION</b>XbaI or PvuII polymorphism may be related to TR. Women with PpXx genotype may be a dangerous factor to primary trigeminal neuralgia.</p>