The role of genetic factors in the development of hemifacial spasm: preliminary results.

Hemifacial spasm (HFS) has been reported to result from vascular compression of the facial nerve at the root entry zone. The pathogenesis of HFS is not completely understood. Some study groups described that the vascular compression was due to the morphological changes of the vessel such as vertebral artery shifting. In this study, radiological evidence of VA shifting was identified in 26 (59.1%) of 44 patients with 3D-TOF MRA. We hypothesized that a genetic factor might be present for vascular change and tried to find out the role of a genetic factor more susceptible to vascular change causing vascular compression. We examined a single nucleotide polymorphism (SNP) in the genes related to vascular change such as methylenetetrahydrofolate reductase (MTHFR), thymidylate synthase enhancer region (TSER), endothelial nitric oxide synthase (eNOS), and vascular endothelial growth factor (VEGF) polymorphisms. 43 HFS patients and 207 healthy controls were genotyped and fasting plasma homocysteine (pHcy) concentrations were measured. The SNPs were genotyped using polymerase chain reaction (PCR) amplification followed by digestion with the restriction enzyme. The pHcy levels were not significantly different between HFS patients and controls. No association was detected between the SNPs in the selected genes and susceptibility to HFS. However, further study will be needed to confirm these findings.