The reviewed research on the CHRNA5-CHRNA3-CHRNB4 gene cluster in smoking cessation phenotypes from animal and human genetic data suggests that variability in these subunit genes may have some small contribution to the physical withdrawal symptoms and the ability to abstain from smoking. The role of variation in the CHRNA5-CHRNA3-CHRNB4 gene cluster may be important in determining response to treatments for smoking cessation; however, this hypothesis has not been tested extensively. Ethnicity and smoking behavior phenotypes may be critical factors in determining the significance of associations between this gene cluster and smoking cessation and cessation treatment response.
