"Observational study of gene-disease association. (HuGE Navigator); The frequency of haplotype LCT consisting of 3 function polymorphic sites dopamine D4 receptor(DRD4)-1240L/S -616C/G and -521C/T in primary nocturnal enuresis patients was statistically higher than that in healthy controls (x2=5.88 P<0.05)."xsd:string