ABSTRACT
<p><b>OBJECTIVE</b>To investigate the distribution of genotype and allele frequencies of the dopamine D4 receptor(DRD4) gene exon 3 48 bp variable number of tandem repeats polymorphism in Hunan Han population.</p><p><b>METHODS</b>The genotype and alleles of 304 healthy persons were examined with polymerase chain reaction, denaturing polyacrylamide gel electrophoresis and silver staining.</p><p><b>RESULTS</b>Seven alleles and twelve genotypes were found. The most common allele was allele 5 with a frequency of 70.6%. There was statistically significant difference in allele distribution between the Hunan Han population and the Han population of other regions such as Shanghai, Beijing and Sichuan in China (P< 0.05). Different allele frequency distributions were observed when compared to other ethnic populations such as Japanese, American, Mexican, and Italian (P< 0.05).</p><p><b>CONCLUSION</b>The distributions of allele of DRD4 gene exhibit regional and ethnic heterogeneity.</p>