AIM:To study the correlation between genetic polymorphismof cytochrome P450IIE1 (CYPIIE1) and fatty liver.METHODS:Peripheral blood mononuclear cells werecollected in 56 patients with fatty liver,26 patients withoutfatty liver and 20 normal controls.Then PCR-RFLP was usedto analyze genetic polymorphism of CYPIIE1 in monocyteson the region of Pst Ⅰ and Rsa Ⅰ.RESULTS:The frequency of homozygotic C1 gene inpatients with alcoholic fatty liver (28.6 %),obese fatty liver(38.5 %),or diabetic fatty liver (33.3 %) was significantlylower than that of the corresponding patients without fattyliver (100 %,100 % and 80 % respectively),while thefrequency of C2 genes,including C1/C2 and C2/C2,wassignificantly higher (71.4 %/0 %,61.5 %/0 %,and 66.7 %/20 %) (P<0.01).The frequency distribution of the abovegenes of non-fatty liver patients (100 %/0,100 %/0,and80 %/20 %) was not significantly different from that of thenormal controls (85 %/15 %) (P>0.05).CONCLUSION:The genetic polymorphism of CYPIIE1 onthe position of Pst Ⅰ and Rsa Ⅰ is related to the susceptibilityof fatty liver.Besides,C2 gene may play a key role in thepathogenesis of fatty liver. AIM: To study the correlation between genetic polymorphism of cytochrome P450IIE1 (CYPIIE1) and fatty liver. METHODS: Peripheral blood mononuclear cells were collected in 56 patients with fatty liver, 26 patients without liver and 20 normal controls. PCR-RFLP was used to analyze genetic polymorphism of CYPIIE1 in monocyteson the region of Pst I and Rsa I .RESULTS: The frequency of homozygotic C1 gene in patients with alcoholic fatty liver (28.6%), obese fatty liver (38.5%), or diabetic fatty liver (33.3%) was significantlylower than that of the corresponding patients without fattyliver (100%, 100% and 80% respectively), while the frequency of C2 genes, including C1 / C2 and C2 / C2, wassignificantly higher (71.4% / 0%, 61.5% / 0%, and 66.7% / 20%) (P <0.01). The frequency distribution of the above genses of non-fatty liver patients (100% / 0,100% / 0, and80% / 20%) was not significantly different from that of normal controls % / 15%) (P> 0.05) .CONCLUSION: The genetic polymorphism of CYPIIE1 on the position of Pst I and Rsa I is related to the susceptibility of fatty liver. Besides, C2 gene may play a key role in the pathogenesis of fatty liver.