河南地区汉族人群复发性流产患者HLA-DRB1、DQB1等位基因多态性的研究

目的探讨复发性流产易感性与人类白细胞抗原(HLA)DR、DQ区域基因多态性的关系。方法采用序列特异性引物聚合酶链反应(PCR-SSP),分析200例复发性流产患者(患者组)和200例无不良妊娠史正常妇女(对照组)的DRB1和DQB1基因型。结果患者组中的DQB1*03(39.25%)等位基因频率显著高于对照组(32.5%)(P=0.047<0.05,RR=1.208),DQB1*05(14%)等位基因频率较对照组显著降低(22.75%)(P=0.001<0.05,RR=0.615);患者组中DRB1*09(14%)等位基因频率显著高于对照组(9.25%)(P=0.036<0.05,RR=1.514),DRB1*12(8.5%)等位基因频率较对照组显著降低(14%)(P=0.014<0.05,RR=0.607)。结论河南地区汉族人群中DQB1*03、DRB1*09可能是复发性流产的易感基因,而DQB1*05、DRB1*12可能对复发性流产的发生有保护作用。     

人白细胞抗原(HLA)-DRB1 *0901、1501和HLA-DQB1 *0301、0602与新疆哈萨克族食管鳞状细胞癌相关性

目的 从基因水平探讨新疆哈萨克族食管鳞状细胞癌HLA-DRB1和DQB1等位基因的遗传易感性,为寻找哈萨克族食管鳞状细胞癌的易感基因提供线索.方法 运用序列特异性引物聚合酶链反应(PCR-SSP)技术,检测新疆哈萨克族食管鳞状细胞癌200例、正常食管黏膜177例HLA-DRB1 *0901、1501和DQB1 *0301、0602等位基因的分布.结果 新疆哈萨克族食管鳞状细胞癌患者HLA-DRB1 *1501、DQB1 *0301和DQB1 *0602基因分布频率(0.455,0.760和0.690)明显高于177例正常食管黏膜上述等位基因分布频率(0.232,0.520,0.554),差异具有统计学意义(OR=2.78,2.93,1.80;P值均<0.05);新疆哈萨克族食管鳞状细胞癌HLA-DRB1 *0901等位基因分布频率(0.105)与哈萨克族正常食管黏膜(0.102)对比,差异无统计学意义(OR=11036,P>0.05);HLA-DQB1 *0602等位基因的分布频率在哈萨克族中低分化鳞状细胞癌组中的分布频率(0.742)高于高分化鳞状细胞癌组(0.597),差异具有统计学意义(P<0.05).结论 HLA-DRB1 *1501、DQB1 *0301和DQB1 *0602可能是哈萨克族食管鳞状细胞癌的易感基因,HLA-DQB1 *0602与哈萨克族食管鳞状细胞癌的分化程度有关.     

HLA-DRB1、DQB1基因与汉族人群寻常型天疱疮的相关性研究

目的　探讨 HL A- DRB1、DQB1位点基因在汉族人群寻常型天疱疮易感性中的作用。方法用序列特异性引物 -聚合酶链反应方法 ,对 6 1例寻常型天疱疮 (pemphigus vulgaris,PV)患者和 5 7名正常对照进行了 HL A- DRB1、DQB1等位基因的分型 ,并分析了 DRB1、DQB1基因在两组中的分布。结果　与正常对照组比较 ,PV组 DR4、DRB1* 14 (* 14 0 1、* 14 0 4、* 14 0 5 )基因频率明显增高 (Pc分别 <0 .0 5及P<0 .0 1) ,差异有显著性 ;PV组 DQB1* 0 5 0 3、DQB1* 0 30 2基因频率明显增高 (Pc均 <0 .0 5 ) ,差异有显著性。对 DR4阳性样本的组内基因亚型分型结果发现 ,PV组中 DRB1* 0 4 0 3、DRB1* 0 4 0 6频率显著增高(Pc<0 .0 5 ) ,差异有显著性。 PV患者组单倍型 HL A- DRB1* 0 4 ,DQB1* 0 30 2和 HL A- DRB1* 14 ,DQB1* 0 5 0 3频率明显增高 (P<0 .0 5 )。结论　HL A- DRB1* 0 4 ,DQB1* 0 30 2和 HL A- DRB1* 14 ,DQB1* 0 5 0 3可能是汉族人 PV推测的易感单倍型。     

人类白细胞Ⅱ类抗原DR、DQ基因型与妊娠期糖尿病的相关性研究

目的探讨人类白细胞II类抗原DR、DQ基因型与妊娠期糖尿病的相关性。方法对26例GDM孕妇及同期入院的42例正常健康孕妇,采用序列特异性引物聚合酶链反应技术(PCR-SSP)检测HLA-II类抗原DR和DQ的等位基因。结果研究中发现,DQA1*0101、DQA1*0201、DQB1*0609、DRB l*07-DQA1*0201-DQB1*0201基因频率在GDM中显著高于正常对照组,两组比较,统计学有差异(Ρ<0.05)。DQB1*0301基因频率在GDM中显著低于正常对照组,两组比较,有统计学差异(Ρ<0.05)。结论人类白细胞II类抗原DR、DQ基因型与GDM的易感性和保护性存在关联。DQA1*0101、DQA1*0201、DQB1*0609、DRB l*07-DQA1*0201-DQB1*0201基因是GDM的易感基因。DQB1*0301基因是GDM的保护基因。     

HLA-DQ多态性基因与系统性红斑狼疮易感性

采用PCR-SSO方法对江苏籍汉族SLE患者和正常对照组HLA-DQ作基因分型.结果显示,患者组中DQA1*0102频率(RR=3.43.Pc=0.03164)及HLA-DQA1*0102,DQB1*0601和HLA-DQA1*0102,DQB1*0602单倍型频率(RR=9.4,P=0.027和RR=12.4.P=0.007)均明显高于正常对照组.相反,DQA1*0601频率则显著低于正常对照组(RR=0.29,Pc=0.0461).但没发现任何DQB1等位基因与SLE有关.这提示在汉族SLE与HLA-DQ基因的相关性方面,DQA1*0102起主导作用.DQA1*0102或某个与其紧密连锁的其它基因可能是汉族SLE的易感基因,而DQA1*0601则可能对SLE的发病有一定的保护性.     

用核酸序列测定1型糖尿病HLA-DPB1和DQB1第2外显子基因

目的 研究山东省汉族1型糖尿病与HLA－DPB1和HLA－DQB1等位基因的相关性。方法 采用基于核酸序列测定的基因分型技术对52例1型糖尿病患者及38例正常对照进行了DPB1和DQB1基因分析。结果 DPB1＊2201（P＜0．01）和DQB1＊0201（P＜0．01）、＊0303（P＜0．05）及＊0604（P＜0．05）等位基因频率在糖尿病患者组显著高于对照组,而PB1＊0402（P＜0．01）和DQB1＊0301（P＜0．01）等位基因在糖尿病患者组显著低于对照组。结论 DPB1＊2201和DQB1＊0201、＊0303及＊0604等位基因可能是山东省汉族1型糖尿病的易感性等位基因,而DPB1＊0402和DQB1＊0301等位基因可能是山东省汉族1型糖尿病的保护性等位基因。     

中国天疱疮患者的免疫遗传易感性研究

目的探讨中国天疱疮患者的免疫易感基因位点.方法本实验应用序列特异性引物聚合酶链式反应(SSP-PCR)技术对HLA-II类等位基因进行特异性体外扩增,分析了天疱疮患者HLA基因的DR位点和DRB1、DQB1多态性,并将天疱疮患者的基因频率与正常人结果进行χ2检验,以探讨中国天疱疮易感性基因位点.结果天疱疮患者中DR4的频率为93.3%(28/30),DR14的频率为63.3%(19/30),天疱疮患者中的DRB1*04和DRB1*14的频率分别为40%(12/30)和53.3%(16/30),经χ2分析,与正常对照组相比具有显著的差异性;在28个DR4+的天疱疮患者中有13个DRB1*0402,在19个DR14+天疱疮患者中DRB1*1401频率显著增高(P<0.01).所有DRB1*04+患者均为DQB1*0302,所有DRB1*14患者均为DQB1*0503.结论中国人天疱疮易感性与HLA的DR4、DR14抗原以及DRB1*04、DRB1*14、DRB1*0402、DRB1*1401基因位点与高度相关.     

云南汉族系统性红斑狼疮的易感及抵抗单体型研究

目的：探讨云南汉族系统性红斑狼疮（SLE）在HLA－DRB1、DQA1、DQB1等座位的易感抵抗单体型,方法：采用多聚酶链反应－序列特异性引物（PCR－SSP）技术对63例动态汉族SLE患者及54名同民族健康对照进行DRB1、DQA1、DQB1基因分型。结果：与正常对照组比较,SLE病人中有5个单体型频率显著升高;11个单体型频率在病例组中明显降低。结论：云南汉族SLE的易感单体型为DQA1^*0102-DQB1^*0601,DR15-DQA1^*0102-DQB1^*0601,DR15-DQA1^*0102-DQB1^*0602,DR15-DQA1^*0101-DQB1^*0601,DR15-DQA1^*0103-DQB1^*0601;其余均为低抗单体型。     

AITDs与HLA等位基因DQA1*0301、DR9的相关性研究

目的：探讨山东沿海地区自身免疫性甲状腺病（AITDs)与HLA－DQA1＊301，DR9的相关性。方法：采用多聚酶链式反应序列特异物分析（PCR－SSP）技术，扩增HLA等位基因DQA1＊0301，DR9的目的DNA片段（分别为199，236 bP)，分析2对等位基因在不同人群中表面频率的差异（χ^2检验），结果：山东沿海地区GD和HT女性患者组DQA1＊0301等位基因频率均显著高于对照组（分别为P＜0．001，OR＝4．89，P＜0．01，OR＝4．95）；DR9等位基因频率仅HT女性组显著高于对照女性组（P＜0．05，OR＝3．90），DQA1＊0301／DR9共同表达的频率，GD和HT女性组较对照女性组均显著性增高（分别为P＜0．05，P＜0．01），GD组和HT组2组间均无显著性差异（P＞0．05），结论：HLA－DQA1＊0301等位基因是山东沿海地区女性GD患者的易感基因；DQA1＊0301，DR9等位基因均是该地区女性HT患者的易感基因，2对等位基因在男性AITDs患者中的分布情况尚待进一步观察。     

昆明彝族人群HLA-DRB1、DQB1基因多态性

目的　调查昆明彝族 HL A- DRB1、DQB1基因的多态性。方法　应用聚合酶链反应 -序列特异性引物基因分型技术 ,对昆明地区 70名彝族健康儿童进行了 HL A- DRB1、DQB1位点的基因分型。结果在 HL A- DRB1位点共检出了 12种等位基因 ,其中等位基因频率大于 10 %的依次为 HL A- DRB1* 12 (33.5 7% )、DRB1* 0 90 1(11.4 3% )、DRB1* 0 4 (11.4 3% ) ,等位基因频率大于 5 %而小于 10 %的依次为 DRB1* 0 1(8.5 7% )、DRB1* 11(7.86 % )、DRB1* 14 (7.14 % )、DRB1* 15 (7.14 % )、DRB1* 0 8(5 % ) ,等位基因频率小于 5 %依次为 HL A- DRB1* 0 3(2 .86 % )、DRB1* 13(2 .14 % )、DRB1* 0 7(1.4 3% )、DRB1* 16 (1.4 3% )。在 HL A- DQB1位点共检出了 7种等位基因 ,其中等位基因频率大于 10 %的依次为 HL A- DQB1*0 30 1(45 % )、DQB1* 0 5 (2 2 .14 % )、DQB1* 0 30 3(12 .14 % ) ,等位基因频率大于 5 %而小于 10 %的依次为DQB1* 0 4 (6 .4 3% )、DQB1* 0 6 (6 .4 3% ) ,等位基因频率小于 5 %的依次为 DQB1* 0 2 0 1(4.2 9% )、DQB1* 0 30 2 (3.5 7% )。结论　昆明彝族 HL A基因多态性分布不同于北方汉族人群 ,也不同于南方汉族人群 ,有其独特性。     

Novel HLA-DR2-related haplotypes in Hong Kong Chinese implicate the DQB1*0602 allele in susceptibility to multiple sclerosis.

Multiple sclerosis (MS) is strongly associated with the HLA-Dw2 haplotype DRw15.DQw6 in Caucasoids, although the relative contributions of DR and DQ loci to disease susceptibility are unknown. The situation is further complicated by the apparent lack of an association between DR2 and MS in Orientals. This study examined 42 DR2-positive chromosomes in healthy Chinese and 12 DR2-positive chromosomes in MS patients from Hong Kong, using oligonucleotide hybridizations of DQA1, DQB1, DRB1, and DRB5 polymerase chain reaction (PCR) products. There was marked heterogeneity in DR2-related haplotypes in controls (ten types), where the most frequent haplotype, confirmed in one family, involved the novel arrangement DRB1*1501, DQB1*0601. Another common haplotype had the unusual combination of DRB1*1602, DRB5*0101 as confirmed by DNA sequencing of the DRB5 allele. In contrast, the most common DR2-related haplotype in MS patients was the 'classical' Dw2 haplotype DRB1*1501, DQB1*0602, with a frequency of 50% compared with 12% in controls (P = 0.01). Novel DR,DQ linkage disequilibrium relationship in Hong Kong Chinese have permitted recognition of DQB1*0602 as a susceptibility allele in DR2-positive MS patients, although a role for the DRB1*1501 allele in MS pathogenesis has not been excluded by this study.     

HLA—DR,DQ基因多态性与系统性红斑狼疮相关性的研究

应用聚合酶链反应结合顺序特异的寡核苷酸探针杂交（ＰＣＲ／ＳＳＯＰＨ）方法对江苏籍汉族ＳＬＥ患者和健康对照组ＨＬＡ－ＤＲＢ１、ＤＱＡ１：ＤＱＢ１基因作寡核苷酸分型。结果发现患者组中ＤＲＢ１＊１５０１、ＤＱＡ１＊０１０２等位基因频率及ＨＬＡ－ＤＲＢ１＊１５０１、－ＤＱＡ１＊０１０２、－ＤＱＢ１＊０６０２单倍型频率均明显高于正常对照组；相反，ＤＲＢ１＊０４（ＤＲ４）、ＤＱＡ１＊０６０１频率则明显低于正常对照组。所有ＤＱＢ１等位基因频率在两组间无显著差异，而ＤＱＡ１＊０１０２仅存在于ＤＲ２阳性的个体之中，推测汉族ＳＬＥ的易感基因可能靠近ＤＲ位点，且与单倍型ＨＬＡ－ＤＲＢ１＊１５０１、－ＤＱＡ１＊０１０２、－ＤＱＢ１＊０６０２紧密连锁，该单倍型可作为汉族ＳＬＥ易感的遗传标记。相反ＤＲ４，ＤＱＡ１＊０６０１则对ＳＬＥ发病可能有一定的保护性。     

DQB1*0602 confers genetic susceptibility to multiple sclerosis in Afro-Brazilians

We studied the distribution of the HLA-DRB1, -DQA1 and -DQB1 alleles in 44 Afro-Brazilian patients with multiple sclerosis and 88 controls. Although no significant differences were found between the patients and controls for the DRB1 and DQA1 alleles, the HLA-DQB1*0602 allele was positively associated with multiple sclerosis (45.0% vs. 17.0%, Pc=0.024, RR=3.31). The positive extended haplotypes for DQB1*0602 were more frequent in patients than controls, although the differences were not statistically significant in any of them. These results in Afro-Brazilians are in line with other studies which have found DQB1*0602 to be associated with the disease in the absence of the DRB1*1501 allele. We therefore think that the association with the disease in this ethnic group is more allelic than haplotypic.     

The HLA-DQ(α1*0102, β1*0602) heterodimer may confer susceptibility to multiple sclerosis in the absence of the HLA-DR(α1*01, β1*1501) heterodimer

The frequencies of DR2, DQ6-related DRB1, DQA1, DQB1 haplotypes were compared in 181 multiple sclerosis patients and 294 controls in Norway. All individuals carried either DR2 or DQ6, i.e., the DQ(α1*0102, β1*0602) heterodimer. The DR(α1*01,β1*1501) and the DQ(α1*O102,β1*O602) heterodimers were carried by 171 of the patients (94%) and 289 (98%) of the controls. Seven of the patients and one of the controls carried the DQ(α1*0102, β1*0603) heterodimer together with the DR(α1*01, β1* 1501) heterodimer. Two patients carried the DQ(α1*0102, β1*O602) heterodimer in the absence of the DR(α1*O1, β1*1501) heterodimer. The DR(α1*01, β1*1501) heterodimer was not observed in the absence of the DQ(α1*0102, β1*O602) heterodimer or the DQ(α1*O102, β1*0603) heterodimer, neither in the patients nor in therols. Our findings indicate that the genes encoding the DQ(α1*0102,β1*0602) heterodimer may confer susceptibility to developing multiple sclerosis in the absence of the DRB 1* 1501 allele.     

HLA-DQA1 and HLA-DQB1 genes may jointly determine susceptibility to develop multiple sclerosis

Serologic DR typing and genomic DRB1, DQA1, DQB1, DPA1, and DPB1 typing using sequence-specific oligonucleotides were performed in 69 multiple sclerosis (MS) patients and 181 healthy controls on in vitro amplified DNA. The frequencies of DR2 as well as the DR2-associated DQA1*0102 and DQB1*0602 alleles were increased whereas DR7 was decreased among MS patients. The distribution of DR4 subtypes as well as DP alleles were similar in patients and healthy controls. All but one of 23 DR4-positive MS patients carried the DQB1*0302 allele, whereas five of five DR7-positive MS patients carried the DQB1*0303 allele. Of the MS patients, 99% compared to 79% of the controls carried DQA1 alleles encoding glutamine at residue 34, while 97% of the MS patients compared to 72% of the controls carried DQB1 alleles encoding DQ beta chains sharing long polymorphic stretches. A combination of such DQA1 and DQB1 alleles was carried by 96% of the MS patients and 60% of the controls, suggesting an association between MS and a combination of particular DQA1 alleles and DQB1 alleles. The corresponding DQ alpha beta heterodimers may have in common an ability to bind a particular peptide.     

HLA class II (DRB1, DQA1 and DQB1) associated genetic susceptibility in Iranian multiple sclerosis (MS) patients

The association of HLA class II alleles with multiple sclerosis (MS) has been amply documented. In the present study, the role of HLA class II (DRB1, DQA1 and DQB1) alleles and haplotypes was investigated in 43 unrelated Iranian chronic progressive multiple sclerosis (CP-MS) patients compared with 100 healthy individuals. HLA typing for DRB1, DQA1 and DQB1 was performed by restriction fragment length polymorphism (RFLP). Subtypes of DR4, DR15 and DR16 were defined using polymerase chain reaction (PCR) amplification with sequence-specific primers (PCR-SSP). The results show that, among DR2-positive MS patients and the control group, a positive association with the DRB1*1503, DQA1*0102, DQB1*0602 haplotype (21% vs. 2.7%, P=0.057, RR=9.8) and a negative association with the most frequent DR15 haplotype in the control group, DRB1*15021, DQA1*0103, DQB1*0601 (7% vs. 24.3%, P=0.001), were observed. No significant association was found with the analysed HLA-DRB1, DQA1 and DQB1 alleles.     

Association of HLA-DR and -DQ genes with narcolepsy in Koreans: comparison with two control groups, randomly selected subjects and DRB1*1501-DQB1*0602--positive subjects

The purpose of this study was to investigate the association of human leukocyte antigen (HLA) class II alleles with narcolepsy-cataplexy susceptibility in Koreans. The distribution of HLA-DRB1 and -DQB1 alleles and presence or absence of DRB3/4/5 alleles were examined in 60 narcoleptic patients with clear-cut cataplexy, and the results were compared with two groups of healthy controls: 200 randomly selected controls and 144 DRB1*1501-DQB1*0602 positive controls. All of the narcoleptic patients were DRB1*1501 and DQB1*0602 positive, and their frequencies were significantly higher in patients than in random controls (100% vs 17.0%, p(c) = 2.3 x 10(-30), OR = 583.96; 100% vs 16.5%, p(c) = 3.9 x 10(-31), OR = 605.00). The HLA association in Koreans was as tight as that reported in Japanese. Several DRB1 (*0101, *0405, *0901) and DQB1 alleles (*0303, *0401, *0501, *0601, *0604) were found to have weak protective effects against narcolepsy. DRB4 showed strong protective effect, and this was also significant when compared with DRB1*1501-DQB1*0602 positive controls (18.3% vs 44.4%, p(c) = 0.001, OR = 0.28). DRB3 (OR = 1.86) and DQB1*0301 (OR = 2.45) were found to have weak predisposing effect, when compared with DRB1*1501-DQB1*0602 positive controls. The protective effect of DRB4 has to be further studied in other populations.     

HLA-DRB1, -DQA1, -DQB1 and DPB1 susceptibility alleles in Cameroonian type 1 diabetes patients and controls.

It is known that certain combinations of alleles within the human leucocyte antigen (HLA) complex are associated with susceptibility or resistance to type 1 diabetes. Variable associations of DR and DQ with type 1 diabetes are documented in Caucasians but rarely in African populations; however, the role of HLA-DP genes in type 1 diabetes remains uncertain. In order to investigate the HLA class II associations with type 1 diabetes in Cameroonians, we used sequence-specific oligonucleotide probing (SSOP) to identify DRB1, DQA1, DQB1 and DPB1 alleles in 10 unrelated C-peptide negative patients with type 1 diabetes and 90 controls from a homogeneous population of rural Cameroon. We found a significantly higher frequency of the alleles DRB1*03 (chi2 = 17.9; P = 0.001), DRB1*1301 (chi2 = 37.4; P < 0.0001), DQA1*0301 (chi2 = 18.5; P = 0.001) and DQB1*0201 (chi2 = 37.4; P < 0.001) in diabetes patients compared to the control group. The most frequent alleles in the control population were DQA1*01, DQB1*0602 and DRB1*15. The DRB1*04 allele was not significantly associated with type I diabetes in our study population. We observed no significant difference between patients and controls in DPB1 allele frequency. In conclusion, the data in Cameroonian diabetes patients suggest the existence of HLA class II predisposing and specific protective markers, but do not support previous reports of a primary association between HLA-DP polymorphism and development of type I diabetes.     

Distribution of HLA-DQA1, -DQB1 and DRB1 alleles in black IDDM patients and controls from Zimbabwe

We have used the XI Histocompatibility Workshop sequence-specific oligonucleotide probes to determine the DRB1, DQA1 and DQB1 genotypes by dot-blot hybridization of polymerase chain reaction (pcr)-amplified material from a homogenous black population in Zimbabwe. The DR4 subtype DRB1*0405, the DR3 subtype DRB1*0301, DQB1*0201 and DQB1*0302 and DQA1*0301 and DQA1*0501 were significantly increased in the IDDM group compared to the controls, whereas DRB1*11, DQB1*0602 and DQA1*0102 were significantly decreased. Taken together, the data show that susceptibility and resistance to IDDM are associated both with particular haplotypes and DQA1-DQB1 heterodimers without one or other being overriding.     

Combinations of HLA DR and DQ molecules determine the susceptibility to insulin-dependent diabetes mellitus in Koreans

The association of HLA-DRB1 and DQB1 genes with IDDM in Koreans was assessed using 115 IDDM patients and 140 nondiabetic controls. DQB1*0201 is the only DQB1 allele positively associated with IDDM while DQB1*0602, *0601 and *0301 are negatively associated. Three DRB1 alleles (DRB1*0301, DRB1*0407 and DRB1*0901) are positively associated while four DR allele groups (DRB1*15, DRB1*12, DRB1*10 and DRB1*14) are negatively associated. However, Haplotype analyses indicated that DQB1*0302, DRB1*0405 and DRB1*0401 may confer susceptibility because the DRB1*0405-DQB1*0302 and DRB1*0401-DQB1*0302 haplotypes are positively associated with the disease. The lack of association in Koreans with the DQB1*0302 allele, which appears predisposing in studies of non-Orientals, is due to its strong linkage disequilibrium (LD) with the protective DRB1*0403 and *0406 alleles, while the lack of association with DRB1*0405 is because of its strong LD with the protective DQB1*0401 allele. Nine DR/DQ genotypes confer significantly increased risk to IDDM. Seven of the nine genotypes (DR3/4s, DR1/4s, DR4s/13, DR4s/8, DR4s/7, DR9/13 and DR3/9) were also found to be at high risk to IDDM in other populations, while the two others (DR1/9 and DR9/9) are only found in Koreans. Surprisingly, DR4/4 homozygotes are not associated with high risk to IDDM in Koreans. This observation can be explained by the high frequency of protective DR4 subtypes and the protective DQ alleles (0301 and 0401) associated with the susceptible DR4 alleles. Our analyses indicate that the counterbalancing act between susceptible DRB1 and protective DQB1, and vice versa, that has already been observed in Chinese and Japanese, is the major factor responsible for the low incidence of diabetes in Koreans.