Epidemiology/Health Services/Psychosocial Research ORIGINAL ARTICLE

Type 1 Diabetes Environmental Factors and Correspondence Analysis of HLA Class II Genes in the Yemenite Jewish Community in Israel

1 2 NAOMI WEINTROB, MD NATALI ABRAMOV, MA HLA-DQ and -DR in the HLA immune 2,3 1 ELLIOT SPRECHER, PHD AVIVA ARBEL, RD response region of the short arm of chro- 4 1 SHOSHANA ISRAEL, PHD ZEEV JOSEFSBERG, MD mosome 6 (3,4). The increasing interac- 1 4 ORIT PINHAS-HAMIEL, MD CHAIM BRAUTBAR, PHD 4 2, 3 tion of these susceptible genes with the OH JOONG KWON, PHD NINA ARDI MD 2 P V , environment, leading to autoimmune KONSTANTIN BLOCH, PHD ␤-cell destruction, may account for the steady rise in the frequency of type 1 dia- betes in the last decades (5). In particular, early exposure to cow’s milk has been OBJECTIVE — The Israeli Yemenite Jewish community has displayed an exceptionally rapid linked by many investigators to initiation increase in the frequency of type 1 diabetes, having the highest rate of all Israeli ethnic groups. of ␤-cell autoimmunity in individuals at We studied the role of the environment, in relation to the nature and frequency of HLA class II high genetic risk; however, the contribu- genes, to evaluate its possible involvement in the development of diabetes. tion of early exposure to the pathogenesis of type 1 diabetes is still controversial (6). RESEARCH DESIGN AND METHODS — We interviewed 196 elderly Yemenite Israel, too, has witnessed a general in- women, who had immigrated to Israel as adults, in programmed encounters about signs and crease in the incidence of type 1 diabetes symptoms of type 1 diabetes, infant feeding customs, and infectious diseases in Yemen. We also performed HLA oligotyping of DRB1, DQA1, and DQB1 genes in 120 unrelated Yemenite Jews, over the last 15 years. There is, however, a including 44 type 1 diabetic patients and 76 healthy control subjects, and used these data in notable variation among Israel’s different correspondence analysis comparing Yemenites with different Israeli ethnic groups. ethnic groups, which has been attributed to differences in genetic or environmental RESULTS — Interviews indicated that early exposure to cow’s milk was very common in factors (7). Among these groups, the Ye- Yemen. However, none of the women could recall classical presentations of diabetes. HLA menites are unique, having the highest in- oligotyping showed that gene frequencies of non-Asp-57 (of the HLA-DQB chain) in the patients cidence of type 1 diabetes (18.5/100,000) (0.94) and control subjects (0.6) were similar to those of other populations with a known high compared with the overall Jewish popu- incidence of type 1 diabetes. Correspondence analysis revealed that Yemenite Jews are geneti- lation (5.7/100,000) (8). cally distinct from other ethnic groups in Israel. The Yemenite Jews immigrated to Is- CONCLUSIONS — The genetic distinctiveness of Yemenite Jews may explain their unusu- rael en masse between 1948 and 1951 ally high incidence of type 1 diabetes in Israel. Despite the presence of highly susceptible from a distant Moslem country that was diabetogenic HLA class II genes in this community, early exposure to cow’s milk did not cause not only underdeveloped but also volun- phenotypic expression of diabetes in Yemen. This finding suggests that in this population, either tarily isolated from the rest of the world cow’s milk does not play a crucial role in triggering diabetes, or environmentally conferred (9). Yemen’s Jews were doubly isolated— protection, such as frequent infectious disease in Yemen, was dominant. from their Moslem neighbors within the country and from the rest of the Jewish Diabetes Care 24:650–653, 2001 diaspora. However, during the same pe- riod, thousands of other immigrants ar- rived in Israel from all over the world, and he incidence of type 1 diabetes ex- type 1 diabetes genes (1,2). The develop- all were exposed to a similar environ- hibits a marked geographic varia- ment of the disease has been associated ment. The unusual rise in the incidence of T tion worldwide, probably resulting with polymorphism within the peptide type 1 diabetes among the Yemenites in- from different distributions of susceptible binding sites of the class II molecules dicates that they may differ in genetic ●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●●● background from other Jews. From 1The Institute of Pediatric Endocrinology, SCMCI, and 2The Laboratory of Diabetes and Obesity We have recently shown an excep- Research, FMRC, Petah Tikva, Sackler School of Medicine, Tel Aviv University, Tel Aviv; and 3the Depart- ment of Pediatric Endocrinology, the District of Haifa and Western Galilee, Haifa, and 4the Tissue Typing tionally high odds ratio for the universally Unit, Hadassah Medical Center, Hebrew University, Jerusalem, Israel. susceptible HLA diabetogenic genotype Address correspondence and reprint requests to Pnina Vardi, MD, The Laboratory of Diabetes and Obesity DRB1*03011,*0402 and its related DQ Research, Felsenstein Medical Research Center, Beilinson Campus, Petah Tikva, Israel. E-mail: alleles in Yemenite Jews with type 1 dia- [email protected]. Received for publication 15 August 2000 and accepted in revised form 21 December 2000. betes compared with nondiabetic Ye- A table elsewhere in this issue shows conventional and Syste`me International (SI) units and conversion menite control subjects (10). In the factors for many substances. present study, we further analyzed our

650 DIABETES CARE, VOLUME 24, NUMBER 4, APRIL 2001 Weintrob and Associates

Table 1—Distribution of HLA-DQB genotypes and non-Asp-57 gene frequencies among childhood diseases, such as pneumonia, Yemenite Jewish diabetic patients and unrelated control subjects gastroenteritis, and febrile convulsions. None were able to recall clinical symp- n (%) of n (%) of Fisher’s exact test Odds Odds ratio toms characteristic of type 1 diabetes in Allele patients control subjects (P) ratio 95% CI children or adolescents in the community in Yemen. In addition, no vaccination Ϫ N/N 39 (88) 23 (36) 3.1 ϫ 10 10 18 6.3–51.4 program against common childhood dis- Ϫ N/A 5 (11) 45 (59) 1.4 ϫ 10 7 0.09 0.03–0.25 eases was reported in Yemen. All the el- A/A 0 8 (10) 0.026 0.09 * derly women described the traditional Ϫ NAa 83 (94) 91 (60) 8.2 ϫ 10 10 11.1 4.3–29 early introduction of creamy cow’s milk to N/N, non-Asp-57 homozygosity; N/A, non-Asp-57 heterozygosity; A/A, Asp-57 homozygosity; NAa, non- neonates and infants in Yemen as a supple- Asp-57 alleles. *Biased due to reliance on zero-cell adjustment in computing the odds ratio. ment to breast-feeding during the first weeks of life. immunogenetic results in relation to var- lationship between ethnic groups and al- ious ethnic groups in Israel. In addition, leles (13). For the present study, we Molecular class II analysis we added structured interviews with el- assumed the independence of an assort- Results of this type analysis are shown in derly Yemenites who immigrated to Israel ment of alleles and performed the analysis Table 1. Homozygosity for DQB1 Asp-57- as adults in order to identify environmen- on the basis of alleles rather than individ- positive was present only in the healthy tal factors that may explain the dramatic uals. We used population-based multiple control subjects and was significantly de- change in the disease expression before correspondence analysis (a variant of the creased among the patients. By contrast, and after immigration. correspondence analysis method) of dis- we found a significant increase in non- tributions of allele families—that is, the Asp-57 homozygosity among the pa- RESEARCH DESIGN AND major genetic description of the allele tients. The gene frequencies of non- METHODS (e.g., DRB1*0402, DRB1*0404, and Asp-57 in the patients (0.94) and control DRB1*0405 are all members of the group (0.6) were similar to those found in Community inquiries DRB1*04 family). We mapped the ethnic other populations with a known high in- In this study, 196 elderly Yemenite groups for multiple dimensions in terms cidence of type 1 diabetes, such as Sardi- women who immigrated to Israel as of their similarities in allelic distribution. nians and Scandinavians. Plotting the adults during the early 1950s were ques- We compared type 1 diabetic subjects obtained frequencies over the figure of tioned in programmed interviews. Partic- from various Jewish and Arab communi- Dorman et al. (2) yielded an expected in- ular attention was paid to medical ties in Israel based on the results of their cidence of ϳ22/100,000 (Fig. 1), which is descriptions suggestive of type 1 diabetes HLA genotyping, including 44 Yemenites, slightly higher than the latest reported in- in children and adolescents of the com- 72 Ashkenazi, 33 Moroccans, and 36 Is- cidence of 18/100,000 (8). munity (i.e., polyuria, polydipsia, and raeli Arabs. weight loss), other common childhood The study protocol was approved by Correspondence analysis diseases, and vaccinations in Yemen. In- the Ethics Committee of Rabin Medical As depicted in Fig. 2, the multiple corre- formation on neonatal and infant feeding Center, and informed consent was ob- spondence analysis showed the relation- customs in Yemen was also obtained, es- tained from all participants. ships of Yemenite, Ashkenazi, and North pecially regarding exposure to cow’s milk. African Jews and Israeli Arabs in terms of Statistical analysis DRB1, DQB1, and DQA1 families of al- Molecular HLA class II analysis Fisher’s exact tests were used to evaluate leles. Our preliminary results suggest that Molecular HLA Class II analysis was per- the statistical significance of the associa- Yemenite Jews are genetically distinct formed in 120 unrelated individuals of tion between type 1 diabetes and Asp-57 from the other populations studied, in- unmixed Yemenite ancestry, including 44 alleles. Odds ratios for the development cluding Israeli Arabs. patients with type 1 diabetes (20 males) of type 1 diabetes and their 95% CI were and 76 healthy control subjects (47 determined when significant associations CONCLUSIONS — As we have pre- males) according to the 11th Interna- were found. In cases where correction viously reported (10), the Yemenite Jews tional Histocompatibility Workshop pro- was required for zero values, a value of 0.5 carry highly susceptible HLA class II tocol and as described previously (10,11). was used (as per the SAS software stan- genes for the development of type 1 dia- The relationship between the frequency dard). For data analysis, we used JMP ver- betes. However, the expression of these of the non-Asp-57 gene in patients and sion 3.2.2 and SAS 6.09 for Unix (both genes differs dramatically from before control subjects and the incidence of type products of the SAS Institute, Cary, NC) their immigration to Israel. Further anal- 1 diabetes was calculated with the and Excel 7.0 (Microsoft, Redmond, ysis of HLA typing shows a high non- method of Dorman et al. (2). WA). Asp-57 DQB1 gene frequency in both patients and control subjects, placing the Correspondence analysis RESULTS Yemenites near the top of the list of sus- Correspondence analysis is a statistical ceptible populations, between Sardinians and graphic method for comparing the Community inquiries and Norwegians (2). It should be noted, association among categorical variables The 196 elderly Yemenites questioned though, that non-Asp-57 in the control (12), and can be used to examine the re- gave detailed descriptions of common subjects was linked with DRB1*0701,

DIABETES CARE, VOLUME 24, NUMBER 4, APRIL 2001 651 Genetics, environment, and type 1 diabetes in Yemenite Jews

could indicate either no triggering effect classes developed later from major alleles, of cow’s milk or an interference with pro- this method allowed us to investigate dif- tective effects possibly induced by fre- ferent degrees of genetic distinctiveness. quent infections and the absence of a In this analysis, Yemenite Jews remained vaccination program in Yemen (14). The genetically distinct, suggesting a diver- influence of infection has also been dem- gence from the other populations in the onstrated in two animal models of type 1 distant past. Although similar models diabetes—NOD mice and BB rats—in have been previously constructed on the which differences in nutrition and hous- basis of genetic analysis of healthy sub- ing conditions led to great differences in jects, we assumed that the major histo- the incidence of diabetes (15–17). compatibility complex region, being only At the same time, we cannot ignore one of several genes responsible for type 1 the dramatic change in body size in the diabetes, and one that in the past has not Yemenite community in Israel over the associated with the disease, could repre- last 20 years, from an average weight and sent a population genomic inheritance height in adult males of 36 kg and 160 (13). Our results support the finding of cm, respectively, in 1950 to 63 kg and Bonne-Tamir et al. (20) that Yemenite Jews Figure 1—Relationship of non-Asp-57 alleles 171 cm, respectively, in 1971 (18). The differ by gene clustering from all other Jews. in various ethnic populations to incidence of relationship between body mass and The unique genetic background of this diabetes. Predicted incidences are based on ␤-cell autoimmunity is supported by the ethnic group is supported by its unusually U.S. whites as a point estimate. Observed inci- recently reported association of islet auto- high incidence of autosomal dominant dences are provided with the 95% CI. This fig- ␤ ␣ ure is adapted from Dorman et al. (2) with the immunity and -cell function abnormal- benign neutropenia (21), -thalassemia kind permission of Prof. J.S. Dorman, with the ity with obesity and insulin resistance with specific deletion in the ␣-globin gene addition of data for our Yemenite group. (19). (22), and phenylketonuria with specific The results of molecular HLA class II mutation in the phenylalanine hydroxy- typing of the Yemenite Jews differ sub- lase gene (23), as well as an exceptionally DQA1*0201, and DQB1*O2, a haplotype stantially from those obtained in other low incidence of familial Mediterranean suspected to be associated with resistance Jewish communities in Israel (S.I., O.J.K., fever (24), glucose-6-phosphate dehydrog- to type 1 diabetes in this community (10). N.W., E.S., P.V., C.B., unpublished ob- enase deficiency (25), and cystic fibrosis Thus, the nature of the association be- servation). Using these results for corre- (26). tween non-Asp-57 and type 1 diabetes spondence analysis (Fig. 2), our prelimi- In summary, the extraordinarily high development in Israeli Jews of Yemenite nary study shows that type 1 diabetic Jews frequency of genes associated with type 1 origin remains unclear; larger numbers of of Yemenite origin are distinct by class II diabetes in Yemenite Jews living in Israel diabetic patients, their healthy relatives, genes from every other ethnic group we might explain the high incidence of the and control subjects need to be tested. investigated. We used the allele familyϪ disease in this community; however, the Considering the high frequency of based taxonomy in our analytic approach. different expression of the genetic poten- type 1 diabetes susceptible genes among Based on the assumption that allelic sub- tial during a short period of time suggests Yemenite Jews and the continuing in- crease in the incidence of the disease in this community, we speculate that if en- vironmental conditions—such as low rate of mixed marriages and few effective pre- ventive manipulations—remain un- changed, an additional increase in disease prevalence is to be expected, equal to or exceeding that observed in Sardinia and Finland. Indeed, the latest report of Isra- el’s National Registry (1997–1998) indi- cates an incidence rate of 22/100,000 (Israel Type I Diabetes Registration Group, unpublished observation). This is compat- ible with the expected incidence predict- ed by Fig. 1 according to the frequency of the non-Asp-57 alleles in this population. Unexpectedly, our community in- quiry revealed an absence of type 1 diabe- tes in children of this community in Figure 2—Relationships of the genetic inheritance patterns of the various diabetic groups, as Yemen, despite the traditional early intro- shown by multiple correspondence analysis of DRB, DQA, and DQB allele family taxonomy. Axes duction of cow’s milk to neonates. This represent degree of relationship obtained from the analyses, such that proximity and similar lack of ␤-cell autoimmune destruction location indicate closeness.

652 DIABETES CARE, VOLUME 24, NUMBER 4, APRIL 2001 Weintrob and Associates an acute involvement of environmental I, Pietropaolo M, Dosch HM, Finberg of diabetes mellitus in non-obese diabetic factors. As the early introduction of cow’s L, Muir A, Tamborlane WV, Grey M, Sil- mice. Diabetologia 34:2–5, 1991 milk to neonates in this community in verstein JH, Malone JI: Therapeautic con- 18. Brunner D, Meshulam N, Altman S, Bear- Yemen did not induce ␤-cell autoimmu- troversy: prevention and treatment of di- man J, Loebel K, Wendkos E: Physiologic nity, different etiologic factors should be abetes in children. J Clin Endocrinol Metab and anthropometric parameters related to 85:498–522, 2000 sought. coronary risk factors in Yemenite Jews liv- 7. Laron Z, Karp M, Modan M: The inci- ing in different time spans in Israel. dence of insulin-dependent diabetes mel- J Chron Dis 24:383–392, 1971 litus in Israeli children and adolescents 19. Rolandson O, Haag E, Hampe C, Sullivan Acknowledgments— This study was par- 0–20 years of age: a retrospective study, EP, Nilsson M, Janson G, Hallmans G, tially supported by the U.S.-Israel Binational 1975–1980. Diabetes Care 8:24–28, 1985 Lernmark A: Glutamate decarboxylase Science Foundation Grant 93/265, the Chief 8. Shamis I, Gordon O, Albag Y, Goldsand (GAD65) and tyrosine phosphatase-like Scientist of the Ministry of Health Grant 2,669, G, Laron Z: Ethnic differences in the inci- protein (IA-2) autoantibodies in a re- and the Camp New York Diabetes Association dence of childhood type 1 diabetes in Is- and Sara Lea Foundations. gional population is related to glucose rael (1965–1993), marked increase since intolerance and body mass index. Dia- We acknowledge the major contribution of 1985, especially in Yemenite Jews. Diabe- Regina Ofan and Hadassah Ben-Zaken for or- betologia 42:555–559, 1999 tes Care 20:504–508, 1997 20. 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