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1.  HLA Class II Genotyping of African American Type 1 Diabetic Patients Reveals Associations Unique to African Haplotypes 
Diabetes  2013;62(9):3292-3299.
HLA genotyping was performed in African American type 1 diabetic patients (n = 772) and controls (n = 1,641) in the largest study of African Americans and type 1 diabetes reported to date. Cases were from Children’s Hospital and Research Center Oakland and from existing collections (Type 1 Diabetes Genetics Consortium [T1DGC], Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications [DCCT/EDIC], and Genetics of Kidneys in Diabetes [GoKinD]). Controls were from the T1DGC and from newborn bloodspot cards. The diversity of HLA DRB1-DQA1-DQB1 haplotypes and genotypes is far greater than that found in Europeans and European Americans. Association analyses replicated many type 1 diabetes risk effects of European-derived haplotypes but also revealed novel effects for African-derived haplotypes. Notably, the African-specific “DR3” haplotype DRB1*03:02-DQA1*04:01-DQB1*04:02 is protective for type 1 diabetes, in contrast to the common and highly-susceptible DR3 DRB1*03:01-DQA1*05:01-DQB1*02:01. Both DRB1*07:01 and DRB1*13:03 haplotypes are predisposing when they include DQA1*03:01-DQB1*02:01g but are protective with DQA1*02:01-DQB1*02:01g. The heterozygous DR4/DR9 genotype, containing the African-derived “DR9” haplotype DRB1*09:01-DQA1*03:01-DQB1*02:01g, exhibits extremely high risk (odds ratio = 30.88), approaching that for DR3/DR4 in European populations. Disease risk assessment for African Americans differs greatly from risk assessment in European populations. This has profound implications on risk screening programs and underscores the need for high-resolution genotyping of multiple populations for the rational design of screening programs with tests that will fairly represent the population being screened.
PMCID: PMC3749336  PMID: 23801574
2.  Race-Specific Type 1 Diabetes Risk of HLA-DR7 Haplotypes 
Tissue antigens  2011;78(5):348-351.
To test the hypothesis that closely-related HLA haplotypes containing the DRB1*07:01 gene (“DR7” haplotypes) derived from European and African populations differ in their genetic susceptibility for type 1 diabetes (T1D) depending on the DQ-α molecule present.
Research Design and Methods
A combined total of ninety-eight African American T1D patients from the Type 1 Diabetes Genetics Consortium and from Children’s Hospital and Research Center Oakland were genotyped for the HLA class II loci DRB1, DQA1, and DQB1. DNA samples extracted from newborn blood spot cards from African Americans born in California (n=947) were used as a population-based control group.
Among African American cases, the European-derived DRB1*07:01-DQA1*02:01-DQB1*02:01g haplotype was protective for T1D risk (odds ratio (OR)=0.34; 95% CI 0.14 - 0.78; p<0.011), but the African-derived DRB1*07:01-DQA1*03:01-DQB1*02:01g haplotype increased T1D risk (OR=3.96; 95% CI 1.94 - 8.08; p<5.5E-05).
The effect of DRB1*07:01-DQB1*02:01g on T1D susceptibility depends on the DQA1 allele. DRB1*07:01-DQA1*02:01-DQB1*02:01g is protective for T1D however, the presence of DQA1*03:01 on the DRB1*07:01-DQB1*02:01g haplotype not only renders the DR7 haplotype not protective, it creates a haplotype with significant T1D risk. These data underscore the importance of assessing genetic effects within ethnic context.
PMCID: PMC3193161  PMID: 21988721
type 1 diabetes; genetic risk; HLA class II; HLA DR7; African American
3.  The rs4774 CIITA missense variant is associated with risk of systemic lupus erythematosus 
Genes and Immunity  2011;12(8):667-671.
The major histocompatibility complex (MHC) class II transactivator gene (CIITA) encodes an important transcription factor required for HLA class II MHC-restricted antigen presentation. MHC genes, including the HLA class II DRB1*03:01 allele, are strongly associated with systemic lupus erythematosus (SLE). Recently the rs4774 CIITA missense variant (+1632G/C) was reported to be associated with susceptibility to multiple sclerosis. In the current study, we investigated CIITA, DRB1*03:01 and risk of SLE using a multi-stage analysis. In stage 1, 9 CIITA variants were tested in 658 cases and 1,363 controls (N = 2,021). In stage 2, rs4774 was tested in 684 cases and 2,938 controls (N = 3,622). We also performed a meta-analysis of the pooled 1,342 cases and 4,301 controls (N = 5,643). In stage 1, rs4774*C was associated with SLE (odds ratio [OR] = 1.24, 95% confidence interval [95% CI] = 1.07–1.44, P = 4.2 × 10−3). Similar results were observed in stage 2 (OR = 1.16, 95% CI = 1.02–1.33, P = 8.5×10−3) and the meta-analysis of the combined dataset (OR = 1.20, 95% CI = 1.09–1.33, Pmeta = 2.5×10−4). In all three analyses, the strongest evidence for association between rs4774*C and SLE was present in individuals who carried at least one copy of DRB1*03:01 (Pmeta= 1.9×10−3). Results support a role for CIITA in SLE, which appears to be stronger in the presence of DRB1*03:01.
PMCID: PMC3387803  PMID: 21614020
systemic lupus erythematosus; autoimmunity; major histocompatibility complex; HLA; CIITA; MHC2TA
4.  Promoting advance planning for health care and research among older adults: A randomized controlled trial 
BMC Medical Ethics  2012;13:1.
Family members are often required to act as substitute decision-makers when health care or research participation decisions must be made for an incapacitated relative. Yet most families are unable to accurately predict older adult preferences regarding future health care and willingness to engage in research studies. Discussion and documentation of preferences could improve proxies' abilities to decide for their loved ones. This trial assesses the efficacy of an advance planning intervention in improving the accuracy of substitute decision-making and increasing the frequency of documented preferences for health care and research. It also investigates the financial impact on the healthcare system of improving substitute decision-making.
Dyads (n = 240) comprising an older adult and his/her self-selected proxy are randomly allocated to the experimental or control group, after stratification for type of designated proxy and self-report of prior documentation of healthcare preferences. At baseline, clinical and research vignettes are used to elicit older adult preferences and assess the ability of their proxy to predict those preferences. Responses are elicited under four health states, ranging from the subject's current health state to severe dementia. For each state, we estimated the public costs of the healthcare services that would typically be provided to a patient under these scenarios. Experimental dyads are visited at home, twice, by a specially trained facilitator who communicates the dyad-specific results of the concordance assessment, helps older adults convey their wishes to their proxies, and offers assistance in completing a guide entitled My Preferences that we designed specifically for that purpose. In between these meetings, experimental dyads attend a group information session about My Preferences. Control dyads attend three monthly workshops aimed at promoting healthy behaviors. Concordance assessments are repeated at the end of the intervention and 6 months later to assess improvement in predictive accuracy and cost savings, if any. Copies of completed guides are made at the time of these assessments.
This study will determine whether the tested intervention guides proxies in making decisions that concur with those of older adults, motivates the latter to record their wishes in writing, and yields savings for the healthcare system.
Trial Registration
PMCID: PMC3328256  PMID: 22221980
5.  HLA Class I and Genetic Susceptibility to Type 1 Diabetes 
Diabetes  2010;59(11):2972-2979.
We report here genotyping data and type 1 diabetes association analyses for HLA class I loci (A, B, and C) on 1,753 multiplex pedigrees from the Type 1 Diabetes Genetics Consortium (T1DGC), a large international collaborative study.
Complete eight-locus HLA genotyping data were generated. Expected patient class I (HLA-A, -B, and -C) allele frequencies were calculated, based on linkage disequilibrium (LD) patterns with observed HLA class II DRB1-DQA1-DQB1 haplotype frequencies. Expected frequencies were compared to observed allele frequencies in patients.
Significant type 1 diabetes associations were observed at all class I HLA loci. After accounting for LD with HLA class II, the most significantly type 1 diabetes–associated alleles were B*5701 (odds ratio 0.19; P = 4 × 10−11) and B*3906 (10.31; P = 4 × 10−10). Other significantly type 1 diabetes–associated alleles included A*2402, A*0201, B*1801, and C*0501 (predisposing) and A*1101, A*3201, A*6601, B*0702, B*4403, B*3502, C*1601, and C*0401 (protective). Some alleles, notably B*3906, appear to modulate the risk of all DRB1-DQA1-DQB1 haplotypes on which they reside, suggesting a class I effect that is independent of class II. Other class I type 1 diabetes associations appear to be specific to individual class II haplotypes. Some apparent associations (e.g., C*1601) could be attributed to strong LD to another class I susceptibility locus (B*4403).
These data indicate that HLA class I alleles, in addition to and independently from HLA class II alleles, are associated with type 1 diabetes.
PMCID: PMC2963558  PMID: 20798335
6.  Maximizing Deoxyribonucleic Acid Yield from Dried Blood Spots 
One source of deoxyribonucleic acid (DNA) for genetic studies is the utilization of dried blood spots stored on paper cards (Guthrie cards) collected shortly after birth. These cards represent an important source of material for epidemiologic and population-based genetic studies. Extraction of DNA from these cards can lead to variable amounts of recovered DNA. We report here results of our efforts to maximize yield from this valuable, but nonrenewable, resource.
Commercial methods of DNA extraction from blood cards were used, and protocol modifications were introduced that enhanced DNA yield.
Use of a commercial solvent prior to DNA extraction steps gave greater yields than extraction without the solvent. Modification of the elution step by use of prewarmed extraction buffer and a soaking step at an elevated temperature increased yield by 6- to 10-fold.
The modified DNA extraction method yielded as much as 660 ng of DNA from a single 5-mm-diameter punch of a blood spot card. The DNA performed well in downstream, polymerase chain reaction-based applications.
PMCID: PMC2864159  PMID: 20307384
blood spot; DNA sample preparation; Guthrie card; HLA genotyping
7.  Analysis of Maternal–Offspring HLA Compatibility, Parent-of-Origin Effects, and Noninherited Maternal Antigen Effects for HLA–DRB1 in Systemic Lupus Erythematosus 
Arthritis and rheumatism  2010;62(6):1712-1717.
Genetic susceptibility to systemic lupus erythematosus (SLE) is well established, with the HLA class II DRB1 and DQB1 loci demonstrating the strongest association. However, HLA may also influence SLE through novel biologic mechanisms in addition to genetic transmission of risk alleles. Evidence for increased maternal–offspring HLA class II compatibility in SLE and differences in maternal versus paternal transmission rates (parent-of-origin effects) and nontransmission rates (noninherited maternal antigen [NIMA] effects) in other autoimmune diseases have been reported. Thus, we investigated maternal–offspring HLA compatibility, parent-of-origin effects, and NIMA effects at DRB1 in SLE.
The cohort comprised 707 SLE families and 188 independent healthy maternal–offspring pairs (total of 2,497 individuals). Family-based association tests were conducted to compare transmitted versus nontransmitted alleles (transmission disequilibrium test) and both maternally versus paternally transmitted (parent-of-origin) and nontransmitted alleles (using the chi-square test of heterogeneity). Analyses were stratified according to the sex of the offspring. Maternally affected offspring DRB1 compatibility in SLE families was compared with paternally affected offspring compatibility and with independent control maternal–offspring pairs (using Fisher’s test) and was restricted to male and nulligravid female offspring with SLE.
As expected, DRB1 was associated with SLE (P < 1 × 10−4). However, mothers of children with SLE had similar transmission and nontransmission frequencies for DRB1 alleles when compared with fathers, including those for the known SLE risk alleles HLA–DRB1*0301, *1501, and *0801. No association between maternal–offspring compatibility and SLE was observed.
Maternal–offspring HLA compatibility, parent-of-origin effects, and NIMA effects at DRB1 are unlikely to play a role in SLE.
PMCID: PMC2948464  PMID: 20191587
8.  HLA genotyping in the international Type 1 Diabetes Genetics Consortium 
Clinical Trials (London, England)  2010;7(1_supplement):S75-S87.
Background Although human leukocyte antigen (HLA) DQ and DR loci appear to confer the strongest genetic risk for type 1 diabetes, more detailed information is required for other loci within the HLA region to understand causality and stratify additional risk factors. The Type 1 Diabetes Genetics Consortium (T1DGC) study design included high-resolution genotyping of HLA-A, B, C, DRB1, DQ, and DP loci in all affected sibling pair and trio families, and cases and controls, recruited from four networks worldwide, for analysis with clinical phenotypes and immunological markers.
Purpose In this article, we present the operational strategy of training, classification, reporting, and quality control of HLA genotyping in four laboratories on three continents over nearly 5 years.
Methods Methods to standardize HLA genotyping at eight loci included: central training and initial certification testing; the use of uniform reagents, protocols, instrumentation, and software versions; an automated data transfer; and the use of standardized nomenclature and allele databases. We implemented a rigorous and consistent quality control process, reinforced by repeated workshops, yearly meetings, and telephone conferences.
Results A total of 15,246 samples have been HLA genotyped at eight loci to four-digit resolution; an additional 6797 samples have been HLA genotyped at two loci. The genotyping repeat rate decreased significantly over time, with an estimated unresolved Mendelian inconsistency rate of 0.21%. Annual quality control exercises tested 2192 genotypes (4384 alleles) and achieved 99.82% intra-laboratory and 99.68% inter-laboratory concordances.
Limitations The chosen genotyping platform was unable to distinguish many allele combinations, which would require further multiple stepwise testing to resolve. For these combinations, a standard allele assignment was agreed upon, allowing further analysis if required.
Conclusions High-resolution HLA genotyping can be performed in multiple laboratories using standard equipment, reagents, protocols, software, and communication to produce consistent and reproducible data with minimal systematic error. Many of the strategies used in this study are generally applicable to other large multi-center studies.
PMCID: PMC2917849  PMID: 20595243
9.  High-Density SNP Screening of the Major Histocompatibility Complex in Systemic Lupus Erythematosus Demonstrates Strong Evidence for Independent Susceptibility Regions 
PLoS Genetics  2009;5(10):e1000696.
A substantial genetic contribution to systemic lupus erythematosus (SLE) risk is conferred by major histocompatibility complex (MHC) gene(s) on chromosome 6p21. Previous studies in SLE have lacked statistical power and genetic resolution to fully define MHC influences. We characterized 1,610 Caucasian SLE cases and 1,470 parents for 1,974 MHC SNPs, the highly polymorphic HLA-DRB1 locus, and a panel of ancestry informative markers. Single-marker analyses revealed strong signals for SNPs within several MHC regions, as well as with HLA-DRB1 (global p = 9.99×10−16). The most strongly associated DRB1 alleles were: *0301 (odds ratio, OR = 2.21, p = 2.53×10−12), *1401 (OR = 0.50, p = 0.0002), and *1501 (OR = 1.39, p = 0.0032). The MHC region SNP demonstrating the strongest evidence of association with SLE was rs3117103, with OR = 2.44 and p = 2.80×10−13. Conditional haplotype and stepwise logistic regression analyses identified strong evidence for association between SLE and the extended class I, class I, class III, class II, and the extended class II MHC regions. Sequential removal of SLE–associated DRB1 haplotypes revealed independent effects due to variation within OR2H2 (extended class I, rs362521, p = 0.006), CREBL1 (class III, rs8283, p = 0.01), and DQB2 (class II, rs7769979, p = 0.003, and rs10947345, p = 0.0004). Further, conditional haplotype analyses demonstrated that variation within MICB (class I, rs3828903, p = 0.006) also contributes to SLE risk independent of HLA-DRB1*0301. Our results for the first time delineate with high resolution several MHC regions with independent contributions to SLE risk. We provide a list of candidate variants based on biologic and functional considerations that may be causally related to SLE risk and warrant further investigation.
Author Summary
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoantibody production and involvement of multiple organ systems. Although the cause of SLE remains unknown, several lines of evidence underscore the importance of genetic factors. As is true for most autoimmune diseases, a substantial genetic contribution to disease risk is conferred by major histocompatibility complex (MHC) gene(s) on chromosome 6. This region of the genome contains a large number of genes that participate in the immune response. However, the full contribution of this genomic region to SLE risk has not yet been defined. In the current study we characterize a large number of SLE patients and family members for approximately 2,000 MHC region variants to identify the specific genes that influence disease risk. Our results, for the first time, implicate four different MHC regions in SLE risk. We provide a list of candidate variants based on biologic and functional considerations that may be causally related to SLE risk and warrant further investigation.
PMCID: PMC2758598  PMID: 19851445
10.  Type 1 diabetes risk for HLA-DR3 haplotypes depends on genotypic context: Association of DPB1 and HLA class I loci among DR3 and DR4 matched Italian patients and controls 
Human immunology  2008;69(4-5):291-300.
Patients with high-risk HLA-DR-DQ genotypes for type 1 diabetes (T1D) were compared to HLA-matched controls to evaluate T1D risk for other HLA loci, including HLA-A, -B, -Cw, and DPB1. Patients (n=133) with high-risk genotypes (DR3/DR3, DR3/DR4, DR4/DR4) were selected from the Lazio (Rome) region of Italy. Screening of more than 9000 subjects from the Lazio region and northern Italy yielded 162 controls with high- T1D-risk haplotypes. Although the overall distributions were not significantly different, allele frequency differences were discovered between the controls from Lazio and those from Northern Italy for some alleles previously shown to affect T1D risk, such as A*3002, DPB1*0301, and DPB1*0402. Therefore, Lazio patient data were compared both to the Lazio subset of controls (n=53) and to the entire group of controls for association analyses. Significant allele frequency differences between patients and DR-DQ-matched controls were found for specific alleles at all loci. Data for the DR3/DR3 subset of patients and controls showed an increase of Cw*0702 in patients. Reduced patient, compared to control, frequencies were seen for several alleles, including A*0101, B*0801, and Cw*0701, all found on the highly-conserved, extended DR3 haplotype known as 8.1 in DR3/DR3, but not DR3/DR4, subgroup. DPB1*0101, often found on 8.1 haplotypes, was also less frequent in DR3/DR3 patients than controls. Analysis of family-based data from the HBDI repository was consistent with the observed results from the Italian subjects, suggesting the presence of a T1D-protective locus at or near A*0101 and a second T1D-protective locus at or near DPB1*0101. These data suggest that T1D risk conferred by the 8.1 haplotype is genotype dependent.
PMCID: PMC2505335  PMID: 18486765
HLA Class I; DPB1; Type 1 Diabetes; DR3 haplotype; Disease Association
11.  Linkage disequilibrium with predisposing DR3 haplotypes accounts for apparent effects of TNF and LTA polymorphisms on T1D susceptibility 
Human immunology  2006;67(12):999-1004.
Tumor necrosis factor (TNF) and lymphotoxin alpha (LTA) are immunomodulators that have been hypothesized to contribute to susceptibility to type 1 diabetes (T1D). Several polymorphisms in the TNF and LTA loci have been extensively studied for T1D association, with conflicting reports. In this study, we examined two TNF variants and one LTA variant for T1D association in 283 Caucasian, multiplex T1D families, for which complete HLA genotyping data are available. Initially, association with T1D was seen for LTA A1069G (intron A) (p = 0.011) {rs909253} and TNF G(-308)A (p< 1x 10−5) {rs1800629}, but no association was observed for TNF G(-238)A {rs361525}. After adjusting the data for linkage disequilibrium (LD) with DRB1-DQB1 haplotypes, however, only TNF G(-238)A showed significant association with T1D (p< 0.006). When HLA-DR3 haplotypes were examined, the A allele of TNF G(-238)A was significantly overtransmitted to affected offspring (p< 0.009). Including HLA-B data in the analysis revealed that TNF (-238)A is present exclusively on DR3 haplotypes that also carry HLA-B18. Transmission proportion of B18-DR3 haplotypes did not differ between those with TNF (-238)A and those with TNF (-238)G. Thus, variation at TNF does not affect the T1D risk for B18-DR3 haplotypes, and the apparent association of TNF(-238)A with T1D may simply reflect its presence on a high-risk haplotype.
PMCID: PMC2481238  PMID: 17174749
TNF; Polymorphisms; HLA; Type 1 diabetes; Linkage disequilibrium
12.  Prise de suppléments multivitaminiques pour la prévention primaire des anomalies congénitalies 
Canadian Family Physician  2007;53(12):2142-2143.
Déterminer si les recommandations véhiculées par les professionnels de la santé sur l’importance de l’acide folique encouragent les femmes susceptibles de procréer de prendre les suppléments d’acide folique.
Centre de santé et de services sociaux, Institut universitaire de gériatrie de Sherbrooke, à Sherbrooke, Qué.
323 femmes francophones âgées entre 18 et 45 ans.
La consommation de suppléments de vitamines et de minéraux au cours de la dernière année. Des analyses statistiques descriptives et bivariées et une modélisation par régression logistique ont été effectuées pour déterminer si l’association observée entre la recommandation d’un professionnel de la santé et la consommation de vitamines et de minéraux persistait après avoir tenu compte de l’effet des variables de contrôle (consultation de documentation, connaissances, sources d’information, perception, âge, scolarité, revenu, état matrimonial, intention de devenir enceinte).
Environ 41% des femmes rapportent que leur médecin leur avait recommandé de consommer un supplément de vitamines et de minéraux. Après avoir ajusté toutes les variables dans le modèle, il est apparu que le fait de se faire recommander par un professionnel de la santé de prendre un supplément de vitamines et de minéraux était significativement associé à la consommation de vitamines et de minéraux par les femmes susceptibles de devenir enceintes.
Les professionnels peuvent améliorer la santé de la population par une pratique clinique préventive. Nous soulignons l’importance de soutenir ces derniers dans leurs efforts d’intégrer puis d’appliquer des connaissances scientifiques dans leur pratique.
PMCID: PMC2231555  PMID: 18077754

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