HLA-DQ and susceptibility to celiac disease: evidence for gender differences and parent-of-origin effects

Sex- and gender-based medicine in pediatric nutrition

Consistent evidence increasingly highlights the significance of integrating sex and gender medicine to ensure a precision approach according to individual patient needs. Gender discrepancies emerge across various areas, even from pediatric age. The importance of recognizing these differences in pediatric nutrition is critical for the development of targeted nutritional strategies and interventions, particularly in cases of associated pathologies, including obesity, metabolic-associated fatty liver disease, eating disorders, and inflammatory bowel disease. The review highlights the biological and sociocultural factors that contribute to different nutritional needs and health outcomes in male and female children. By examining current evidence, we underscore the necessity for precision medicine approaches in pediatric care that consider these sex- and gender-based differences. Moreover, differences in dietary requirements and dietary patterns between males and females are evident, underscoring the need for precise nutrition strategies for a more accurate management of children and adolescents. This approach is essential for improving clinical outcomes and promoting equitable healthcare practices. This review aims to provide an overview of nutrition-related medical conditions exhibiting sex- and gender-specific discrepancies, which might lead to distinct outcomes requiring unique management and prevention strategies. Future research and public health initiatives should address these differences in designing effective lifestyle education programs and nutrition interventions targeting both children and adolescents.

Eating Attitudes of Patients with Celiac Disease in Brazil: A Nationwide Assessment with the EAT-26 Instrument

Celiac disease (CD) is an immune-mediated enteropathy triggered by the ingestion of gluten in genetically predisposed individuals. In this sense, a gluten-free diet is the only safe treatment available. Due to the restrictions resulting from this eating pattern, this treatment may impair the relationship of the people with CD with food, increasing the risk of a disordered eating attitude, which is associated with eating disorders. The EAT-26 is a validated instrument already applied worldwide in different populations, and higher scores are suggestive of eating attitudes prone to evolve into eating disorders. Studies carried out in other countries have already shown that people with CD are prone to developing eating disorders; however, no study has been carried out with this theme in the population with CD in Brazil. We carried out a nationwide cross-sectional study in three steps: (i) study design and instrument; (ii) recruitment of participants and ethics; (iii) statistical analysis. A total of 385 participants were included in our sample, 96.36% of them being women. The internal consistency of the applied self-administered Brazilian version of the EAT-26 online questionnaire presented a satisfactory Cronbach's alpha of 0.812, and in total, 36.1% of the respondents were classified with a disordered eating attitude. No differences were found among the scores of participants when divided by categories regarding gender, average monthly income, age, and educational level. However, scores classified as a disordered eating attitude were found in respondents with a body mass index classified as overweight and obese. Our study highlights that disordered eating attitudes are present in overweight and obese women with celiac disease; thus, public health politics are needed to prevent and treat these attitudes.

Human Leukocyte Antigen-DQ Genotyping in Pediatric Celiac Disease

PURPOSE

The purpose of this study was to determine the pattern of human leukocyte antigen (HLA)-DQ genotype in children diagnosed with celiac disease (CD) (biopsy proven), and to compare this with a control group; and secondarily, to correlate HLA genotypes with clinical profiles of CD.

METHODS

This cross-sectional comparative observational study included 26 controls and 52 patients diagnosed with CD who presented at Sir Padampat Mother and Child Health Institute, Jaipur, from May, 2017 to October, 2018. HLA DQ genotype was assessed for each patients and correlated with clinical profiles.

RESULTS

HLA DQ2/DQ8 genotypes were significantly more common in CD (present in 100.0% cases) than in controls (23.1%) in Northern India (Rajasthan). When HLA DQ2.5 and DQ8 were present together, individuals had significantly more atypical presentations and severe findings on duodenal biopsy. Similarly, patients with the HLA DQ 2.5 genotype were also predisposed to more severe endoscopic findings, while HLA DQ2.2 predisposed them to less severe biopsy findings. HLA DQ8 was significantly associated with later age at diagnosis (>5 years) and shorter stature. The highest HLA DQ relative risk (RR) for CD development was associated with HLA DQ2.5 and DQ2.2 in combination, followed by HLA DQ2.5 and DQ8 in combination, while HLA DQx.5 and HLA DQ2.2 together had the lowest risk.

CONCLUSION

HLA DQ2/DQ8 genotypes are strongly associated with pediatric CD patients in northern India. These genotypes and their combinations may be associated with different clinical presentations of CD, and may help predict severity of CD.

HLA Allele Prevalence in Disease-Modifying Antirheumatic Drugs-Responsive Enthesitis and/or Arthritis Not Fulfilling ASAS Criteria: Comparison with Psoriatic and Undifferentiated Spondyloarthritis

Spondyloarthritis (SpA) is a group of inflammatory rheumatic diseases characterized by common clinical features, such as inflammatory enthesitis, arthritis and/or back pain. SpA is strongly associated with human leukocyte antigen (HLA) class I allotype B27. Ankylosing spondylitis has historically been the SpA subgroup with one of the strongest, best-proven associations with HLA-B27. The remaining SpA subgroups, namely psoriatic arthritis (PsA), inflammatory bowel diseases-associated arthritis/spondylitis, reactive arthritis, and undifferentiated SpA (uSpA), have also been associated with HLA allotypes other than HLA-B27. In this retrospective study, we analyzed the association between the HLA class I and II haplotypes and the susceptibility to enthesitis and/or arthritis (E/A). Special attention was paid to E/A responding to disease-modifying antirheumatic drugs (DMARDs) not fulfilling ASAS classification criteria (ASAS⁻), as compared to ASAS⁺ forms including PsA and uSpA. The whole E/A group showed significant independent associations with HLA-A28(68), B27, Cw3, Cw12, and DQ1; taken singly, PsA was associated with HLA-B27 and DQ1, uSpA with HLA-B16(38,39) and B27, and E/A ASAS⁻ with HLA-A28(68), Cw8, and Cw12. This study identified novel risk HLA allotypes for different SpA subgroups in an Italian population. HLA typing could aid the diagnosis and treatment of E/A subgroups, including DMARDS-responsive forms not fulfilling ASAS classification criteria.

Understanding celiac disease monitoring patterns and outcomes after diagnosis: A multinational, retrospective chart review study

BACKGROUND

Long-term outcomes and monitoring patterns in real-world practice are largely unknown among patients with celiac disease.

AIM

To understand patterns of follow-up and management of patients with celiac disease, and to characterize symptoms and villous atrophy after diagnosis.

METHODS

A retrospective chart review study was performed using medical chart data of patients diagnosed with celiac disease. Three gastroenterology referral centers, with substantial expertise in celiac disease, participated in the United Kingdom, United States, and Norway. Demographic and clinical data were collected from medical charts. Descriptive analyses were conducted on patients with biopsy-confirmed celiac disease, diagnosed between 2008 and 2012, with at least one follow-up visit before December 31, 2017. Patient demographic and clinical characteristics, biopsy/serology tests and results, symptoms, and comorbidities were captured at diagnosis and for each clinic visit occurring within the study period (i.e., before the study end date of December 31, 2017).

RESULTS

A total of 300 patients were included in this study [72% female; mean age at diagnosis: 38.9 years, standard deviation (SD) 17.2]. Patients were followed-up for a mean of 29.9 mo (SD 22.1) and there were, on average, three follow-up visits per patient during the study period. Over two-thirds (68.4%) of patients were recorded as having ongoing gastrointestinal symptoms and 11.0% had ongoing symptoms and enteropathy during follow-up. Approximately 80% of patients were referred to a dietician at least once during the follow-up period. Half (50.0%) of the patients underwent at least one follow-up duodenal biopsy and 36.6% had continued villous atrophy. Patterns of monitoring varied between sites. Biopsies were conducted more frequently in Norway and patients in the United States had a longer follow-up duration.

CONCLUSION

This real-world study demonstrates variable follow-up of patients with celiac disease despite most patients continuing to have abnormal histology and symptoms after diagnosis.

Clinical Presentation in Children With Coeliac Disease in Central Europe

OBJECTIVES

During the past decades, there has been a shift in the clinical presentation of coeliac disease (CD) to nonclassical, oligosymptomatic, and asymptomatic forms. We assessed clinical presentation of CD in children and adolescents in Central Europe.

METHODS

Paediatric gastroenterologists in 5 countries retrospectively reported data of their patients diagnosed with CD. Clinical presentation was analyzed and the differences among very young (<3 years) and older children and adolescents were studied.

RESULTS

Data from 653 children and adolescents (median age 7 years 2 months; 63.9% girls) from Croatia, Germany, Hungary, Italy, and Slovenia were available for the analysis. One fifth (N = 134) of all children were asymptomatic. In symptomatic children, the most common leading symptom was abdominal pain (33.3%), followed by growth retardation (13.7%) and diarrhoea (13.3%). The majority of symptomatic children (47.6%; N = 247) were polysymptomatic. Abdominal pain was the most common symptom in polysymptomatic (66.4%) as well as in monosymptomatic children (29.7%). Comparing clinical presentation of CD in very young children (younger than 3 years) with older children (3 years or older), we found that symptoms and signs of malabsorption were significantly more common in younger (P < 0.001), whereas abdominal pain and asymptomatic presentation were more common in older children and adolescents (both P < 0.001).

CONCLUSION

In children with CD, abdominal pain has become the most common symptom. However, in younger children, symptoms of malabsorption are still seen frequently. This raises a question about the underlying mechanism of observed change in clinical presentation in favour of nonclassical presentation and asymptomatic disease at certain age.

Sex-specific differences in peripheral blood leukocyte transcriptional response to LPS are enriched for HLA region and X chromosome genes

Sex-specific differences in prevalence are well documented for many common, complex diseases, especially for immune-mediated diseases, yet the precise mechanisms through which factors associated with biological sex exert their effects throughout life are not well understood. We interrogated sex-specific transcriptional responses of peripheral blood leukocytes (PBLs) to innate immune stimulation by lipopolysaccharide (LPS) in 46 male and 66 female members of the Hutterite community, who practice a communal lifestyle. We identified 1217 autosomal and 54 X-linked genes with sex-specific responses to LPS, as well as 71 autosomal and one X-linked sex-specific expression quantitative trait loci (eQTLs). Despite a similar proportion of the 15 HLA genes responding to LPS compared to all expressed autosomal genes, there was a significant over-representation of genes with sex by treatment interactions among HLA genes. We also observed an enrichment of sex-specific differentially expressed genes in response to LPS for X-linked genes compared to autosomal genes, suggesting that HLA and X-linked genes may disproportionately contribute to sex disparities in risk for immune-mediated diseases.

Clinical manifestations and associated disorders in children with celiac disease in southern Iran

Background

Celiac disease (CD) is an immune mediated inflammatory enteropathy, triggered by gluten exposure in HLA-DQ2 and/or –DQ8 genetics. The presentation of celiac disease in children is changing, with increase in non-classical symptoms. We aim to evaluate the clinical presentations of celiac disease amongst children, diagnosed with CD.

Methods

In this cross sectional study, we investigated the clinical features of 130 celiac patients at hospitals affiliated with Shiraz University of Medical Sciences. We used their hospital charts and conducted an interview with patients and their parents to find out demographic data, symptoms, laboratory, and histopathology findings for Marsh grading.

Results

Celiac disease was detected more amongst females (63.8%). We found that 5.4% of the patients had BMI more than 95th percentile. The most common GI symptoms were abdominal pain, flatulence and constipation. Also, the most common extra intestinal manifestation included bone pain, long term fatigue and anemia. Flatulence, chronic diarrhea, and paresthesia were observed more amongst male participants. The most common comorbidities were type 1 diabetes mellitus and hypothyroidism.

Conclusion

The most common gastrointestinal symptoms amongst our patients were abdominal pain, flatulence and constipation. Furthermore, the most common extra intestinal manifestations included bone pain, long term fatigue and anemia. The most associated comorbidities with CD in our children were type 1 diabetes mellitus and hypothyroidism.

Sex Difference in Celiac Disease in Undiagnosed Populations: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

A higher proportion of female vs male patients receive a diagnosis of celiac disease. Little is known about sex-based differences in the prevalence of celiac disease in undiagnosed populations. We aimed to address this knowledge gap with a systematic review and meta-analysis.

METHODS

We searched MEDLINE, Embase, Cochrane, and Scopus databases through 2017 for studies of screen-detected or undiagnosed celiac disease. Our final analysis included studies that included screening and confirmatory tests (either second serologic analysis or a small intestine biopsy) and provided information on the sex of participants. Studies were excluded if they were performed with specific, high-risk, or referral populations. The primary outcome was the percentage of undetected celiac disease among female and male patients.

RESULTS

We identified 4070 articles and analyzed data from 87. Our meta-analysis comprised data from 291,969 study participants. The pooled prevalence of undetected celiac disease in female participants was 0.589% (95% CI, 0.549%-0.629%) and in male participants was 0.415% (95% CI, 0.343%-0.487%). The risk of undetected celiac disease was higher among female than male participants (relative risk [RR], 1.42; 95% CI, 1.27-1.57; P < .00001). The I² was 5% (low heterogeneity among studies). In subgroup analyses, the RR of celiac disease for girls vs boys was 1.79 (95% CI, 1.44-2.22; P < .00001; I² = 18%), the RR for female vs male blood donors was 1.13 (95% CI, 0.76-1.69; P = .54; I² = 0), and the RR for women vs men with villous atrophy was 1.38 (95% CI, 1.07-1.79; P = .01; I² = 0).

CONCLUSIONS

In a systematic review and meta-analysis, we found a higher risk for celiac disease in women than men in an undiagnosed populations (identified through general population screening). The increased risk for celiac disease among girls and women should be considered for screening, diagnosis, and management strategies.

The Pregnancy Pickle: Evolved Immune Compensation Due to Pregnancy Underlies Sex Differences in Human Diseases

We hypothesize that, ancestrally, sex-specific immune modulation evolved to facilitate survival of the pregnant person in the presence of an invasive placenta and an immunologically challenging pregnancy - an idea we term the 'pregnancy compensation hypothesis' (PCH). Further, we propose that sex differences in immune function are mediated, at least in part, by the evolution of gene content and dosage on the sex chromosomes, and are regulated by reproductive hormones. Finally, we propose that changes in reproductive ecology in industrialized environments exacerbate these evolved sex differences, resulting in the increasing risk of autoimmune disease observed in females, and a counteracting reduction in diseases such as cancer that can be combated by heightened immune surveillance. The PCH generates a series of expectations that can be tested empirically and that may help to identify the mechanisms underlying sex differences in modern human diseases.

Screening for coeliac disease in 1624 mainly asymptomatic children with type 1 diabetes: is genotyping for coeliac-specific human leucocyte antigen the right approach?

OBJECTIVES

To investigate the frequency of coeliac disease (CD)-specific human leucocyte antigen (HLA) genotypes in paediatric patients with type 1 diabetes (T1D), who are known to have a higher prevalence of CD than the general population, and to evaluate whether HLA genotyping is a suitable first-line screening method for CD.

STUDY DESIGN

The study was a multicentre observational analysis of patients with T1D aged <20 years of whom a subgroup had undergone HLA genotyping. Patient data were retrieved from the Diabetes Prospective Follow-up database, a large diabetes follow-up registry. The present analysis included data from 439 centres throughout Germany, Austria, Switzerland and Luxembourg.

RESULTS

In March 2017, the database contained 75 202 patients with T1D (53% male, mean age (SD) 14.6 (4.1) years, mean age at diagnosis 8.8 (4.3) years and mean diabetes duration 5.8 (4.3) years). 1624 patients had undergone coeliac-specific HLA genotyping, of whom 1344 (82.8%) were positive for HLA-DQ2, HLA-DQ8 or both, while 17.2% had no coeliac-specific HLA-markers. 26.6% of at-risk patients had a clinical suspected diagnosis of CD, and 3.6% had biopsy-proven CD.

CONCLUSIONS

Genotyping for HLA-DQ2, HLA-DQ8 or both is positive in the vast majority (>80%) of patients with T1D. Therefore, screening for coeliac-specific HLA genotypes as a first-line test is not a suitable method to exclude CD in T1D. Regular screening for coeliac-specific antibodies in T1D is still recommended.

Tissue transglutaminase autoantibodies in children with newly diagnosed type 1 diabetes are related to human leukocyte antigen but not to islet autoantibodies: A Swedish nationwide prospective population-based cohort study

OBJECTIVES

This study explored the association between tissue transglutaminase autoantibody (tTGA), high-risk human leucocyte antigen (HLA) genotypes and islet autoantibodies in children with newly diagnosed type 1 diabetes (T1D).

PATIENTS AND METHODS

Dried blood spots and serum samples were taken at diagnosis from children <18 years of age participating in Better Diabetes Diagnosis (BDD), a Swedish nationwide prospective cohort study of children newly diagnosed with T1D. We analyzed tTGA, high-risk HLA DQ2 and DQ8 (DQX is neither DQ2 nor DQ8) and islet auto-antibodies (GADA, IA-2A, IAA, and three variants of Zinc transporter; ZnT8W, ZnT8R, and ZnT8QA).

RESULTS

Out of 2705 children diagnosed with T1D, 85 (3.1%) had positive tTGA and 63 (2.3%) had borderline values. The prevalence of tTGA was higher in children with the HLA genotypes DQ2/2, DQ2/X or DQ2/8 compared to those with DQ8/8 or DQ8/X (p = .00001) and those with DQX/X (p ≤ .00001). No significant differences were found in relation to islet autoantibodies or age at diagnosis, but the presence of tTGA was more common in girls than in boys (p = .018).

CONCLUSION

tTGA at T1D diagnosis (both positive and borderline values 5.4%) was higher in girls and in children homozygous for DQ2/2, followed by children heterozygous for DQ2. Only children with DQ2 and/or DQ8 had tTGA. HLA typing at the diagnosis of T1D can help to identify those without risk for CD.

A Retrospective Study on Dietary FODMAP Intake in Celiac Patients Following a Gluten-Free Diet

Our aim was to evaluate the intake of foods containing fermentable oligo/di/mono-saccharides and polyols (FODMAP) as a possible factor that induces gastrointestinal symptoms in treated celiac disease (CD) patients. We collected seven-day weighed food records for 104 CD patients and 91 healthy volunteers. All evaluated food items were from sources with high and low content of FODMAP, which were divided into cereals and sweets, sweeteners and soft drinks, fruits, dried fruits, and vegetables. Nutrient intake was calculated using the food database of the European Institute of Oncology. The symptoms reported were assessed by a Rome IV Irritable bowel syndrome (IBS) diagnostic questionnaire and by specific questions for the evaluation of functional gastrointestinal disorders (FGIDs). The 12% of CD patients met IBS symptoms criteria as opposed to 6% of controls (p = 0.09) and 27% of patients reported FGIDs symptoms vs. 22% of healthy controls (p = 0.42). The intake by CD patients was significantly higher than healthy volunteers for: sweeteners and sugars with low content of FODMAP (p = 0.0007), fruits, dried fruits, and vegetables high in FODMAP (p = 0.003) and low in FODMAP (p = 0.04) when compared to controls. CD patients had a lower intake of cereals and sweets with a high content of FODMAP (p = 0.00001). Healthy volunteers consumed significantly higher alcoholic beverages and fats high in FODMAP (both p < 0.044). The mean daily intake of other food categories did not differ between both groups. Even though CD patients had a low intake of gluten-free cereals high in FODMAP, they still consumed a significant amount of fruits and vegetables high in FODMAP. The clinical effect of a concomitant gluten-free diet and low-FODMAP diet should be prospectively evaluated as a supportive therapy in CD patients.

Celiac disease in non-clinical populations of Japan

BACKGROUND

Celiac disease is a chronic autoimmune enteropathy caused by gluten ingestion. While its prevalence in Western countries is reported to be as high as 1%, the prevalence has not been evaluated in a large-scale study of a Japanese population. The aim of our study was to clarify the possible presence of celiac disease in a Japanese non-clinical population as well as in patients showing symptoms suggestive of the disease.

METHODS

Serum samples were collected from 2008 non-clinical adults and 47 patients with chronic unexplained abdominal symptoms between April 2014 and June 2016. The anti-tissue transglutaminase (TTG) immunoglobulin A antibody titer was determined as a screening test for celiac disease in all subjects, and individuals with a value of >2 U/mL subsequently underwent testing for the presence of serum endomysial IgA antibody (EMA) as confirmation. Those testing positive for EMA or with a high concentration (>10 U/mL) of TTG were further investigated by histopathological examinations of duodenal mucosal biopsy specimens and HLA typing tests.

RESULTS

Of the 2008 non-clinical adults from whom serum samples were collected, 161 tested positive for TTG, and all tested negative for EMA. Four subjects who had a high TTG titer were invited to undergo confirmatory testing, and the histopathological results confirmed the presence of celiac disease in only a single case (0.05%). Of the 47 symptomatic patients, one (2.1%) was found to have a high TTG titer and was diagnosed with celiac disease based on duodenal histopathological findings.

CONCLUSION

The presence of celiac disease in a non-clinical Japanese population was low at 0.05% and was rarely found in patients with unexplained chronic abdominal symptoms.

HLA-DQ: Celiac disease vs inflammatory bowel disease

AIM

To determine the genetic predisposition to celiac disease (CeD) in inflammatory bowel disease (IBD) patients by quantifying the frequency of CeD-related human leucocyte antigen (HLA) (HLA-CeD: HLA-DQ2 and -DQ8) in IBD patients globally, by type of IBD and gender, and by calculating the protective/risk contribution of these haplotypes in the development of the IBD disease.

METHODS

We conducted a prospective study with IBD patients from our Unit. Clinical information was gathered and blood was tested for HLA-CeD. The control group was made up of unrelated Valencian organ donors.

RESULTS

1034 subjects were analyzed: 457 IBD [207 ulcerative coliti (UC) and 250 Crohn’s disease (CD)] patients and 577 healthy controls. 39% of the controls and 34% of the patients had HLA-CeD (P = 0.0852). HLA-DQ2 was less frequent in UC patients (P = 0.0287), and HLA-DQ8 in CD (P = 0.0217). In women with UC, the frequency of DQ2.5cis (DQB1*02:01-DQA1*05:01) was reduced ≥ 50% [P = 0.0344; preventive fraction (PF) = 13%]. PFs (7%-14%) were obtained with all HLA-CeD haplotypes. HLA DQB1*02:02-DQA1*02:01 (HLA-DQ2.2) was more frequent in CD patients with respect to controls (P = 0.001) and UC patients (etiological fraction = 15%).

CONCLUSION

HLA-CeD is not more frequent in IBD patients, with an even lower frequency of HLA-DQ2 and -DQ8 in UC and CD respectively. HLA-DQ2.5 confers protection from the development of UC, especially in women, and HLA-DQ8 does so for the appearance of CD. HLA-DQ2.2 is present in 34% of the CD patients and may constitute a genetic risk factor for CD development.

Genetic susceptibility for celiac disease is highly prevalent in the Saudi population

BACKGROUND/AIM

To determine the frequency of celiac disease (CD)-predisposing human leukocyte antigen (HLA)-DQ genotypes in the Saudi population, where the prevalence of CD is 1.5% as recently reported in a mass screening study.

PATIENTS AND METHODS

In a cross-sectional population-based study, a total of 192 randomly selected healthy school children (97 females, mean age 10.5 ± 2.2 years, all negative for tissue transglutaminase-IgA) were typed for D QA1 and D QB1 genes by polymerase chain reaction sequence-specific oligonucleotide probes.

RESULTS

Of the 192 children, 52.7% carried the high-risk CD-associated HLA-DQ molecules: homozygous DQ2.5 ( 2.6%), DQ2.5/DQ2.2 ( 4.7%), heterozygous DQ2.5 ( 28.15%), homozygous DQ8 ( 4.2%), DQ8/DQ2.2 ( 3.6%), and double dose DQ2.2 ( 9.4%). Low-risk CD-associated HLA-DQ molecules (single dose DQ2.2 and heterozygous DQ8) constituted 3.6% and 9.4%, respectively. Among the very low-risk groups, individuals lacking alleles that contribute to DQ2/DQ8 variants (33.5%), 13.5% carried only one of the alleles of the high-risk HLA-DQ2.5 heterodimer called "half-heterodimer" (HLA-DQA1*05 in 12% and HLA-DQB1* 02 in 1.5%), and 20.8% lacked all the susceptible alleles (DQX.x). Gender distribution was not significantly different among the CD-risk groups.

CONCLUSION

We report one of the highest frequencies of CD-predisposing HLA-DQ genotypes among healthy general populations (52.7%) worldwide, which might partly explain the high prevalence of CD in the Saudi community.

Presence of DQ2.2 Associated with DQ2.5 Increases the Risk for Celiac Disease

Background. Celiac disease (CD) is a genetically determined immune-mediated disorder in which gluten immunogenic peptides are presented to CD4 T cells by HLA-DQ2.5, DQ8, DQ2.2, and their combinations. Our aim is to establish a risk gradient for celiac disease based on HLA-DQ profile in a brazilian representative population and the relevance of DQ2.2 in celiac disease development. Materials and Methods. 237 celiac patients and 237 controls (both groups with 164 females and 73 males) were included. All samples were tested for the presence of predisposing HLA-DQ alleles using the PCR-SSP method. Results were considered significant when p < 0.05. Disease risk was expressed as 1 : N for each HLA-DQ category described at this study. Results. DQ2.5 and/or DQ8 were detected in 224 celiac patients (94.5%) and 84 controls (35.4%). Eight celiac patients (3.4%) and 38 controls (16%) disclosed only DQ2.2. Even though DQ2.2 (β2/β2 or β2/x) showed a low CD risk of 1 : 251 and 1 : 550, respectively, the genotype DQ2.5/DQ2.2 (β2/β2) showed high CD risk of 1 : 10 (p < 0.0001). The disease risk gradient ranged from 1 : 3014 to 1 : 7. Conclusion. Our study allowed the determination of a risk gradient for celiac disease development in at-risk population, showing that DQ2.2 variant was relevant when associated with DQ2.5.

Physicians Caring for Celiac Patients do not Routinely Recommend Screening of First-Degree Family Members

AIM

Screening first-degree relatives of celiac disease (CD) patients offers an opportunity to diagnose CD in a high-risk population.This study aims to determine how frequently CD patients receive a physician-issued recommendation for first-degree relative screening.

MATERIALS AND METHODS

A 12-question survey assessing whether CD patients receive a physician recommendation to screen first-degree relatives for CD, and the impact of such a recommendation, was validated with outpatients in a university gastroenterology practice ("University"). The 12-question survey was then distributed online to members of a celiac organization - the National Foundation for Celiac Awareness ("NFCA"). Results were collected over 3 months. Univariate analysis was used to compare cohort means and assess the association between demographic and diagnostic factors and first-degree relative screening recommendations.

RESULTS

87 University patients participated in the validation phase. Test-retest reliability of 4 key survey questions was high (Kappa coefficient > 0.80). The main analyses were based on data from 677 NFCA and 82 University respondents. Respondents were predominantly female, with a mean age of 45 years. Significantly more University patients received a recommendation for screening (78% vs 44%, p < 0.001). Ninety-eight percent receiving a screening recommendation (both groups) discussed this with family members, leading to CD screening (University 71%, NFCA 79%) and, ultimately, a CD diagnosis (University 18%, NFCA 27%).

CONCLUSIONS

Physicians of CD patients often do not recommend screening first-degree family members. The high clinical impact of this recommendation suggests that greater physician compliance with screening may increase the diagnosis of CD in high risk individuals.

Celiac Disease: Background and Historical Context

Medical descriptions of celiac disease date to the first century BC, and the first modern description was published in 1888. Further insights were gained throughout the 1900s, culminating in the identification of the dietary component, the major genetic determinant, and the autoantigen by the turn of the century. Understanding of the age of onset, population prevalence, and the extent of subclinical celiac disease developed in tandem. Thanks to advances in genomics, currently established loci account for over 50 % of the genetic risk. Nonetheless, much remains to be discovered. Advances in high-throughput genomic, biochemical, and cell analyses, as well as the bioinformatics needed to process the data, promise to deepen our understanding further. Here we present a primer of celiac disease, viewing the condition in turn from the historical, epidemiological, immunological, molecular, and genetic points of view. Research into any ailment has specific requirements: study subjects must be identified and relevant tissue samples collected and stored with the appropriate timing and conditions. These requirements are summarized. To conclude, a short discussion of future prospects is presented.

Combination Testing Using a Single MSH5 Variant alongside HLA Haplotypes Improves the Sensitivity of Predicting Coeliac Disease Risk in the Polish Population

Assessment of non-HLA variants alongside standard HLA testing was previously shown to improve the identification of potential coeliac disease (CD) patients. We intended to identify new genetic variants associated with CD in the Polish population that would improve CD risk prediction when used alongside HLA haplotype analysis. DNA samples of 336 CD and 264 unrelated healthy controls were used to create DNA pools for a genome wide association study (GWAS). GWAS findings were validated with individual HLA tag single nucleotide polymorphism (SNP) typing of 473 patients and 714 healthy controls. Association analysis using four HLA-tagging SNPs showed that, as was found in other populations, positive predicting genotypes (HLA-DQ2.5/DQ2.5, HLA-DQ2.5/DQ2.2, and HLA-DQ2.5/DQ8) were found at higher frequencies in CD patients than in healthy control individuals in the Polish population. Both CD-associated SNPs discovered by GWAS were found in the CD susceptibility region, confirming the previously-determined association of the major histocompatibility (MHC) region with CD pathogenesis. The two most significant SNPs from the GWAS were rs9272346 (HLA-dependent; localized within 1 Kb of DQA1) and rs3130484 (HLA-independent; mapped to MSH5). Specificity of CD prediction using the four HLA-tagging SNPs achieved 92.9%, but sensitivity was only 45.5%. However, when a testing combination of the HLA-tagging SNPs and the MSH5 SNP was used, specificity decreased to 80%, and sensitivity increased to 74%. This study confirmed that improvement of CD risk prediction sensitivity could be achieved by including non-HLA SNPs alongside HLA SNPs in genetic testing.

High Frequency of Haplotype HLA-DQ7 in Celiac Disease Patients from South Italy: Retrospective Evaluation of 5,535 Subjects at Risk of Celiac Disease

Background

Celiac disease (CD) has a strong genetic component mainly due to HLA DQ2/DQ8 encoding genes. However, a minority of CD patients are DQ2/DQ8-negative. To address this issue, we retrospectively characterized HLA haplotypes in 5,535 subjects at risk of CD (either relatives of CD patients or subjects with CD-like symptoms) referred to our center during a 10-year period.

Methods

We identified loci DQA1/DQB1/DRB1 by sequence-specific oligonucleotide-PCR and sequence-specific primer-PCR; anti-transglutaminase IgA/IgG and anti-endomysium IgA by ELISA and indirect immunofluorescence, respectively.

Results

We diagnosed CD in 666/5,535 individuals, 4.2% of whom were DQ2/DQ8-negative. Interestingly, DQ7 was one of the most abundant haplotypes in all CD patients and significantly more frequent in DQ2/DQ8-negative (38%) than in DQ2/DQ8-positive CD patients (24%) (p<0.05).

Conclusion

Our data lend support to the concept that DQ7 represents an additive or independent CD risk haplotype with respect to DQ2/DQ8 haplotypes but this finding should be verified in other large CD populations.

Diagnosis of gluten related disorders: Celiac disease, wheat allergy and non-celiac gluten sensitivity

Cereal crops and cereal consumption have had a vital role in Mankind’s history. In the recent years gluten ingestion has been linked with a range of clinical disorders. Gluten-related disorders have gradually emerged as an epidemiologically relevant phenomenon with an estimated global prevalence around 5%. Celiac disease, wheat allergy and non-celiac gluten sensitivity represent different gluten-related disorders. Similar clinical manifestations can be observed in these disorders, yet there are peculiar pathogenetic pathways involved in their development. Celiac disease and wheat allergy have been extensively studied, while non-celiac gluten sensitivity is a relatively novel clinical entity, believed to be closely related to other gastrointestinal functional syndromes. The diagnosis of celiac disease and wheat allergy is based on a combination of findings from the patient’s clinical history and specific tests, including serology and duodenal biopsies in case of celiac disease, or laboratory and functional assays for wheat allergy. On the other hand, non-celiac gluten sensitivity is still mainly a diagnosis of exclusion, in the absence of clear-cut diagnostic criteria. A multimodal pragmatic approach combining findings from the clinical history, symptoms, serological and histological tests is required in order to reach an accurate diagnosis. A thorough knowledge of the differences and overlap in clinical presentation among gluten-related disorders, and between them and other gastrointestinal disorders, will help clinicians in the process of differential diagnosis.

Celiac Disease in a Predisposed Subject (HLA-DQ2.5) with Coexisting Graves' Disease

Celiac disease is an intestinal autoimmune disorder, triggered by ingestion of a gluten-containing diet in genetically susceptible individuals. The genetic predisposition is related to human leukocyte antigen (HLA) class II genes, especially HLA-DQ2-positive patients. The prevalence of celiac disease has been estimated to be ~1% in Europe and the USA, but it is rarer and/or underdiagnosed in Asia. We report a case of celiac disease in a predisposed patient, with a HLA-DQ2 heterodimer, and Graves' disease that was treated successfully with a gluten-free diet. A 47-year-old woman complained of persistent chronic diarrhea and weight loss over a 9 month period. Results of all serological tests and stool exams were negative. However, the patient was found to carry the HLA DQ2 heterodimer. Symptoms improved after a gluten-free diet was initiated. The patient has been followed and has suffered no recurrence of symptoms while on the gluten-free diet. An overall diagnosis of celiac disease was made in a genetically predisposed patient (HLA-DQ2 heterodimer) with Graves' disease.

Epigenetic Methodologies for the Study of Celiac Disease

Epigenetic regulation of gene expression is an important event for normal cellular homeostasis. Gene expression may be "switched" on or "turned" off via epigenetic means through adjustments in the architecture of DNA. These structural alterations result from histone posttranslation modifications such as acetylation and methylation on key arginine and lysine residues, or by alterations to DNA methylation. Other known epigenetic mechanisms invoke histone variant exchange or utilize noncoding RNAs (lncRNA/miRNA). Drugs which can target the epigenetic regulatory machinery are currently undergoing clinical trials in a wide variety of autoimmune diseases and cancer. Here we describe RNA isolation and the subsequent Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) methods, post-epigenetic drug treatment, to identify genes, which may be responsive to such epigenetic targeting agents. In addition, we depict a chromatin immunoprecipitation (ChIP) assay to determine the association between chromatin transcription markers and DNA following pretreatment of cell cultures with a histone deacetylase inhibitor (HDi). This assay allows us to determine whether treatment with an HDi dynamically remodels the promoter region of genes, as judged by the differences in the PCR product between our treated and untreated samples. Finally we describe two commonly used methodologies for analyzing DNA methylation. The first, methylation-sensitive high resolution melt analysis (MS-HRM) is used for methylation screening of regions of interest, to identify potential epigenetic "hotspots." The second, quantitative methylation specific PCR (qMSP) is best applied when these hotspots are known, and offers a high-throughput, highly sensitive means of quantifying methylation at specific CpG dinucleotides.

Clinical utility of celiac disease-associated HLA testing

BACKGROUND

Negative predictive value (NPV) of celiac disease (CD)-related human leukocyte antigens (HLA) DQ2 and DQ8 approaches 100 % in individual patients. However, studies evaluating its exclusionary utility in patient groups are lacking.

AIM

We aim to assess the performance of HLA testing when applied to patient groups with varying characteristics and propose evidence-based recommendations for its clinical use.

METHODS

Demographic and clinical information was recorded in patients undergoing HLA testing. Using predetermined criteria, patients were classified as CD, non-CD, or indeterminate. Diagnostic yield of HLA testing was defined as the percentage of patients in whom CD could be excluded based on negative HLA test.

RESULTS

Two hundred and fifty-six patients underwent testing for CD-related HLA DQ2 and DQ8. 102 (100 non-CD, 2 CD) patients tested HLA negative for a 98 % NPV and 39 % diagnostic yield. Diagnostic yield was highest (60 %) in patients with intraepithelial lymphocytosis plus normal IgA tissue transglutaminase antibody (IgA-tTG) and lowest in patients with positive IgA-tTG plus villous atrophy (0 %). CD was diagnosed in two HLA-negative patients, who carried half of DQ2.5 trans genotype.

CONCLUSIONS

Diagnostic yield of CD-related HLA testing varies widely depending on clinical indication. HLA testing is a practical and valuable test for most patients in whom initial evaluation for CD is inconclusive. A negative HLA result usually obviates the need for further celiac testing including endoscopy and gluten challenge. Rarely, in patients reported as HLA negative, half of HLA DQ2.5 (cis or trans) is sufficient for development of CD.

HLA genotyping in pediatric celiac disease patients

Celiac disease (CD) is a chronic inflammatory disease in the small intestine triggered by gluten uptake that occurs in genetically susceptible individuals. HLA-DQ2 protein encoded by HLA-DQA1*05 and DQB1*02 alleles is found in 90-95% of CD patients. All of the remaining patients carry HLA-DQ8 protein encoded by HLA-DQA1*03 and DQB1*03:02 alleles. Specific HLA-DQ genotypes define different risk for CD incidence. Presence of susceptible HLA-DQ genotypes does not predict certain disease development, but their absence makes CD very unlikely, close to 100%. Here we presented for the first time the distribution of HLA-DQ genotypes in the group of pediatric celiac patients from the University Children's Hospital, Belgrade, Serbia and estimated risk for CD development that these genotypes confer. Seventy three celiac disease patients and 62 healthy individuals underwent genotyping for DQA1, DQB alleles and DRB1 allele. 94.5% of patients carried alleles that encode DQ2 protein variant and 2.7% carried alleles that encode DQ8 protein variant. Two patients carried single DQB1*02 allele. No patients were negative for all the alleles predisposing to CD. The highest HLA-DQ genotype risk for CD development was found in group of patients homozygous for DQ2.5 haplotype, followed by the group of heterozygous carriers of DQ2.5 haplotype in combination with DQB1*02 allele within the other haplotype. The lowest risk was observed in carriers of a single copy of DQB1*02 or DQA1*05 allele or other non-predisposing alleles. HLA genotyping, more informative than serological testing commonly used, proved to be a useful diagnostic tool for excluding CD development.

Celiac disease-associated autoimmune hepatitis in childhood: long-term response to treatment

OBJECTIVES

Celiac disease (CD) is common in patients with autoimmune liver disease (AILD); however, the long-term response to treatment of patients with AILDs coexistent with CD has not been explored in detail. The aim of the present study was to analyze the features and the long-term response to immunosuppressive treatment in children with autoimmune hepatitis (AIH) associated with CD.

METHODS

Retrospective and prospective evaluation of patients followed at a single center.

RESULTS

Among 79 patients with AIH, 15 (19%) had CD (9 type 1, 3 type 2, 3 seronegative). In the group of patients with AIH and CD, female sex was significantly more represented than in the group of patients with AIH alone; also, in the former group, diagnosis was made significantly earlier (P < 0.05). All of the 15 patients on a gluten-free diet achieved sustained remission when treated with prednisone and azathioprine or cyclosporine. The mean period of follow-up was 73 months; discontinuation of therapy was attempted in 9 patients while in remission: 4 patients relapsed, 5 (33%) could definitively stop immunosuppressive treatment with a mean period of treatment-free sustained remission of 89 months (range 26-174). In the same period, treatment discontinuation, attempted in 24 of 64 patients with AIH without CD, was successful in 5 patients (8%; P < 0.05).

CONCLUSIONS

Patients with AIH coexisting with CD achieve treatment-free sustained remission in a significantly higher proportion, when compared with patients with AIH without CD, suggesting a possible long-term adjuvant effect of a gluten-free diet.

Human leukocyte antigen DQ2/8 prevalence in non-celiac patients with gastrointestinal diseases

AIM: To investigate the prevalence of human leukocyte antigen (HLA) DQ2/8 alleles in Southern Italians with liver and gastrointestinal (GI) diseases outside of celiac disease.

METHODS: HLA DQ2/8 status was assessed in 443 patients from three ambulatory gastroenterology clinics in Southern Italy (University of Federico II, Naples, Loreto Crispi Hospital, Ruggi D’Aragona Hospital, Salerno). Patients were grouped based on disease status [pre-post transplant liver disease, esophageal/gastric organic and functional diseases, irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD)] and DQ2/8 alleles, which correspond to a celiac disease genetic risk gradient. Subject allele frequencies were compared to healthy Italian controls.

RESULTS: One hundred and ninety-six out of four hundred and forty-three (44.2%) subjects, median age 56 years and 42.6% female, were DQ2/8 positive. When stratifying by disease we found that 86/188 (45.7%) patients with liver disease were HLA DQ2/8 positive, 39/73 (53.4%) with functional upper GI diseases and 19/41 (46.3%) with organic upper GI diseases were positive. Furthermore, 38/105 (36.2%) patients with IBS and 14/36 (38.9%) with IBD were HLA DQ2/8 positive (P = 0.21). Compared to healthy controls those with functional upper GI diseases disorders had a 1.8 times higher odds of DQ2/8 positivity. Those with liver disease had 1.3 times the odds, albeit not statistically significant, of DQ2/8 positivity. Both those with IBS and IBD had a lower odds of DQ2/8 positivity compared to healthy controls.

CONCLUSION: The proportion of individuals HLA DQ2/8 positive is higher in those with liver/upper functional GI disease and lower in IBS/IBD as compared to general population estimates.

Sex differences in coeliac disease risk: a Swedish sibling design study

BACKGROUND

For unknown reasons girls are at an increased risk of coeliac disease compared to boys. However, the observed association might be confounded, since maternal coeliac disease is associated with both an increased risk of the disease in first-degree relatives as well as an increased ratio of girls to boys in offspring.

AIMS

We investigate the effect of sex on the risk of coeliac disease before the age of two years using sibling design.

METHODS

We identified all singleton children (n=792,401) born between 1987 and 1993 in Sweden using the Swedish Medical Birth Registry. Coeliac disease cases (2264) were identified using the Swedish National Inpatient Registry. We applied both conventional population-based Cox regression models and sibling designs modelling the association in sex discordant siblings.

RESULTS

We observed a conclusively increased risk of coeliac disease in girls compared to boys, using both sibling design (hazard ratio 1.67, 95% confidence interval 1.44-1.93) and conventional Cox regression analysis (hazard ratio 1.75, 95% confidence interval 1.61-1.91) that could not be explained by perinatal factors previously associated with the disease.

CONCLUSIONS

We confirm that female sex is causally associated with childhood coeliac disease, but the reasons remains unknown.

HLA-DQA1 and HLA-DQB1 in Celiac disease predisposition: practical implications of the HLA molecular typing

Celiac disease (CD) is a multifactorial disorder with an estimated prevalence in Europe and USA of 1:100 and a female:male ratio of approximately 2:1. The disorder has a multifactorial etiology in which the triggering environmental factor, the gluten, and the main genetic factors, Human Leukocyte Antigen (HLA)-DQA1 and HLA-DQB1 loci, are well known. About 90-95% of CD patients carry DQ2.5 heterodimers, encoded by DQA1*05 and DQB1*02 alleles both in cis or in trans configuration, and DQ8 molecules, encoded by DQB1*03:02 generally in combination with DQA1*03 variant. Less frequently, CD occurs in individuals positive for the DQ2.x heterodimers (DQA1≠*05 and DQB1*02) and very rarely in patients negative for these DQ predisposing markers. HLA molecular typing for Celiac disease is, therefore, a genetic test with a negative predictive value. Nevertheless, it is an important tool able to discriminate individuals genetically susceptible to CD, especially in at-risk groups such as first-degree relatives (parents, siblings and offspring) of patients and in presence of autoimmune conditions (type 1 diabetes, thyroiditis, multiple sclerosis) or specific genetic disorders (Down, Turner or Williams syndromes).

Revisiting the risk of celiac disease in children born small for gestational age: a sibling design perspective

OBJECTIVE

An association between small for gestational age (SGA) and risk for celiac disease (CD) in childhood has previously been reported. However, this association may reflect residual confounding by genetic or environmental factors. For example, presence of subclinical CD in the mother might be a common cause of both SGA and CD in the offspring. We investigate whether SGA is causally associated with CD before age six years by applying both conventional population-based regression models and sibling analysis that investigates the association in siblings discordant for SGA.

MATERIAL AND METHODS

Using the Swedish Medical Birth Registry, we identified all singleton children born in Sweden during 1987-1993 (792,401). Of these we included 681,954 children in the study and identified 2641 cases of CD using the Swedish National In-Hospital Registry. We applied both conventional Cox regression analysis and a quasi-experimental sibling design that to some extent simulates a counterfactual situation of exposure, reducing possible confounding effects of genetic and shared environmental factors.

RESULTS

We identified an increased risk of CD in both boys (hazard ratio (HR) 1.70, 95% confidence interval (CI) 1.25-2.32) and girls (HR 1.30, 95% CI 0.99-1.70) using conventional Cox regression models. Using sibling analysis, the association between SGA and CD was confirmed in boys (HR 4.23, 95% CI 1.19-15.04) but not in girls (HR 1.00, 95% CI 0.45-2.20).

CONCLUSIONS

Our results support a causal association between SGA and CD risk in boys but not in girls, although the mechanisms underlying this difference are still unclear.

Parent-of-origin effects of FAS and PDLIM1 in attention-deficit/hyperactivity disorder

BACKGROUND

Previous studies have suggested that there may be a parent-of-origin effect for attention-deficit/hyperactivity disorder(ADHD) candidate genes. The objective of the present study was to investigate parent-of-origin effects using a genome-wide association analysis of the International Multicentre ADHD Genetics (IMAGE) study sample.

METHODS

Family-based association analysis for ADHD using 846 ADHD probands and their parents was performed using the PLINK program, and parent-of-origin effects were studied using a Z score for the difference in paternal versus maternal odds ratios.

RESULTS

We identified 44 single nucleotide polymorphisms (SNPs) showing parent-of-origin effects at a significance level of p < 0.001. The most significant SNP, rs7614907, is at position 3q13.33 in the CDGAP gene (p = 0.000064 for parent-of-origin effect). Furthermore, 2 genes (FAS and PDLIM1) showed moderate parent-of-origin effects (p = 0.00086 for rs9658691 and p = 0.00077 for rs11188249) and strong maternal transmission (p = 0.000059 for rs9658691 and p = 0.0000068 for rs11188249). In addition, ZNF775 showed a moderate parent-of-origin effect (p = 0.00036 for rs7790549) and strong paternal transmission (p = 0.000041 for rs7790549).

LIMITATIONS

We only had 1 sample available for analysis.

CONCLUSION

These results suggest several genes or regions with moderate parent-of-origin effects, and these findings will serve as a resource for replication in other populations to elucidate the potential role of these genetic variants in ADHD.

Recent advances in celiac disease

Celiac disease now affects about one person in a hundred in Europe and North America. In this review, we consider a number of important and exciting recent developments, such as clinical associations, HLA-DQ2 and HLA-DQ8 predispositions, the concept of potential celiac disease, the use of new imaging/endoscopy techniques, and the development of refractory disease. This review will be of use to all internists, pediatricians and gastroenterologists.

Recent advances in celiac disease

Celiac disease now affects about one person in a hundred in Europe and North America. In this review, we consider a number of important and exciting recent developments, such as clinical associations, HLA-DQ2 and HLA-DQ8 predispositions, the concept of potential celiac disease, the use of new imaging/endoscopy techniques, and the development of refractory disease. This review will be of use to all internists, pediatricians and gastroenterologists.

Celiac disease: an underappreciated issue in women&#x2019;s health

Celiac disease (CD) is an immune-mediated enteropathy that is secondary to gluten ingestion and classically associated with gastrointestinal symptoms. Diagnosis is based on serology and confirmatory duodenal biopsy, and the only treatment is lifelong avoidance of gluten. CD has been increasingly recognized to encompass a wide variety of manifestations that are relevant to women&#x2019;s health, including infertility, adverse pregnancy outcomes and reduced BMD. Currently, CD is underdiagnosed, largely owing to lack of recognition of the diverse manifestations by general practitioners. Increased awareness of the clinical spectrum of this disease, as well as targeted testing in at-risk individuals (including women with unexplained infertility and previous adverse pregnancy outcomes, and in specific populations with reduced BMD) is greatly needed in order to improve rates of diagnosis.

HLA-G 14 bp deletion/insertion polymorphism in celiac disease

OBJECTIVES

Nonclassical major histocompatibility class I HLA-G antigen is a tolerogenic molecule that inhibits lytic activity of natural killer (NK) cells and cytotoxic T lymphocytes. Because of its immunomodulatory and tolerogenic properties, HLA-G molecules may have a role in celiac disease (CD). We analyzed the HLA-G 14 bp deletion/insertion polymorphism, known to have a functional effect on mRNA stability, in a group of 522 CD patients, stratified for the presence of HLA-DQ2 genotype, and 400 healthy individuals to evaluate the possible effect of the polymorphism on the risk to develop the disease.

METHODS

HLA-G 14 bp deletion/insertion polymorphism (rs1704) was detected by polymerase chain reaction and double-checked by direct sequencing.

RESULTS

The 14 bp inserted (I) allele and the homozygous I/I genotype were significantly more frequent in CD patients than in healthy controls. The presence of I allele was associated with an increased risk of CD (OR 1.35) and the effect of I allele was consistent with a recessive genetic model (P<0.001).

CONCLUSIONS

Our results also indicate that the effect of the HLA-G D/I polymorphism is restricted for HLA-DQ2, and not simply due to the presence of linkage disequilibrium with the major known risk factor; moreover we found that the presence of the I allele confers an increased risk of CD in addition to the risk conferred by HLA-DQ2 alone and that subjects that carry both DQ2 and HLA-G I alleles have an increased risk of CD than subjects that carry DQ2 but not the I allele.

Coeliac disease and body mass index: a study of two Swedish general population-based registers

OBJECTIVE

To examine the relationship between body mass index (BMI) and an inpatient diagnosis of coeliac disease (CD) in two independent Swedish national registers.

MATERIAL AND METHODS

Study 1: Cohort study of women. The relationship between (pre-pregnancy) BMI and CD in pregnant women was evaluated (174 undiagnosed CD (at time of pregnancy), 550 diagnosed CD, 787,986 without a diagnosis of CD). The association between BMI and undiagnosed CD was estimated by Cox regression. Study 2: Case-control study of men. The relationship between BMI and CD in male conscripts was evaluated (70 undiagnosed CD, 1,047 diagnosed CD and 6,887 without a diagnosis of CD). The association between BMI and undiagnosed CD was estimated by logistic regression. Prevalence of underweight, normal weight and overweight was compared between diagnosed CD, undiagnosed CD and no diagnosis of CD.

RESULTS

The prevalence of underweight (BMI <18.5) in women was: reference individual: 5.2%; undiagnosed CD: 16.7% and prior diagnosis of CD: 6.4%. In men, the corresponding figures were 6.5%; 14.3% and 9.8%, respectively. Underweight was associated with undiagnosed CD (future diagnosis of CD) in both women (hazard ration (HR) = 2.5; 95% CI = 1.6-3.7) and men (odds ratio (OR) = 2.4; 95% CI = 1.2-4.9). In women, overweight was negatively associated with undiagnosed CD (HR = 0.6; 95% CI = 0.4-0.9), but not in men (OR = 1.1; 95% CI = 0.6-2.2). 9.2% of women with undiagnosed CD and 14.3% of men with undiagnosed CD were overweight.

CONCLUSIONS

Underweight individuals are at increased risk of having undiagnosed CD. However, overweight does not rule out CD.

Recent advances in coeliac disease

PURPOSE OF REVIEW

Worldwide awareness of coeliac disease in all ages continues to grow. This article aims to summarize critically the recent research advances in coeliac disease.

RECENT FINDINGS

Large multicentre studies have provided further evidence of the role of environmental and nonhuman leucocyte antigen genetic factors in coeliac disease. Siblings of coeliac patients carry a high risk, but those found to have negative coeliac serology are very unlikely to develop the disease. Advances in the efficacy of serological antibody testing potentiate the possibility of future accurate screening programmes in the community. Adherence to a gluten-free diet remains paramount as the recognition of coeliac related complications increases.

SUMMARY

Despite the encouraging progress that has taken place in our genetic and immunological knowledge of coeliac disease, early introduction of a gluten-free diet remains the cornerstone of treatment. Alternatives, however, aimed at altering the toxicity of cereal proteins are now looking more promising.

HLA-DQ and risk gradient for celiac disease

Celiac disease (CD) is a rare example of multifactorial disorder in which a genetic test is of great clinical relevance, as the disease rarely develops in the absence of specific HLA alleles. We typed DR-DQ genes in 437 Italian children with celiac disease, 834 first-degree relatives, and 551 controls. Of patients, 91% carried DQ2 and/or DQ8 heterodimers, 6% only had beta2 chain, 2% was alpha5 positive, and four were DQ2/DQ8/beta2/alpha5 negative. Only the presence of alpha5 resulted negatively associated to disease (p = 2 x 10(-4)), whereas we confirmed the effect of the beta half of DQ2 dimer on CD predisposition (p = 4 x 10(-12)). Considering 1:100 disease prevalence, we obtained a risk gradient ranging from 1:7 for DQ2 and DQ8 individuals down to 1:2518 for subjects lacking all predisposing factors. The DQB1*02 and DQB1*0302 concurrence (p = 9 x 10(-4)), besides the DQB1*02/*02 homozygosity, had an additional role in disease genetic determination. The CD prevalence rose to 17.6% in sisters, 10.8% in brothers, and 3.4% in parents. In the three groups, the subjects carrying high-risk HLA molecules were 57%, 71%, and 58%; among them, 29%, 15%, and 6% respectively had CD. Those siblings and parents with no susceptible factors were not affected. These findings indicate the impact of the HLA test for CD in clinical practice.