Association of human leucocyte-DR and DQ antigens in coeliac disease: a family study

Human Leukocyte Antigen DQ (HLA-DQ) genotypes and haplotypes and their association with phenotype in patients with celiac disease in India

Background and Aim

Human Leukocyte Antigen DQ (HLA‐DQ) genotypes play a permissive role in the genesis of celiac disease (CeD). In this case–control study, we used next‐generation sequencing to determine HLA‐DQA1 and ~DQB1 genotypes and haplotypes associated with CeD in Indian patients.

Methods

HLA‐DQA1 and ~DQB1 loci were amplified, using long‐range polymerase chain reaction (PCR), from DNA of 259 patients with symptomatic CeD (160 typical and 99 atypical), 45 asymptomatic CeD, 96 potential CeD, and 300 healthy adults. Amplicons were fragmented and sequenced on the Illumina platform, and alleles and haplotypes were assigned by matching against the HLA‐international ImMunoGeneTics (IMGT) database.

Results

HLA‐DQA1*05:01 (odds ratio [OR] 8.39, 95% confidence interval [CI] 5.64–12.47) and HLA‐DQB1*02:01 (OR 8.59, 95% CI 5.75–12.83) were the genotypes that showed a risk association with symptomatic CeD. Among the haplotypes, HLA‐DQA1*05:01 ~ HLA‐DQB1*02:01 (OR 8.56, 95% CI 5.67–13.19) showed a strong risk association with symptomatic CeD. When comparing symptomatic CeD with subclinical forms (asymptomatic and potential) CeD, HLA‐DQA1*05:01 ~ HLA‐DQB1*02:01 (OR 2.34, 95% CI 1.61–3.43) was significantly associated with risk of symptomatic disease. The strength of association between the HLA‐DQA1*05:01 ~ HLA‐DQB1*02:01 haplotype and the CeD phenotype showed a gradient in the order typical > atypical > asymptomatic > potential CeD. Genotypes consistent with expression of HLA DQ2 and/or 8 were noted in 128 (80%) typical, 73 atypical (74%), 27 (60%) asymptomatic, and 52 (54%) potential CeD participants.

Conclusion

HLA‐DQA1*05:01 ~ HLA‐DQB1*02:01 (haplotype DQ2.5) showed a very strong risk association with symptomatic CeD in Indian patients. The strength of association showed a gradient of increase from potential to typical CeD, coinciding with a phenotypic change in the celiac iceberg.

Cross-Talk Between Gluten, Intestinal Microbiota and Intestinal Mucosa in Celiac Disease: Recent Advances and Basis of Autoimmunity

Celiac disease (CD) is an autoimmune disorder of the small intestine, caused by gluten induced inflammation in some individuals susceptible to genetic and environmental influences. To date, pathophysiology of CD in relation to intestinal microbiota is not known well. This review relies on contribution of intestinal microbiome and oral microbiome in pathogenesis of CD based on their interactions with gluten, thereby highlighting the role of upper gastrointestinal microbiota. It has been hypothesized that CD might be triggered by additive effects of immunotoxic gluten peptides and intestinal dysbiosis (microbial imbalance) in the people with or without genetic susceptibilities, where antibiotics may be deriving dysbiotic agents. In contrast to the intestinal dysbiosis, genetic factors even seem secondary in disease outcome thus suggesting the importance of interaction between microbes and dietary factors in immune regulation at intestinal mucosa. Moreover, association of imbalanced counts of some commensal microbes in intestine of CD patients suggests the scope for probiotic therapies. Lactobacilli and specific intestinal and oral bacteria are potent source of gluten degrading enzymes (glutenases) that may contribute to commercialization of a novel glutenase therapy. In this review, we shall discuss advantages and disadvantages of food based therapies along with probiotic therapies where probiotic therapies are expected to emerge as the safest biotherapies among other in-process therapies. In addition, this review emphasizes on differential targets of probiotics that make them suitable to manage CD as along with glutenase activity, they also exhibit immunomodulatory and intestinal microbiome modulatory properties.

Morphologic Spectrum of Duodenal Biopsies in Malabsorption: A Study from Southern India

INTRODUCTION

Duodenal endoscopic biopsy is a common investigation for various non-neoplastic conditions. Malabsorption is a common indication for duodenal biopsy in our setting.

AIM

Our study was undertaken to study the morphologic spectrum of non-neoplastic conditions of duodenum emphasizing on Intraepithelial Lymphocytes (IELs) and to have a clinico-pathologic correlation.

MATERIALS AND METHODS

This was a prospective descriptive study. Duodenal biopsies from 101 patients with symptoms of malabsorption were studied according to inclusion and exclusion criteria. Informed written consent was taken. Clinical, laboratory, endoscopic, and serological parameters were collected wherever available. Histomorphological parameters were studied on Haematoxylin and Eosin (H&E) stained sections. Intraepithelial lymphocyte counts were done on CD3, CD4 and CD8 Immunohistochemical (IHC) stained sections and correlated.

RESULTS

We studied 101 duodenal biopsies. Our spectrum included 16 patients of celiac disease (CD) (15.8%), 15 autoimmune duodenitis (14%), 13 nutritional deficiency associated duodenitis (12.8%), five infectious duodenitis (5%) and 41 patients of non-specific duodenitis (40.6%) and 10.9% miscellaneous causes of duodenitis. Villous crypt architecture, IEL counts; villous tip IEL counts were statistically significant between CD and other disease groups.

CONCLUSION

A constellation of clinical, serological, endoscopic and histopathologic features is essential in diagnosing CD and autoimmune duodenitis. Biopsy is also a useful tool in diagnosing infectious duodenitis that are missed in other investigations.

Prevalence of Adult Celiac Disease in India: Regional Variations and Associations

OBJECTIVES

Although celiac disease (CeD) affects 1% of people in the northern part of India, it is believed to be uncommon in the southern and northeastern parts because of significant differences in dietary pattern and ethnicity. We estimated the prevalence of CeD in these three populations. In a subset, we also investigated differences in the prevalence of HLA-DQ 2/8 allelotype and dietary grain consumption.

METHODS

A total of 23,331 healthy adults were sampled from three regions of India-northern (n=6207), northeastern (n=8149), and southern (n=8973)-and screened for CeD using IgA anti-tissue transglutaminase antibody. Positive tests were reconfirmed using a second ELISA. CeD was diagnosed if the second test was positive and these participants were further investigated. A subsample of participants was tested for HLA-DQ2/-DQ8 and underwent detailed dietary evaluation.

RESULTS

Age-adjusted prevalence of celiac autoantibodies was 1.23% in northern, 0.87% in northeastern, and 0.10% in southern India (P<0.0001). Prevalence of CeD and latent CeD, respectively, was 8.53/1,000 and 3.70/1,000 in northern, 4.66/1,000 and 3.92/1,000 in northeastern, and 0.11/1,000 and 1.22/1,000 in the southern part. The population prevalence of genes determining HLA-DQ2 and/or -DQ8 expression was 38.1% in northern, 31.4% in northeastern, and 36.4% in southern India. Mean daily wheat intake was highest in northern (455 g) compared with northeastern (37 g) or southern part (25 g), whereas daily rice intake showed an inverse pattern.

CONCLUSIONS

CeD and latent CeD were most prevalent in northern India and were the least in southern India. The prevalence correlated with wheat intake and did not reflect differences in the genetic background.

Issues associated with the emergence of coeliac disease in the Asia–Pacific region: a working party report of the World Gastroenterology Organization and the Asian Pacific Association of Gastroenterology

BACKGROUND AND AIM

Once thought to be uncommon in Asia, coeliac disease (CD) is now being increasingly recognized in Asia–Pacific region. In many Asian nations, CD is still considered to be either nonexistent or very rare. In recognition of such heterogeneity of knowledge and awareness, the World Gastroenterology Organization and the Asian Pacific Association of Gastroenterology commissioned a working party to address the key issues in emergence of CD in Asia.

METHODS

A working group consisting of members from Asia–Pacific region, Europe, North America, and South America reviewed relevant existing literature with focus on those issues specific to Asia–Pacific region both in terms of what exists and what needs to be done.

RESULTS

The working group identified the gaps in epidemiology, diagnosis, and management of CD in Asian–Pacific region and recommended the following: to establish prevalence of CD across region, increase in awareness about CD among physicians and patients, and recognition of atypical manifestations of CD. The challenges such as variability in performance of serological tests, lack of population-specific cut-offs values for a positive test, need for expert dietitians for proper counseling and supervision of patients, need for gluten-free infrastructure in food supply and creation of patient advocacy organizations were also emphasized.

CONCLUSIONS

Although absolute number of patients with CD at present is not very large, this number is expected to increase over the next few years or decades. It is thus appropriate that medical community across the Asia–Pacific region define extent of problem and get prepared to handle impending epidemic of CD.

Prevalence of celiac disease in the northern part of India: a community based study

BACKGROUND AND AIM

While celiac disease is estimated to affect about 1% of the world's population, it is thought to be uncommon not only in India but in Asia also. There is a lack of studies on the prevalence of celiac disease from Asian nations. The aim of the present study was to estimate the prevalence of celiac disease in the community.

METHODS

In a cross sectional study, we estimated the prevalence of celiac disease in urban and rural populations in the National Capital Region, Delhi, India. A structured questionnaire was administered, by door-to-door visits, to all participants to collect socio-demographic data and to screen for features of celiac disease, namely chronic or recurrent diarrhea and, anemia. In children, additional features, namely short stature (linear height below 5th percentile for age) and failure to thrive/gain weight were also used. All respondents who were screen positive (any one of above) and 10% of screen negative individuals were called for serological testing, which is anti-tissue transglutaminase antibody. All serologically positive respondents were invited to undergo further evaluation including endoscopic biopsy. Celiac disease was diagnosed on the basis of a positive serology, the presence of villous atrophy and/or response to gluten free diet.

RESULT

Among 12,573 contacted, 10,488 (83.4%) (50.6% male) agreed to participate. Based on screening, 5622 (53.6%) participants were screen positive. Of all those screen positive, 2167 (38.5%) agreed for serological testing; additionally 712 (14%) negatives were also tested. The overall sero-prevalence of celiac disease was 1.44% (95% confidence interval [CI] 1.22 1.69) and the overall prevalence of celiac disease was 1.04% (95% CI 0.85 1.25).

CONCLUSION

The prevalence of celiac disease in this north Indian community is 1 in 96. Celiac disease is more common than is recognized in India.

Prevalence, human leukocyte antigen typing and strategy for screening among Asian first-degree relatives of children with celiac disease

BACKGROUND AND AIM

Data on prevalence, human leukocyte antigen (HLA) typing and small bowel histology among first-degree relatives of subjects with celiac disease (CD) is scarce. This prospective study evaluated the prevalence and role of HLA DQ2/8 testing in screening of first-degree relatives of children with CD.

METHODS

Thirty confirmed children with CD and 91/94 first-degree relatives (parents and siblings) were enrolled. HLA DQ2/8 testing was carried out in all index CD cases. Clinical evaluation with a questionnaire, total serum immunoglobulin A (IgA), human IgA-tissue transglutaminase (IgA-tTGA) and HLA DQ2/8 testing was carried out in all first-degree relatives. Subjects who were positive for IgA-tTGA were recommended endoscopic duodenal biopsy to document histological changes of CD.

RESULTS

Nine first-degree relatives were positive for IgA-tTGA, seven underwent duodenal biopsy and four subjects had Marsh IIIa changes suggestive of CD. The prevalence of histologically confirmed CD in first-degree relatives was 4.4%. The prevalence of potential CD was 9.8%. IgA-tTGA-positive subjects (4/9) were significantly more often symptomatic than IgA-tTGA-negative first-degree relatives (2/82). Twenty-nine (96.6%) index cases of CD and all IgA-tTGA-positive first-degree relatives were positive for HLA DQ2. None of the index CD cases or first-degree relatives were HLA DQ8-positive. A total of 85% of the first-degree relatives were positive for HLA DQ2 and thus at risk of developing CD.

CONCLUSIONS

In this first Asian study on a limited number of families of children with CD, 4.4% of the first-degree relatives had CD. Only 15% of the first-degree relatives were negative for HLA DQ2/DQ8. Initial evaluation with HLA and serology followed by only serial serology in HLA-positive relatives is recommended.

Indian task force for celiac disease: Current status

There are limited data on celiac disease (CD) from India. The limited knowledge about CD in India might be attributed to several factors. The first meeting of the Indian Task Force for Celiac Disease was held in the Asian Institute of Gastroenterology, Hyderabad, India in December 2008. The objectives of the meeting were to focus research on prevalence of CD in the wheat-eating Northern vs the rice-eating Southern Indian population, low-budget serological assays to study the underprivileged population, to involve other medical subspecialties in CD, to suggest proper legislation regarding wheat food labeling, and to organize affordable food substitutes for patients with celiac disease.

Prevalence of celiac disease in Shiraz, southern Iran

BACKGROUND/AIM

This study was performed to evaluate the prevalence of celiac disease (CD) in Shiraz, southern Iran.

MATERIALS AND METHODS

Serum samples were collected from 1440 persons (age range = 20-83 years, mean age = 45.4 years) in 2004 and screened for endomysial and tissue transglutaminase antibodies. A questionnaire was completed for all subjects in relation to gastrointestinal (GI) symptoms and cases with positive serology were requested to undergo small-bowel biopsy.

RESULTS

Seven cases (0.5%) were positive for IgA anti-tissue transglutaminase (anti-tTG), and only two (0.14%) were positive for IgA anti-endomysial antibody (anti-EMA), both of whom had highly positive anti-tTg levels (40.4 and 48.0 IU/l). The major clinical symptoms of CD, such as recurrent abdominal pain and change in bowel habits were present in all patients with positive anti-tTG assays. Only five subjects with positive serology agreed to undergo upper GI endoscopy and duodenal biopsy. Three of these cases were reported with Marsh I histologic findings, while in the two cases with positive serologic anti-EMA, more advanced forms of CD were present.

CONCLUSION

The prevalence of CD in apparently healthy adults was lower than the reported series from northern parts of the country; therefore, we suggest a more long-term follow-up study in high-risk groups, especially in the apparently healthy subjects in our region.

Effect of a gluten-free diet on growth and small-bowel histology in children with celiac disease in India

BACKGROUND AND AIM

Follow-up studies on growth and histological recovery of children with celiac disease (CD) while on a gluten-free diet (GFD) are lacking from Asia. We therefore assessed the effects of this diet.

METHODS

Forty-two children with CD were enrolled. Weight and height were expressed as weight for height (WfH) and height standard deviation scores (HSDS), respectively. Twenty-five children had repeated duodenal biopsies after 1-2 years and 14 had a third biopsy after 3-7 years of GFD. Compliance was checked by regular interview and IgA antiendomysial antibody estimation (EMA).

RESULTS

At diagnosis (n = 25), mean HSDS was -3.3 +/- 1.6 with 76% having a HSDS of <-2; 60% were undernourished (WfH mean 81.6 +/- 5.7). Over a mean follow up of 3.7 years, HSDS improved to -1.3 +/- 1.7 and 84% cases achieved normal nutrition. Mean height velocity was 13.9 cm during first year and 5.6 cm in subsequent years. Small-bowel biopsies at diagnosis showed subtotal villous atrophy (Marsh IIIb) in 18 (72%) and partial villous atrophy (Marsh IIIa) in seven (28%) patients. Repeat biopsy at 1-2 years showed shift from subtotal to partial villous atrophy in 94% (n = 17/18) and normalization in one patient. In patients with Marsh IIIa improvement of partial villous atrophy was observed in all. Immunoglobulin A endomysial antibody was negative in 81%. Repeat biopsies at 5 years of GFD showed improvement to Marsh I-II, but none normalized.

CONCLUSION

The majority of children with CD show normalization of nutrition and growth after GFD. Small-bowel histology improves markedly but does not normalize even after 5 years of GFD.

Celiac disease in the developing countries: A new and challenging public health problem

In the past, celiac disease was believed to be a chronic enteropathy, almost exclusively affecting people of European origin. The availability of new, simple, very sensitive and specific serological tests (anti-gliadin, anti-endomysium and anti-transglutaminase antibody assays) have shown that celiac disease is common not only in Europe and in people of European ancestry but also in the developing countries where the major staple diet is wheat (Southern Asia, the Middle East, North West and East Africa, South America), both in the general population and in the groups at risk. Gluten intolerance thus appears to be a widespread public health problem and an increased level of awareness and clinical suspicion are needed in the New World where physicians must learn to recognize the variable clinical presentations (classical, atypical and silent forms) of celiac disease. In the developing countries, both serological screening in the general population and serological testing in groups at risk are necessary for an early identification of celiac patients. The gluten-free diet poses a challenging public health problem in the developing countries, especially since commercial gluten-free products are not available.

Clinical features of celiac disease in Indian children: are they different from the West?

OBJECTIVE

This study was designed to prospectively evaluate the clinical features of celiac disease (CD) in a large group of Indian children and to compare them with those from the West.

PATIENTS AND METHODS

Over a period of 5 years, a total of 549 children (< or = 14 years) with a clinical suspicion of CD were evaluated. Their detailed clinical features, investigations, and follow-up data were recorded. Complete hemogram, endoscopic duodenal biopsy, and celiac serology were done in all of the cases. Celiac disease was diagnosed on the basis of modified European Society of Paediatric Gastroenterology, Hepatology and Nutrition criteria.

RESULTS

Celiac disease was diagnosed in 300 children; 39 were excluded because of lack of follow-up or poor response to gluten-free diet. The remaining 210 had normal villous architecture and served as controls. The mean (+/- standard deviation) age of children with CD was 6.7 +/- 3 years, and the mean duration of symptoms was 3.5 +/- 2.5 years. The majority (84%) presented with diarrhea; other features were failure to thrive in 91%, anemia in 84%, wasting in 87%, and stunting in 60% of cases. Among the serological tests, the best results were obtained with tissue transglutaminase. On follow-up (19.4 +/- 15.5 months), symptoms subsided in all cases of CD with a significant weight and height gain.

CONCLUSIONS

Indian children with CD present late, with a significant delay in diagnosis. The majority presents with classic symptoms of diarrhea, failure to thrive, and anemia. There is a need for increasing awareness to pick up the atypical forms of the disease.

Diagnosis of celiac disease

Celiac disease is an immune mediated enteropathy initiated by ingestion of gluten, in genetically susceptible individuals. With changing epidemiology, celiac disease initially thought to affect only Europeans, has been increasingly reported from other parts of the world including India. However, its true prevalence in India is still not known, as the diagnosis is being missed. The gold standards for diagnosis have been characteristic small intestinal mucosal changes on gluten and a full clinical remission on its removal from the diet. Presence of serological antibodies, which disappear on gluten free diet further confirms the diagnosis. The understanding of the histopathology of celiac disease has changed over the years. The small bowel mucosal lesion of celiac disease is an evolutionary process with normal mucosal architecture and an increase in intraepithelial lymphocytes at one end of the spectrum and classical flat mucosa at the other. In the Indian subcontinent celiac disease has a heterogeneous histological presentation and the diagnosis may be missed if it is based only on severe mucosal changes or the serology is not considered when moderate or mild mucosal changes are present. The last two decades have shown that antiendomysical (Anti EMA) and anti tissue transglutaminase antibodies (anti-tTGA) have a sensitivity and specificity of more than 95% to diagnose celiac disease. Anti EMA tests being operator dependent are more liable to errors and anti- tTGA may be preferred for large scale screening. However, the different source of tTGA antigen, varied techniques of production and the use of arbitrary units by different commercial kits can influence the diagnostic accuracy of the anti-tTGA assay. There is a strong genetic association of celiac disease with HLA-DQ2 or DQ8. The presence of HLA-DQ2 hetrodimer in more than 97% of a group of North Indian patients with celiac disease indicates that this population has a similar genetic risk for the disease. HLA DQ2 typing can be used for ruling out celiac disease where the diagnosis is equivocal as it has a negative predictive value of greater than 95%. Given the protean clinical manifestation and the heterogeneous histology a standard algorithm for diagnosis of celiac disease is important.

Celiac disease with mild to moderate histologic changes is a common cause of chronic diarrhea in Indian children

OBJECTIVES

In developed countries, small bowel histology in coeliac disease is a spectrum, ranging from normal with increased intraepithelial lymphocytes to the classic flat mucosa. In developing countries, mild to moderate enteropathies in children with chronic diarrhea and growth failure are assumed to be caused by tropical sprue, persistent infections, or malnutrition with bacterial overgrowth. We report the prevalence and histology of coeliac disease in children with chronic diarrhea at a tertiary referral hospital in North India.

METHODS

Two hundred fifty-nine children with symptoms indicating coeliac disease attended the All India Institute of Medical Sciences. Histology was graded after a modified Marsh classification. Serum immunoglobulin A anti-endomysial antibodies (AEA) were assayed using indirect immunofluorescence. Subjects with abnormal histology and positive AEA were put on a gluten free diet (GFD). Coeliac disease was diagnosed on small intestinal biopsy changes and a clinical response to a GFD.

RESULTS

Severe enteropathies were present in 63 (24%) subjects, and 58 (92%) responded to a GFD. Sixty-six (25%) had moderate histologic changes, 61 responding to a GFD. AEA was positive in 56 of 63 patients with severe and 65 of 66 with moderate enteropathies. Fifty-seven children had mild enteropathies, and 19 of 20 with positive AEA responded clinically to a GFD.

CONCLUSIONS

Coeliac disease is more common than previously believed. It presents a variable histology, and diagnoses may be missed or delayed if based only on severe enteropathies. Serology is a useful adjunct to diagnosis, and diagnostic criteria need to be developed appropriately for coeliac disease in developing countries despite limited facilities.

Coeliac disease in developing countries: Middle East, India and North Africa

Following the application of simple serological tests for the diagnosis of coeliac disease (CD) in the 1980s, it gradually became clear that the prevalence of CD in different countries in the Middle East, North Africa and India is almost the same as that in Western countries. The prevalence of CD in at-risk populations in these regions is reported to range between 3 and 20% and the prevalence in people with type 1 diabetes is approximately 3-5%. Clinical manifestations of CD vary markedly with age, the duration and the extent of disease. Clinical studies showed that presentation with non-specific symptoms or no symptoms is as common in the Middle East as it is in Europe. Wheat has been the major staple food in these regions for many centuries and it is possible that the continuous and high level of exposure to wheat proteins has induced some degree of immune tolerance, leading to milder symptoms, which are misdiagnosed as irritable bowel syndrome or unexplained gastrointestinal disorders. A high index of suspicion for CD should be maintained in all developing countries for patients who present with chronic diarrhoea or iron deficiency anaemia. The best method for diagnosing CD in patients with diarrhoea is the panel of coeliac serological tests followed by small-bowel biopsy. In the absence of supplies for a gluten-free diet in Middle Eastern countries, maintaining this diet represents a real challenge to both patients and clinicians.

Coeliac disease in South Asians resident in Britain: comparison with white Caucasian coeliac patients

BACKGROUND

The catchment population of our hospital is ethnically diverse and we have seen a number of patients of South Asian origin with coeliac disease. We have suspected that there are differences compared with white Caucasian coeliacs, especially with respect to iron-deficiency anaemia and vitamin D deficiency at presentation.

AIMS

To compare the clinical and laboratory features of South Asian adult coeliac patients with adult white Caucasian coeliacs.

METHODS

We reviewed the notes of patients attending the adult coeliac clinic over the past 10 years. All patients were older than 16 years at diagnosis. There were 40 South Asians and 90 white Caucasians. Symptoms, haematology, biochemistry, endomysial antibody status, HLA alleles and small bowel histology at presentation were compared between the two racial groups.

RESULTS

There were significant differences between the racial groups. South Asians were younger at presentation than the Caucasian patients (mean age 27 years compared with 47 years respectively, P<0.0001); they were less likely to have 'irritable bowel syndrome' symptoms (P<0.01), but more likely to have features of vitamin D deficiency (P<0.03). Their haemoglobin (P<0.05), mean cell volume (P<0.0004), serum iron (P<0.01), transferrin saturation (P<0.05), serum 1,25-dihydroxyvitamin D3 (P<0.002), and levels were lower, while serum alkaline phosphatase levels were higher (P<0.04) than in white Caucasian coeliac patients. There were no differences with respect to serum folate, vitamin B12, serum calcium, alanine aminotransferase and small bowel histology. IgA class endomysial antibody positivity was similar in the two groups (88.5% for South Asians compared with 73.5% for white Caucasians). White Caucasian patients were significantly more likely to be DQ2-positive than the South Asian patients (97.2% compared with 83.3%, P=0.02).

CONCLUSION

South Asians with coeliac disease are less likely to present with 'irritable bowel syndrome' symptoms, but more likely to have features of vitamin D deficiency and iron deficiency, and have a higher alkaline phosphatase than white Caucasians. The differences in HLA alleles seen in South Asians with coeliac disease compared with white Caucasian patients suggests that among the South Asians, non-HLA regions may play a stronger role in disease susceptibility and presentation.

Genomewide search and association studies in a Finnish celiac disease population: Identification of a novel locus and replication of the HLA and CTLA4 loci

It has been reported that celiac disease (CD) is strongly associated with the HLA-DQ2 alleles DQA1*0501 and DQB1*0201. However, this association only accounts for a portion of the genetic component of CD. Several non-HLA loci and candidate genes that potentially contribute to CD susceptibility have been reported, but have not been confirmed. The aim of this study was to identify loci that contribute to disease susceptibility in a CD population from Finland. We performed a genomewide linkage scan and identified two regions of significant linkage to CD (6p and 2q23-32) and one region of suggestive linkage (10p). We also performed targeted typing and analyses that replicated the associations of the HLA and CTLA4 loci.

The global village of celiac disease

In the last years our knowledge on epidemiology of celiac disease has increased: there is a wide spectrum of its clinical presentation (classical, atypical, silent and latent forms of celiac disease), and of its pathological mucosal intestinal features, which range from early and mild pictures to severe villous atrophy (Marsh stages). In addition, a strong genetic component, associated with the susceptibility to the disease (HLA and non HLA genes), has been found. This knowledge, together with the availability of new high sensitive and specific serological tests (antigliadin, antiendomysium and antitransglutaminase antibodies), has led us to the realization that celiac disease is the most common food intolerance in the world, involving genetically predisposed individuals consuming gluten-containing cereals in their diet. So, today it is well known that celiac disease is a common disorder not only in Europe but also in populations of European ancestry (North and South Americas, Australia), in North Africa, in the Middle East and in South Asia, where until a few years ago it was historically considered extremely rare. Therefore, celiac disease is spread worldwide as in a common "Global Village", and greater levels of awareness and attention on gluten intolerance are needed, both in the Old and in the New World.