Very heavy alcohol consumption and smoking are independent risks for CP. A minority of patients with pancreatitis currently seen at US referral centers report very heavy drinking.

Pancreatitis is a complex, progressively destructive inflammatory disorder. Alcohol was long thought to be the primary causative agent, but genetic contributions have been of interest since the discovery that rare PRSS1, CFTR, and SPINK1 variants were associated with pancreatitis risk. We now report two significant genome-wide associations identified and replicated at PRSS1-PRSS2 (1×10-12) and x-linked CLDN2 (p < 1×10-21) through a two-stage genome-wide study (Stage 1, 676 cases and 4507 controls; Stage 2, 910 cases and 4170 controls). The PRSS1 variant affects susceptibility by altering expression of the primary trypsinogen gene. The CLDN2 risk allele is associated with atypical localization of claudin-2 in pancreatic acinar cells. The homozygous (or hemizygous male) CLDN2 genotype confers the greatest risk, and its alleles interact with alcohol consumption to amplify risk. These results could partially explain the high frequency of alcohol-related pancreatitis in men – male hemizygous frequency is 0.26, female homozygote is 0.07.

Background: Recurrent acute pancreatitis (RAP) and chronic pancreatitis (CP) are complex syndromes associated with numerous etiologies, clinical variables and complications. We developed the North American Pancreatitis Study 2 (NAPS2) to be sufficiently powered to understand the complex environmental, metabolic and genetic mechanisms underlying RAP and CP. Methods: Between August 2000 and September 2006, a consortium of 20 expert academic and private sites prospectively ascertained 1,000 human subjects with RAP or CP, plus 695 controls (spouse, family, friend or unrelated). Standardized questionnaires were completed by both the physicians and study subjects and blood was drawn for genomic DNA and biomarker studies. All data were double-entered into a database and systematically reviewed to minimize errors and include missing data. Results: A total of 1,000 subjects (460 RAP, 540 CP) and 695 controls who completed consent forms and questionnaires and donated blood samples comprised the final dataset. Data were organized according to diagnosis, supporting documentation, etiological classification, clinical signs and symptoms (including pain patterns and duration, and quality of life), past medical history, family history, environmental exposures (including alcohol and tobacco use), medication use and therapeutic interventions. Upon achieving the target enrollment, data were organized and classified to facilitate future analysis. The approaches, rationale and datasets are described, along with final demographic results. Conclusion: The NAPS2 consortium has successfully completed a prospective ascertainment of 1,000 subjects with RAP and CP from the USA. These data will be useful in elucidating the environmental, metabolic and genetic conditions, and to investigate the complex interactions that underlie RAP and CP.

Background & Aims Alcohol has been implicated in the development of chronic pancreatitis (CP) in 60%–90% patients, although percentages in the United States are not known. We investigated the frequency of alcohol-related CP at tertiary U.S. referral centers. Methods We studied data from patients with CP (n=539) and controls (n=695) enrolled in the North American Pancreatitis Study-2 from 2000 to 2006 at 20 U.S. referral centers. CP was defined by definitive evidence in imaging or histologic analyses. Subjects and physicians each completed a detailed study questionnaire. Using physician-assigned diagnoses, patients were assigned to the following etiology groups: alcohol (with/without other diagnoses), non-alcohol (any etiology of CP from other than alcohol), or idiopathic (no etiology identified). Results The distribution of patients among etiology groups were: alcohol (44.5%), non-alcohol (26.9%), and idiopathic (28.6%). Physicians identified alcohol as the etiology more frequently in men (59.4% in men vs 28.1% in women), but non-alcohol (18% in men vs 36.7% in women) and idiopathic etiologies (22.6% in men vs 35.2% in women) more often in women (P<0.01 for all comparisons). Non-alcohol etiologies were equally divided among obstructive, genetic, and other causes. Compared with controls, patients with idiopathic CP were more likely to have ever smoked (58.6% vs 49.7%, P<0.05) or have a history of chronic renal disease or failure (5.2% vs 1.2%, P<0.01). In multivariate analyses, smoking (ever, current, and amount) was independently associated with idiopathic CP. Conclusions The frequency of alcohol-related CP at tertiary U.S. referral centers is lower than expected. Idiopathic CP and non-alcohol etiologies represent a large subgroup, particularly among women. Smoking is an independent risk factor for idiopathic CP.

Objective IBS is a common gut disorder of uncertain pathogenesis. Among other factors, genetics and certain foods are proposed to contribute. Congenital sucrase–isomaltase deficiency (CSID) is a rare genetic form of disaccharide malabsorption characterised by diarrhoea, abdominal pain and bloating, which are features common to IBS. We tested sucrase–isomaltase (SI) gene variants for their potential relevance in IBS. Design We sequenced SI exons in seven familial cases, and screened four CSID mutations (p.Val557Gly, p. Gly1073Asp, p.Arg1124Ter and p.Phe1745Cys) and a common SI coding polymorphism (p.Val15Phe) in a multicentre cohort of 1887 cases and controls. We studied the effect of the 15Val to 15Phe substitution on SI function in vitro. We analysed p.Val15Phe genotype in relation to IBS status, stool frequency and faecal microbiota composition in 250 individuals from the general population. Results CSID mutations were more common in patients than asymptomatic controls (p=0.074; OR=1.84) and Exome Aggregation Consortium reference sequenced individuals (p=0.020; OR=1.57). 15Phe was detected in 6/7 sequenced familial cases, and increased IBS risk in case–control and population-based cohorts, with best evidence for diarrhoea phenotypes (combined p=0.00012; OR=1.36). In the population-based sample, 15Phe allele dosage correlated with stool frequency (p=0.026) and Parabacteroides faecal microbiota abundance (p=0.0024). The SI protein with 15Phe exhibited 35% reduced enzymatic activity in vitro compared with 15Val (p<0.05). Conclusions SI gene variants coding for disaccharidases with defective or reduced enzymatic activity predispose to IBS. This may help the identification of individuals at risk, and contribute to personalising treatment options in a subset of patients.