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.

CFTR is a dynamically regulated anion channel. Intracellular WNK1-SPAK activation causes CFTR to change permeability and conductance characteristics from a chloride-preferring to bicarbonate-preferring channel through unknown mechanisms. Two severe CFTR mutations (CFTRsev) cause complete loss of CFTR function and result in cystic fibrosis (CF), a severe genetic disorder affecting sweat glands, nasal sinuses, lungs, pancreas, liver, intestines, and male reproductive system. We hypothesize that those CFTR mutations that disrupt the WNK1-SPAK activation mechanisms cause a selective, bicarbonate defect in channel function (CFTRBD) affecting organs that utilize CFTR for bicarbonate secretion (e.g. the pancreas, nasal sinus, vas deferens) but do not cause typical CF. To understand the structural and functional requirements of the CFTR bicarbonate-preferring channel, we (a) screened 984 well-phenotyped pancreatitis cases for candidate CFTRBD mutations from among 81 previously described CFTR variants; (b) conducted electrophysiology studies on clones of variants found in pancreatitis but not CF; (c) computationally constructed a new, complete structural model of CFTR for molecular dynamics simulation of wild-type and mutant variants; and (d) tested the newly defined CFTRBD variants for disease in non-pancreas organs utilizing CFTR for bicarbonate secretion. Nine variants (CFTR R74Q, R75Q, R117H, R170H, L967S, L997F, D1152H, S1235R, and D1270N) not associated with typical CF were associated with pancreatitis (OR 1.5, p = 0.002). Clones expressed in HEK 293T cells had normal chloride but not bicarbonate permeability and conductance with WNK1-SPAK activation. Molecular dynamics simulations suggest physical restriction of the CFTR channel and altered dynamic channel regulation. Comparing pancreatitis patients and controls, CFTRBD increased risk for rhinosinusitis (OR 2.3, p<0.005) and male infertility (OR 395, p<<0.0001). WNK1-SPAK pathway-activated increases in CFTR bicarbonate permeability are altered by CFTRBD variants through multiple mechanisms. CFTRBD variants are associated with clinically significant disorders of the pancreas, sinuses, and male reproductive system.

Background & Aims Idiopathic chronic pancreatitis (ICP) is a complex inflammatory disorder associated with multiple genetic and environmental factors. In individuals without cystic fibrosis (CF), variants of CFTR that inhibit bicarbonate conductance but maintain chloride conductance might selectively impair secretion of pancreatic juice, leading to trypsin activation and pancreatitis. We investigated whether sequence variants in the gene encoding the pancreatic secretory trypsin inhibitor, SPINK1, further increase the risk of pancreatitis in these patients. Methods We screened patients with ICP (sporadic or familial) and controls for variants in SPINK1 associated with chronic pancreatitis (CP) risk (in exon 3) and in all 27 exons of CFTR. The final study group included 53 patients with sporadic ICP, 27 probands with familial ICP, and 150 unrelated controls, plus 503 controls for limited genotyping. CFTR wild-type (wt) and p.R75Q were cloned and expressed in HEK293 cells and relative conductances of HCO3− and Cl− were measured. Results SPINK1 variants were identified in 36% of subjects and 3% controls (odds ratio [OR]=16.5). One variant of CFTR that has not been associated with CF, p.R75Q, was found in 16% of subjects and 5.4% controls (OR=3.4). Co-inheritance of CFTR p.R75Q and SPINK1 variants occurred in 8.75% of patients and 0.15% controls (OR=62.5). Patch-clamp recordings of cells that expressed CFTR p.R75Q demonstrated normal chloride currents but significantly reduced bicarbonate currents (P=0.0001). Conclusions The CFTR variant p.R75Q causes a selective defect in bicarbonate conductance and increases risk for pancreatitis. Co-inheritance of CF-associated, and some not associated, CFTR variants with SPINK1 variants significantly increase risk of ICP.

Purpose of review Chronic pancreatitis is a syndrome characterized by chronic inflammation of the pancreas, with variable pain, calcifications, necrosis, fatty replacement, fibrosis and scarring and other complications. Disease susceptibility, severity, progression and pain patterns vary widely and do not necessarily parallel one another. Much of the variability in susceptibility to recurrent acute and chronic pancreatitis is now clearly shown to be related to genetic differences between patients. This review highlights recent advances and future directions in genetic research. Recent findings The strongest risk factors are associated with genetic variations in PRSS1, SPINK1, CFTR, and to a lesser extent, CTRC and CASR. The latest research suggest that a single factor rarely causes pancreatitis, and the majority of patients with recurrent acute and chronic pancreatitis have multiple variants in a gene, or epistatic interactions between multiple genes, coupled with environmental stressors. Summary Pancreatic diseases have a strong genetic component. Rather than a classic Mendelian disorder, recurrent acute and chronic pancreatitis represents truly complex diseases with the interaction and synergism of multiple genetic and environmental factors. The future will require new predictive models to guide prevention and therapy.

OBJECTIVES:Recurrent acute pancreatitis (RAP) is a complex inflammatory disorder that may progress to fibrosis and other irreversible features recognized as chronic pancreatitis (CP). Chymotrypsinogen C (CTRC) protects the pancreas by degrading prematurely activated trypsinogen. Rare mutations are associated with CP in Europe and Asia. We evaluated the occurrence of CTRC variants in subjects with RAP, CP, and controls from the North American Pancreatitis Study II cohort.METHODS:CP (n=694), RAP (n=448), and controls (n=1017) of European ancestry were evaluated. Subgroup analysis included CFTR and SPINK1 variants, alcohol, and smoking.RESULTS:We identified previously reported rare pathogenic CTRC A73T, R254W, and K247_R254del variants, intronic variants, and G60G (c.180 C>T; rs497078). Compared with controls (minor allele frequency (MAF)=10.8%), c.180T was associated with CP (MAF=16.8%, P<0.00001) but not RAP (MAF=11.9% P=NS). Trend test indicated co-dominant risk for CP (CT odds ratio (OR)=1.36, 95% confidence interval (CI)=1.13–1.64, P=0.0014; TT OR=3.98, 95% CI=2.10–7.56, P<0.0001). The T allele was significantly more frequent with concurrent pathogenic CFTR variants and/or SPINK1 N34S (combined 22.9% vs. 16.1%, OR 1.92, 95% C.I. 1.26–2.94, P=0.0023) and with alcoholic vs. non-alcoholic CP etiologies (20.8% vs. 12.4%, OR=1.9, 95% CI=1.30–2.79, P=0.0009). Alcohol and smoking generally occurred together, but the frequency of CTRC c.180 T in CP, but not RAP, was higher among never drinkers–ever smokers (22.2%) than ever drinker–never smokers (10.8%), suggesting that smoking rather than alcohol may be the driving factor in this association.CONCLUSIONS:The common CTRC variant c.180T acts as disease modifier that promotes progression from RAP to CP, especially in patients with CFTR or SPINK1 variants, alcohol, or smoking.

Introduction: Diabetes mellitus (DM) is a complication of chronic pancreatitis (CP). Whether pancreatogenic diabetes associated with CP-DM represents a discrete pathophysiologic entity from type 2 DM (T2DM) remains uncertain. Addressing this question is needed for development of specific measures to manage CP-DM. We approached this question from a unique standpoint, hypothesizing that if CP-DM and T2DM are separate disorders, they should be genetically distinct. To test this hypothesis, we sought to determine whether a genetic risk score (GRS) based on validated single nucleotide polymorphisms for T2DM could distinguish between groups with CP-DM and T2DM. Methods: We used 60 T2DM single nucleotide polymorphisms to construct a weighted GRS in 1,613 subjects from the North American Pancreatitis Study 2 and 2,685 subjects from the Multi-Ethnic Study of Atherosclerosis, all of European origin. Results: The mean GRS was identical between 321 subjects with CP-DM and 423 subjects with T2DM (66.53 vs 66.42, P = 0.95), and the GRS of both diabetic groups was significantly higher than that of nondiabetic controls (n = 3,554, P < 0.0001). Exploratory analyses attempting to enrich the CP-DM group for pancreatogenic diabetes, such as eliminating diabetes diagnosed before CP, requiring pancreas-specific comorbidities, or removing those with a family history of diabetes, did not improve the ability of the GRS to distinguish between CP-DM and T2DM. Discussion: Recognizing that we lacked a gold standard to define CP-DM, our study suggests that CP-DM may be a subtype of T2DM, a notion that should be tested in future, large prospective studies.

Background/Objectives Acute pancreatitis (AP) is a complex inflammatory syndrome with unpredictable progression to systemic inflammation and multi-organ dysfunction syndrome (MODS). Tumor necrosis factor alpha (TNF–α) is a cytokine that may link inflammation to the systemic inflammatory response syndrome (SIRS), which usually precedes MODS. Small genetic cohort studies of the TNFA promoter in AP produced ambiguous results. We performed a comprehensive evaluation of TNFA promoter variants to assess both susceptibility to AP and risk of progression to MODS. Methods We prospectively ascertained 401 controls and 211 patients with AP that were assessed for persistent SIRS (>48 hours) and MODS. MODS was defined as failure of ≥2 organ systems (cardiovascular, pulmonary, and/or renal) persisting more than 48 hours. Subjects were genotyped by DNA sequencing and analyzed for SNPs at −1031 C/T (rs1799964), −863 A/C (rs1800630), −857 C/T (rs1799724), −308 A/G (rs1800629), and −238 A/G (rs361525). Results Twenty-three of 211 AP patients (11%) developed MODS. TNFA promoter variants were not associated with susceptibility to AP, but progression to MODS was associated with the minor allele at −1031C (56.5% vs. 32.4% P=0.022, OR: 2.7; 95%CI: 1.12–6.51) and −863A (43.5% vs. 21.8% P=0.022, OR: 2.76; 95%CI: 1.12–6.74). Conclusion TNFA promoter variants do not alter susceptibility to AP, but rather the TNF–α expression-enhancing −1031C and −863A alleles significantly increased the risk of AP progression to MODS. These data, within the context of previous studies, clarify the risk of specific genetic variants in TNFA and therefore the role of TNF–α in the overall AP syndrome.

Background & Aims: Idiopathic chronic pancreatitis (ICP) is the second most common subtype of CP. In 1994, researchers reported the bimodal age at onset of ICP symptoms: early-onset ICP (EO-ICP; median age, 19.2 years) and late-onset ICP (LO-ICP; median age, 56.2 years). Ages of onset and clinical features of ICP differed from those of alcohol-related CP (ACP). However, variants in PRSS1 had not yet been associated with ICP. We reexamined ages of onset of ICP in a large, North American cohort of patients, and investigated the effects of genetic factors and alcohol use in patients with EO-ICP, LO-ICP, or ACP. Methods: We performed a cross-sectional analysis of patients with CP of European ancestry enrolled in the North American Pancreatitis Study 2 studies, a prospective study of 1195 patients with CP from 26 centers in the United States from August 2000 through December 2014. We compared age at onset of symptoms for 130 patients with CP who were lifetime abstainers from alcohol (61 patients with early onset and 69 patients with late onset), 308 light to moderate alcohol drinkers with CP, and 225 patients with ACP and heavy to very heavy alcohol use. DNA from available patients was analyzed for variants associated with CP in SPINK1, CFTR, and CTRC. The Kruskal-Wallis test was used to compare continuous variables across groups and based on genetic variants. Results: Median ages at onset of symptoms were 20 years for patients with EO-ICP and no alcohol use, 58 years for patients with LO-ICP and no alcohol use, 47 years for light to moderate alcohol drinkers with CP, and 44 years for patients with ACP. A higher proportion of patients with EO-ICP had constant pain (65%) than patients with LO-ICP (31%) (P=.04). A higher proportion of patients with ACP had pseudocysts (43%) than patients with EO-ICP (11%)(P=.001). A higher proportion of patients with EO-ICP had pathogenic variants in SPINK1, CFTR, or CTRC (49%) than patients with LO-ICP (23%), light to moderate alcohol drinking with CP (26%), or ACP (23%) (P=.001). Among patients with variants in SPINK1, those with EO-ICP had onset of symptoms at a median age of 12 years, and light to moderate alcohol drinkers with CP had an age at onset of 24 years. Among patients with variants in CFTR, light to moderate alcohol drinkers had an age at onset of symptoms of 41 years, but this variant did not affect age at onset of EO-ICP or ACP. Conclusions:We confirmed previously reported ages at onset of symptoms for EO-ICP and LO-ICP in a North American cohort. We found differences in clinical features among patients with EO-ICP, LO-ICP, and ACP. Almost half of patients with EO-ICP have genetic variants associated with CP, compared to about one-quarter of patients with LO-CP or ACP. Genetic variants affect ages at onset of symptoms in some groups.