Integrated DNA Methylation/RNA Profiling in Middle Temporal Gyrus of Alzheimer's Disease.

Alzheimer's disease is a neurodegenerative disorder clinically defined by gradual cognitive impairment and alteration in executive function. We conducted an epigenome-wide association study (EWAS) of a clinically and neuropathologically characterized cohort of 296 brains, including Alzheimer's disease (AD) and non-demented controls (ND), exploring the relationship with the RNA expression from matched donors. We detected 5246 CpGs and 832 regions differentially methylated, finding overlap with previous EWAS but also new associations. CpGs previously identified in ANK1, MYOC, and RHBDF2 were differentially methylated, and one of our top hits (GPR56) was not previously detected. ANK1 was differentially methylated at the region level, along with APOE and RHBDF2. Only a small number of genes showed a correlation between DNA methylation and RNA expression statistically significant. Multiblock partial least-squares discriminant analysis showed several CpG sites and RNAs discriminating AD and ND (AUC = 0.908) and strongly correlated with each other. Furthermore, the CpG site cg25038311 was negatively correlated with the expression of 22 genes. Finally, with the functional epigenetic module analysis, we identified a protein-protein network characterized by inverse RNA/DNA methylation correlation and enriched for "Regulation of insulin-like growth factor transport", with IGF1 as the hub gene. Our results confirm and extend the previous EWAS, providing new information about a brain region not previously explored in AD DNA methylation studies. The relationship between DNA methylation and gene expression is not significant for most of the genes in our sample, consistently with the complexities in the gene expression regulation.

MiR130b from Schlafen4+ MDSCs stimulates epithelial proliferation and correlates with preneoplastic changes prior to gastric cancer.

The myeloid differentiation factor Schlafen4 (Slfn4) marks a subset of myeloid-derived suppressor cells (MDSCs) in the stomach during Helicobacter-induced spasmolytic polypeptide-expressing metaplasia (SPEM). OBJECTIVE: To identify the gene products expressed by Slfn4+-MDSCs and to determine how they promote SPEM. DESIGN: We performed transcriptome analyses for both coding genes (mRNA by RNA-Seq) and non-coding genes (microRNAs using NanoString nCounter) using flow-sorted SLFN4+ and SLFN4- cells from Helicobacter-infected mice exhibiting metaplasia at 6 months postinfection. Thioglycollate-elicited myeloid cells from the peritoneum were cultured and treated with IFNα to induce the T cell suppressor phenotype, expression of MIR130b and SLFN4. MIR130b expression in human gastric tissue including gastric cancer and patient sera was determined by qPCR and in situ hybridisation. Knockdown of MiR130b in vivo in Helicobacter-infected mice was performed using Invivofectamine. Organoids from primary gastric cancers were used to generate xenografts. ChIP assay and Western blots were performed to demonstrate NFκb p65 activation by MIR130b. RESULTS: MicroRNA analysis identified an increase in MiR130b in gastric SLFN4+ cells. Moreover, MIR130b colocalised with SLFN12L, a human homologue of SLFN4, in gastric cancers. MiR130b was required for the T-cell suppressor phenotype exhibited by the SLFN4+ cells and promoted Helicobacter-induced metaplasia. Treating gastric organoids with the MIR130b mimic induced epithelial cell proliferation and promoted xenograft tumour growth. CONCLUSION: Taken together, MiR130b plays an essential role in MDSC function and supports metaplastic transformation.

Common variants in NOD2 and IL23R are not associated with inflammatory bowel disease in Indians.

BACKGROUND AND AIM: Ulcerative colitis (UC) and Crohn's disease (CD) are two major phenotypes of inflammatory bowel disease (IBD) that present with inflammation of the colon or the entire gastrointestinal tract, respectively. Genome-wide association studies have confirmed the role of nucleotide-binding oligomerization domain protein-2 (NOD2) variants and identified several other genes associated with IBD. We investigated whether variants in NOD2 and interleukin-23 receptor (IL23R) are associated with IBD in a well-characterized case-control cohort from southern India. METHODS: We recruited 652 patients (411 UC and 241 CD) using established diagnostic criteria and 442 age-, sex-, and ethnically-matched, normal individuals. By direct sequencing, we screened the complete NOD2 gene and genotyped the R381Q variant in IL23R, and performed an association analysis and genotype-phenotype correlation analysis. RESULTS: The clinical presentation of UC and CD patients did not differ significantly from the Europeans. We observed a monomorphic status for three common disease-susceptible variants, R702W, G908R, and 1007fs in NOD2; three other single nucleotide polymorphisms, P268S, R459R, and R587R, had a comparable minor allele frequency in patients and controls. Compared to Europeans, we found a low frequency (∼1%) of the protective allele at R381Q in IL23R and no statistically-significant association with IBD (odds ratio = 0.87; 95% confidence interval = 0.26-2.86; P>0.05). CONCLUSIONS: Our study suggests that variants in the NOD2 gene and the protective variant R381Q in IL23R are not associated with IBD in Indians. Additional variants in these or other candidate genes might play a major role in the pathophysiology of IBD in Indians.

Oral buffered esomeprazole is superior to i.v. pantoprazole for rapid rise of intragastric pH: a wireless pH metry analysis.

BACKGROUND AND AIMS: A pH of more than 6 is required for clot stability and hemostasis. Intravenous proton pump inhibitors have a rapid onset of action compared to oral and have been preferred for management of non-variceal bleeding. Intravenous pantoprazole has been used extensively. Buffered esomeprazole (BE) is an oral preparation consisting of an inner core of non-enteric-coated esomeprazole with a shell of sodium bicarbonate. The buffer protects against acid degradation of esomeprazole in addition to immediate antacid action. The aim of this study was to assess the efficacy of BE for raising and maintaining an intragastric pH of more than 6 in comparison to i.v. pantoprazole in equivalent dosing. METHODS: A randomized two-way cross-over study was conducted. Ten healthy volunteers were randomized to twice daily BE 40 mg or pantoprazole 40 mg i.v. bolus. Intragastric pH was measured with a wireless pH radiotelemetry capsule (Bravo, Medtronic). A 2-week washout period was given between doses. RESULTS: BE achieved a steady pH of more than 6 in a median time of 2 min (range 1-5 min) after the first dose. The mean % time that intragastric pH was more than 6.0 for BE was 96%, and 90% of the 24-h period compared to pantoprazole (47% and 18%), P = 0.000. A median pH (interquartile range) for the BE group was 6.2 (6.175-6.2) which was higher than i.v. pantoprazole 4.60 (4.5-5.0) (P = 0.005). CONCLUSION: BE achieves and maintains a pH of more than 6 within minutes of administration. It was significantly superior to i.v. pantoprazole in equivalent dosing. This finding could have implications in the management of non-variceal bleed where a rapid and sustained pH of more than 6 is desirable.

Hepatic cholesterol transporter ABCG8 polymorphisms in gallstone disease in an Indian population.

BACKGROUND AND AIM: Gallstone formation is characterized by the abnormal regulation of cholesterol trafficking and solubilization. The prevalence of gallstone disease (GSD) differs between ethnic groups sharing the common environment. These differences can be explained by a genetic predisposition to gallstone formation. Studies have identified single nucleotide polymorphisms (SNP) D19H and T400K in the cholesterol transporter gene ATP-binding cassette, subfamily G, member 8 (ABCG8) in patients with cholesterol gallstones. The aim of this study was to analyze the relationship between D19H and T400K polymorphisms in the ABCG8 gene and GSD in an Indian population, and the effects of these polymorphisms on cholesterol levels in sera and bile. METHODS: A total of 226 patients with GSD were analyzed for their lipid profile in plasma and bile. A total of 289 controls were recruited, and their plasma lipid profile was analyzed by standard protocols. The genotype of SNP D19H and T400K of ABCG8 was analyzed in 226 patients and 222 control samples. SNP D19H was analyzed by direct sequencing, and SNP T400K genotyping was assayed by the amplification refractory mutation system-polymerase chain reaction. RESULTS: There was no significant difference in the allelic distribution of SNP T400K between the GSD and gallstone-free groups (P > 0.05), but the distribution of the SNP variant, D19H, was significantly higher (P = 0.017, odds ratio = 2.274) in patients compared to controls. The analysis of serum and bile cholesterol followed a strong association with genotypes. CONCLUSION: SNP D19H, but not SNP T400K, in the ABCG8 gene is significantly associated with GSD in an Indian population.

Malnutrition is not an etiological factor in the development of tropical pancreatitis--a case-control study of southern Indian patients.

BACKGROUND AND AIM: Malnutrition is implicated as an etiological factor in tropical pancreatitis (TP). The aim of the present study was to elucidate whether malnutrition is the cause or the result of TP. METHODS: Consecutive recently diagnosed patients with TP were evaluated for their nutritional status and dietary patterns before and after the onset of TP. The nutritional status of patients before the onset of TP was compared with that of healthy controls to demonstrate the role of malnutrition as an etiological factor for TP. RESULTS: Of 256 consecutive patients with chronic pancreatitis, 89 were diagnosed as TP patients with disease duration of less than 1 year (mean age 32.14 +/- 14 years; 60% males) and comprised the study group. The nutritional status before the onset of TP was comparable with that of controls (n = 101) with 15% of patients and 12% of the controls being malnourished (BMI < 18.5 kg/m2). However, after the onset of TP, 52% (n = 46) of patients lost weight and the percentage of malnourished patients increased from 15% to 38% (p = < 0.001) indicating that there was significant weight loss after the disease onset. When the causes of weight loss were evaluated, it was found that low calorie intake significantly contributed to weight loss (p = 0.001). CONCLUSION: Malnutrition is not an etiological factor of TP and weight loss occurred as a result of low calorie intake after the onset of TP.

Trypsinogen copy number mutations in patients with idiopathic chronic pancreatitis.

BACKGROUND & AIMS: We have recently reported that the triplication of a approximately 605 kilobase segment containing the PRSS1 (encoding cationic trypsinogen) and PRSS2 (encoding anionic trypsinogen) genes causes hereditary pancreatitis. Here we went further to investigate whether this copy number mutation could account for some unidentified French white patients with idiopathic chronic pancreatitis (ICP) or familial chronic pancreatitis (FCP) as well as Indian patients with tropical calcific pancreatitis (TCP). METHODS: Patients and controls were screened by means of previously described quantitative fluorescent multiplex polymerase chain reaction and/or genotyping of the microsatellite marker rs3222967. RESULTS: The approximately 605 kilobase triplication and a novel duplication (confirmed by fluorescence in situ hybridization) of the trypsinogen locus were detected in 10 and 2 of 202 ICP patients, respectively (age of disease onset, 20 years. However, the 2 trypsinogen copy number mutations were observed in neither 103 FCP patients nor 268 Indian TCP patients. CONCLUSIONS: Our findings revealed the molecular basis of 6% of the young ICP patients and further demonstrated that chronic pancreatitis is a genomic disorder. Our findings also add to the mounting evidence showing that trypsinogen gene mutations do not appear to play an important role in the pathogenesis of TCP in the Indian population. Finally, a dividend of this study is that we have provided convincing evidence to show that all 5 previously described copy number variations involving PRSS1 or/and PRSS2 are artifacts.

TCF7L2 gene polymorphisms do not predict susceptibility to diabetes in tropical calcific pancreatitis but may interact with SPINK1 and CTSB mutations in predicting diabetes.

BACKGROUND: Tropical calcific pancreatitis (TCP) is a type of chronic pancreatitis unique to developing countries in tropical regions and one of its important features is invariable progression to diabetes, a condition called fibro-calculous pancreatic diabetes (FCPD), but the nature of diabetes in TCP is controversial. We analysed the recently reported type 2 diabetes (T2D) associated polymorphisms in the TCF7L2 gene using a case-control approach, under the hypothesis that TCF7L2 variants should show similar association if diabetes in FCPD is similar to T2D. We also investigated the interaction between the TCF7L2 variants and N34S SPINK1 and L26V CTSB mutations, since they are strong predictors of risk for TCP. METHODS: Two polymorphisms rs7903146 and rs12255372 in the TCF7L2 gene were analyzed by direct sequencing in 478 well-characterized TCP patients and 661 healthy controls of Dravidian and Indo-European ethnicities. Their association with TCP with diabetes (FCPD) and without diabetes was tested in both populations independently using chi-square test. Finally, a meta analysis was performed on all the cases and controls for assessing the overall significance irrespective of ethnicity. We dichotomized the whole cohort based on the presence or absence of N34S SPINK1 and L26V CTSB mutations and further subdivided them into TCP and FCPD patients and compared the distribution of TCF7L2 variants between them. RESULTS: The allelic and genotypic frequencies for both TCF7L2 polymorphisms, did not differ significantly between TCP patients and controls belonging to either of the ethnic groups or taken together. No statistically significant association of the SNPs was observed with TCP or FCPD or between carriers and non-carriers of N34S SPINK1 and L26V CTSB mutations. The minor allele frequency for rs7903146 was different between TCP and FCPD patients carrying the N34S SPINK1 variant but did not reach statistical significance (OR = 1.59, 95% CI = 0.93-2.70, P = 0.09), while, TCF7L2variant showed a statistically significant association between TCP and FCPD patients carrying the 26V allele (OR = 1.69, 95% CI = 1.11-2.56, P = 0.013). CONCLUSION: Type 2 diabetes associated TCF7L2 variants are not associated with diabetes in TCP. Since, TCF7L2 is a major susceptibility gene for T2D, it may be hypothesized that the diabetes in TCP patients may not be similar to T2D. Our data also suggests that co-existence of TCF7L2 variants and the SPINK1 and CTSB mutations, that predict susceptibility to exocrine damage, may interact to determine the onset of diabetes in TCP patients.

Comprehensive screening for reg1alpha gene rules out association with tropical calcific pancreatitis.

AIM: To investigate the allelic and haplotypic association of reg1alpha gene with tropical calcific pancreatitis (TCP). Since TCP is known to have a variable genetic basis, we investigated the interaction between mutations in the susceptibility genes, SPINK1 and CTSB with reg1alpha polymorphisms. METHODS: We analyzed the polymorphisms in the reg1alpha gene by sequencing the gene including its promoter region in 195 TCP patients and 150 ethnically matched controls, compared their allele and haplotype frequencies, and their association with the pathogenesis and pancreaticolithiasis in TCP and fibro-calculous pancreatic diabetes. RESULTS: We found 8 reported and 2 novel polymo-rphisms including an insertion-deletion polymorphism in the promoter region of reg1alpha. None of the 5'UTR variants altered any known transcription factor binding sites, neither did any show a statistically significant association with TCP. No association with any reg1alpha variants was observed on dichotomization of patients based on their N34S SPINK1 or L26V CTSB status. CONCLUSION: Polymorphisms in reg1alpha gene, including the regulatory variants singly or in combination with the known mutations in SPINK1 and/or CTSB genes, are not associated with tropical calcific pancreatitis.

Lack of significant association of an insertion/deletion polymorphism in the angiotensin converting enzyme (ACE) gene with tropical calcific pancreatitis.

BACKGROUND: The genetic basis of tropical calcific pancreatitis (TCP) is different and is explained by mutations in the pancreatic secretory trypsin inhibitor (SPINK1) gene. However, mutated SPINK1 does not account for the disease in all the patients, neither does it explain the phenotypic heterogeneity between TCP and fibro-calculous pancreatic diabetes (FCPD). Recent studies suggest a crucial role for pancreatic renin-angiotensin system during chronic hypoxia in acute pancreatitis and for angiotensin converting enzyme (ACE) inhibitors in reducing pancreatic fibrosis in experimental models. We investigated the association of ACE gene insertion/deletion (I/D) polymorphism in TCP patients using a case-control approach. Since SPINK1 mutations are proposed a modifier role, we also investigated its interaction with the ACE gene variant. METHODS: We analyzed the I/D polymorphism in the ACE gene (g.11417_11704del287) in 171 subjects comprising 91 TCP and 80 FCPD patients and compared the allelic and genotypic frequency in them with 99 healthy ethnically matched control subjects. RESULTS: We found 46% and 21% of TCP patients, 56% and 19.6% of FCPD patients and 54.5% and 19.2% of the healthy controls carrying the I/D and D/D genotypes respectively (P>0.05). No significant difference in the clinical picture was observed between patients with and without the del allele at the ACE in/del polymorphism in both categories. No association was observed with the presence or absence of N34S SPINK1 mutation in these patients. CONCLUSION: We conclude that the ACE insertion/deletion variant does not show any significant association with the pathogenesis, fibrosis and progression of tropical calcific pancreatitis and the fibro-calculous pancreatic diabetes.

DNA defects, epigenetics, and gene expression in cancer-adjacent breast: a study from The Cancer Genome Atlas.

Recurrence rates after breast-conserving therapy may depend on genomic characteristics of cancer-adjacent, benign-appearing tissue. Studies have not evaluated recurrence in association with multiple genomic characteristics of cancer-adjacent breast tissue. To estimate the prevalence of DNA defects and RNA expression subtypes in cancer-adjacent, benign-appearing breast tissue at least 2 cm from the tumor margin, cancer-adjacent, pathologically well-characterized, benign-appearing breast tissue specimens from The Cancer Genome Atlas project were analyzed for DNA sequence, copy-number variation, DNA methylation, messenger RNA (mRNA) sequence, and mRNA/microRNA expression. Additional samples were also analyzed by at least one of these genomic data types and associations between genomic characteristics of normal tissue and overall survival were assessed. Approximately 40% of cancer-adjacent, benign-appearing tissues harbored genomic defects in DNA copy number, sequence, methylation, or in RNA sequence, although these defects did not significantly predict 10-year overall survival. Two mRNA/microRNA expression phenotypes were observed, including an active mRNA subtype that was identified in 40% of samples. Controlling for tumor characteristics and the presence of genomic defects, this active subtype was associated with significantly worse 10-year survival among estrogen receptor (ER)-positive cases. This multi-platform analysis of breast cancer-adjacent samples produced genomic findings consistent with current surgical margin guidelines, and provides evidence that extratumoral RNA expression patterns in cancer-adjacent tissue predict overall survival among patients with ER-positive disease.

Assessment of Circulating MicroRNAs for the Diagnosis and Disease Activity Evaluation in Patients with Ulcerative Colitis by Using the Nanostring Technology.

BACKGROUND: Clinical decision and patient care management in inflammatory bowel diseases is largely based on the assessment of clinical symptoms, while the biomarkers currently in use poorly reflect the actual disease activity. Therefore, the identification of novel biomarkers will serve an unmet clinical need for IBD screening and patient management. We examined the utility of circulating microRNAs for diagnosis and disease activity monitoring in patients with ulcerative colitis (UC). METHODS: Blood serum microRNAs were isolated from patients with UC with active and inactive disease and healthy donors. High-throughput microRNA profiling was performed using the Nanostring technology platform. Clinical disease activity was captured by calculating the partial Mayo score. C-reactive protein was measured in patients with UC as part of their clinical monitoring. The profiles of circulating microRNAs and C-reactive protein were correlated with clinical disease indices. RESULTS: We have identified a signature of 12 circulating microRNAs that differentiate patients with UC from control subjects. Moreover, 6 of these microRNAs significantly correlated with UC disease activity. Importantly, a set of 4 microRNAs (hsa-miR-4454, hsa-miR-223-3p, hsa-miR-23a-3p, and hsa-miR-320e), which correlated with UC disease activity were found to have higher sensitivity and specificity values than C-reactive protein. CONCLUSIONS: Circulating microRNAs provide a novel diagnostic and prognostic marker for patients with UC. The use of an FDA-approved platform could accelerate the application of microRNA screening in a gastrointenstinal clinical setting. When used in combination with current diagnostic and disease activity assessment modalities, microRNAs could improve both IBD screening and care management.

Subcutaneous adipose tissue macrophage infiltration is associated with hepatic and visceral fat deposition, hyperinsulinemia, and stimulation of NF-κB stress pathway.

OBJECTIVE: To examine in obese young adults the influence of ethnicity and subcutaneous adipose tissue (SAT) inflammation on hepatic fat fraction (HFF), visceral adipose tissue (VAT) deposition, insulin sensitivity (SI), ß-cell function, and SAT gene expression. RESEARCH DESIGN AND METHODS: SAT biopsies were obtained from 36 obese young adults (20 Hispanics, 16 African Americans) to measure crown-like structures (CLS), reflecting SAT inflammation. SAT, VAT, and HFF were measured by magnetic resonance imaging, and SI and ß-cell function (disposition index [DI]) were measured by intravenous glucose tolerance test. SAT gene expression was assessed using Illumina microarrays. RESULTS: Participants with CLS in SAT (n = 16) were similar to those without CLS in terms of ethnicity, sex, and total body fat. Individuals with CLS had greater VAT (3.7 ± 1.3 vs. 2.6 ± 1.6 L; P = 0.04), HFF (9.9 ± 7.3 vs. 5.8 ± 4.4%; P = 0.03), tumor necrosis factor-α (20.8 ± 4.8 vs. 16.2 ± 5.8 pg/mL; P = 0.01), fasting insulin (20.9 ± 10.6 vs. 9.7 ± 6.6 mU/mL; P < 0.001) and glucose (94.4 ± 9.3 vs. 86.8 ± 5.3 mg/dL; P = 0.005), and lower DI (1,559 ± 984 vs. 2,024 ± 829 × 10(-4) min(-1); P = 0.03). Individuals with CLS in SAT exhibited upregulation of matrix metalloproteinase-9 and monocyte antigen CD14 genes, as well as several other genes belonging to the nuclear factor-κB (NF-κB) stress pathway. CONCLUSIONS: Adipose tissue inflammation was equally distributed between sexes and ethnicities. It was associated with partitioning of fat toward VAT and the liver and altered ß-cell function, independent of total adiposity. Several genes belonging to the NF-κB stress pathway were upregulated, suggesting stimulation of proinflammatory mediators.

Cortisol is negatively associated with insulin sensitivity in overweight Latino youth.

CONTEXT AND OBJECTIVE: The purpose of the present study was to investigate the cross-sectional and longitudinal associations of serum morning cortisol and aspects of insulin action in Latino children and adolescents (8-13 yr) at risk for type 2 diabetes. DESIGN AND PARTICIPANTS: The present study includes a cross-sectional analysis in 211 participants and a longitudinal analysis in a subset of 143 participants. RESULTS: At baseline, cortisol was negatively associated with fasting glucose (r = 0.23; P < 0.01), ß-cell function (disposition index, r = -0.24; P < 0.05), and acute insulin response to glucose (r = -0.27; P < 0.05). Baseline cortisol was also significantly related to the change in insulin sensitivity over 1 yr (r = -0.23; P < 0.05). These results did not differ by Tanner stage or sex. CONCLUSIONS: Cortisol contributes to the reduction in insulin sensitivity at an early age in Latino children and adolescents. Specifically, cortisol is negatively associated with potential compensatory mechanisms for insulin resistance, such as increased ß-cell function and increased insulin release to a glucose challenge, by exacerbating the progression toward insulin resistance in this population. The results underline the relevance of glucocorticoid reduction for the prevention of metabolic disease in Latino children and adolescents.

Effects of PNPLA3 on liver fat and metabolic profile in Hispanic children and adolescents.

OBJECTIVE: A genome-wide study of adults identified a variant of PNPLA3 (rs738409) associated with ∼twofold higher liver fat. The purpose of this study was to examine the influence of PNPLA3 genotype on liver fat and other related metabolic outcomes in obese Hispanic children and adolescents. RESEARCH DESIGN AND METHODS: Three hundred and twenty-seven Hispanics aged 8-18 years were genotyped for rs738409. One hundred and eighty-eight subjects had measures of visceral (VAT) and subcutaneous (SAT) adipose tissue volume and hepatic (HFF) and pancreatic (PFF) fat fraction by magnetic resonance imaging. One hundred and thirty-nine subjects did not have HFF measures but had extensive measures of insulin sensitivity and fasting lipids. RESULTS: Liver fat in GG subjects was 1.7 and 2.4 times higher than GC and CC (11.1 ± 0.8% in GG vs. 6.6 ± 0.7% in GC and 4.7 ± 0.9% in CC; P < 0.0001), and this effect was observed even in the youngest children (8-10 years of age). The variant was not associated with VAT, SAT, PFF, or insulin sensitivity or other glucose/insulin indexes. However, Hispanic children carrying the GG genotype had significantly lower HDL cholesterol (40.9 ± 10.9 in CC vs. 37.0 ± 8.3 in CG vs. 35.7 ± 7.4 in GG; P = 0.03) and a tendency toward lower free fatty acid levels (P = 0.06). CONCLUSIONS: These results provide new evidence that the effect of the PNPLA3 variant is apparent in Hispanic children and adolescents, is unique to fat deposition in liver as compared with other ectopic depots examined, and is associated with lower HDL cholesterol.

Genetic mechanisms underlying the pathogenesis of tropical calcific pancreatitis.

Chronic pancreatitis is known to be a heterogeneous disease with varied etiologies. Tropical calcific pancreatitis (TCP) is a severe form of chronic pancreatitis unique to developing countries. With growing evidence of genetic factors contributing to the pathogenesis of TCP, this review is aimed at compiling the available information in this field. We also propose a two hit model to explain the sequence of events in the pathogenesis of TCP.