The hereditary pancreatitis gene maps to long arm of chromosome 7

2. Classification and Diagnosis of Diabetes: Standards of Care in Diabetes-2023

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

WITHDRAWN: Clinical interpretation of PRSS1 gene variants in patients with pancreatitis

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Clinics and Research in Hepatology and Gastroenterology, Volume 45, Issue 1, 2021, 101497. https://doi.org/10.1016/j.clinre.2020.07.004. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal

Expanding ACMG variant classification guidelines into a general framework

BACKGROUND

The American College of Medical Genetics and Genomics (ACMG)-recommended five variant classification categories (pathogenic, likely pathogenic, uncertain significance, likely benign, and benign) have been widely used in medical genetics. However, these guidelines are fundamentally constrained in practice owing to their focus upon Mendelian disease genes and their dichotomous classification of variants as being either causal or not. Herein, we attempt to expand the ACMG guidelines into a general variant classification framework that takes into account not only the continuum of clinical phenotypes, but also the continuum of the variants' genetic effects, and the different pathological roles of the implicated genes.

MAIN BODY

As a disease model, we employed chronic pancreatitis (CP), which manifests clinically as a spectrum from monogenic to multifactorial. Bearing in mind that any general conceptual proposal should be based upon sound data, we focused our analysis on the four most extensively studied CP genes, PRSS1, CFTR, SPINK1 and CTRC. Based upon several cross-gene and cross-variant comparisons, we first assigned the different genes to two distinct categories in terms of disease causation: CP-causing (PRSS1 and SPINK1) and CP-predisposing (CFTR and CTRC). We then employed two new classificatory categories, "predisposing" and "likely predisposing", to replace ACMG's "pathogenic" and "likely pathogenic" categories in the context of CP-predisposing genes, thereby classifying all pathologically relevant variants in these genes as "predisposing". In the case of CP-causing genes, the two new classificatory categories served to extend the five ACMG categories whilst two thresholds (allele frequency and functional) were introduced to discriminate "pathogenic" from "predisposing" variants.

CONCLUSION

Employing CP as a disease model, we expand ACMG guidelines into a five-category classification system (predisposing, likely predisposing, uncertain significance, likely benign, and benign) and a seven-category classification system (pathogenic, likely pathogenic, predisposing, likely predisposing, uncertain significance, likely benign, and benign) in the context of disease-predisposing and disease-causing genes, respectively. Taken together, the two systems constitute a general variant classification framework that, in principle, should span the entire spectrum of variants in any disease-related gene. The maximal compliance of our five-category and seven-category classification systems with the ACMG guidelines ought to facilitate their practical application.

Hereditary Pancreatitis-25 Years of an Evolving Paradigm: Frank Brooks Memorial Lecture 2021

ABSTRACT

The identification of the genetic basis of hereditary pancreatitis in 1996 confirmed the critical role of trypsinogen in this disease and opened a new avenue of research on pancreatitis-associated genetic risk factors and their mechanism of action. Through the following 25 years, the ensuing discoveries fundamentally changed our understanding of pancreatitis pathogenesis, clarified the role of trypsinogen autoactivation in disease onset and progression, and set the stage for future therapeutic interventions. This Frank Brooks Memorial Lecture was delivered on November 4, 2021, at the 52nd Annual Meeting of the American Pancreatic Association, held in Miami Beach, Florida.

Trypsinogen (PRSS1 and PRSS2) gene dosage correlates with pancreatitis risk across genetic and transgenic studies: a systematic review and re-analysis

Trypsinogen (PRSS1, PRSS2) copy number gains and regulatory variants have both been proposed to elevate pancreatitis risk through a gene dosage effect (i.e., by increasing the expression of wild-type protein). However, to date, their impact on pancreatitis risk has not been thoroughly evaluated whilst the underlying pathogenic mechanisms remain to be explicitly investigated in mouse models. Genetic studies of the rare trypsinogen duplication and triplication copy number variants (CNVs), and the common rs10273639C variant, were collated from PubMed and/or ClinVar. Mouse studies that analyzed the influence of a transgenically expressed wild-type human PRSS1 or PRSS2 gene on the development of pancreatitis were identified from PubMed. The genetic effects of the different risk genotypes, in terms of odds ratios, were calculated wherever appropriate. The genetic effects of the rare trypsinogen duplication and triplication CNVs were also evaluated by reference to their associated disease subtypes. We demonstrate a positive correlation between increased trypsinogen gene dosage and pancreatitis risk in the context of the rare duplication and triplication CNVs, and between the level of trypsinogen expression and disease risk in the context of the heterozygous and homozygous rs10273639C-tagged genotypes. We retrospectively identify three mouse transgenic studies that are informative in relation to the pathogenic mechanism underlying the trypsinogen gene dosage effect in pancreatitis. Trypsinogen gene dosage correlates with pancreatitis risk across genetic and transgenic studies, highlighting the fundamental role of dysregulated expression of wild-type trypsinogen in the etiology of pancreatitis. Specifically downregulating trypsinogen expression in the pancreas may serve as a potential therapeutic and/or prevention strategy for pancreatitis.

2. Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes-2022

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

The reversion variant (p.Arg90Leu) at the evolutionarily adaptive p.Arg90 site in CELA3B predisposes to chronic pancreatitis

A gain-of-function missense variant in the CELA3B gene, p.Arg90Cys (c.268C>T), has recently been reported to cause pancreatitis in an extended pedigree. Herein, we sequenced the CELA3B gene in 644 genetically unexplained French chronic pancreatitis (CP) patients (all unrelated) and 566 controls. No obvious loss-of-function variants were identified. None of the six low-frequency or common missense variants detected showed significant association with CP. Nor did the aggregate rare/very rare missense variants (n = 14) show any significant association with CP. However, p.Arg90Leu (c.269G>T), which was found in four patients but no controls, and affects the same amino acid as p.Arg90Cys, serves to revert p.Arg90 to the human elastase ancestral allele. As p.Arg90Leu has previously been shown to exert a similar functional effect to that of p.Arg90Cys, our findings not only confirm the involvement of CELA3B in the etiology of CP but also pinpoint a new evolutionarily adaptive site in the human genome.

Clinical interpretation of PRSS1 variants in patients with pancreatitis

Since the description of the PRSS1 gene encoding the cationic trypsinogen as being involved in dominant hereditary pancreatitis, more than 50 PRSS1 variants have been reported. Among the PRSS1 variants that have been classified as pathogenic, some have a high penetrance and others have a low penetrance. Assessing the clinical relevance of PRSS1 variants is often complicated in the absence of functional evidence and interpretation of rare variants is not very easy in clinical practice. The aim of this study was to review the different variants identified in the PRSS1 gene and to classify them according to their degree of deleterious effect. This classification was based on the results of several in vitro experiments and on population data, in comparing the allelic frequency of each variant in patients with pancreatitis and in unaffected individuals. This review should help geneticists and clinicians in charge of patient's care and genetic counseling to interpret molecular results.

2. Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes-2021

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc21-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc21-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Clinical interpretation of SPINK1 and CTRC variants in pancreatitis

Since the description of the SPINK1 gene encoding the serine protease inhibitor Kazal type 1 and the CTRC gene encoding the Chymotrypsin C as being involved in chronic pancreatitis, more than 56 SPINK1 and 87 CTRC variants have been reported. Assessing the clinical relevance of SPINK1 and CTRC variants is often complicated in the absence of functional evidence and interpretation of rare variants is not very easy in clinical practice. The aim of this study was to review the different variants identified in these two genes and to classify them according to their degree of damaging effect. This classification was based on the results of in vitro experiments, in silico analysis using different prediction tools, and on population data, in comparing the allelic frequency of each variant in patients with pancreatitis and in unaffected control individuals. This review should help geneticists and clinicians in charge of patient's care and genetic counseling to interpret the results of genetic studies.

Trypsin activity governs increased susceptibility to pancreatitis in mice expressing human PRSS1R122H

Currently, an effective targeted therapy for pancreatitis is lacking. Hereditary pancreatitis (HP) is a heritable, autosomal-dominant disorder with recurrent acute pancreatitis (AP) progressing to chronic pancreatitis (CP) and a markedly increased risk of pancreatic cancer. In 1996, mutations in PRSS1 were linked to the development of HP. Here, we developed a mouse model by inserting a full-length human PRSS1R122H gene, the most commonly mutated gene in human HP, into mice. Expression of PRSS1R122H protein in the pancreas markedly increased stress signaling pathways and exacerbated AP. After the attack of AP, all PRSS1R122H mice had disease progression to CP, with similar histologic features as those observed in human HP. By comparing PRSS1R122H mice with PRSS1WT mice, as well as enzymatically inactivated Dead-PRSS1R122H mice, we unraveled that increased trypsin activity is the mechanism for R122H mutation to sensitize mice to the development of pancreatitis. We further discovered that trypsin inhibition, in combination with anticoagulation therapy, synergistically prevented progression to CP in PRSS1R122H mice. These animal models help us better understand the complex nature of this disease and provide powerful tools for developing and testing novel therapeutics for human pancreatitis.

2. Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes-2020

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee (https://doi.org/10.2337/dc20-SPPC), a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc20-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Two Mutations Induce Early-Onset Severe Chronic Pancreatitis

The SPINK1 protein is a potent antiprotease that can inactivate any intrapancreatic trypsin activity that would otherwise induce autodigestion of the pancreas. SPINK1 mutations have been recognized to be associated with chronic pancreatitis in patients without a family history of pancreatitis. We here describe the case of a 24-year-old woman referred to our service for recurrent abdominal pain and search for the cause of chronic calcifying pancreatitis, who was found to carry 2 SPINK1 mutations.

PRSS1, SPINK1, CFTR, and CTRC Pathogenic Variants in Korean Patients With Idiopathic Pancreatitis

BACKGROUND

This study aimed to identify pathogenic variants of PRSS1, SPINK1, CFTR, and CTRC genes in Korean patients with idiopathic pancreatitis.

METHODS

The study population consisted of 116 Korean subjects (65 males, 51 females; mean age, 30.4 yr, range, 1-88 yr) diagnosed with idiopathic chronic pancreatitis (ICP), idiopathic recurrent acute pancreatitis (IRAP), or idiopathic acute pancreatitis (IAP). We analyzed sequences of targeted regions in the PRSS1, SPINK1, CFTR, and CTRC genes, copy numbers of PRSS1 and SPINK1, and clinical data from medical records.

RESULTS

We identified three types of pathogenic PRSS1 variants in 11 patients, including p.N29I (n=1), p.R122H (n=1), and p.G208A (n=9). Sixteen patients exhibited heterozygous pathogenic variants of SPINK1, including c.194+2T>C (n=12), p.N34S (n=3), and a novel pathogenic splicing variation c.194+1G>A. A heterozygous CFTR p.Q1352H pathogenic variant was detected in eight patients. One patient carried a heterozygous CTRC p.P249L pathogenic variant, which is a known high-risk variant for pancreatitis. All patients had normal PRSS1 and SPINK1 gene copy numbers. Weight loss occurred more frequently in patients carrying the p.G208A pathogenic variant, while pancreatic duct stones occurred more frequently in patients with the c.194+2T>C pathogenic variant.

CONCLUSIONS

Pathogenic variants of PRSS1, SPINK1, and CFTR were associated with idiopathic pancreatitis, while pathogenic variants of CTRC were not. Copy number variations of PRSS1 and SPINK1 were not detected.

Hereditary pancreatitis: current perspectives

Hereditary pancreatitis (HP) is a rare cause of acute, recurrent acute, and chronic pancreatitis. It may present similarly to other causes of acute and chronic pancreatitis, and often there has been a protracted evaluation prior to the diagnosis of HP. Since it was first described in 1952, multiple genetic defects that affect the action of digestive enzymes in the pancreas have been implicated. The most common mutations involve the PRSS1, CFTR, SPINK1, and CTRC genes. New mutations in these genes and previously unrecognized mutations in other genes are being discovered due to the increasing use of next-generation genomic sequencing. While the inheritance pathways of these genetic mutations may be variable and complex, sometimes involving coinheritance of other mutations, the clinical presentation of patients tends to be similar. Interactions with environmental triggers often play a role. Patients tend to present at an early age (prior to the second decade of life) and have a significantly increased risk for the development of pancreatic adenocarcinoma. Patients with HP may develop sequelae of chronic pancreatitis such as strictures and fluid collections as well as exocrine and endocrine insufficiency. Management of patients with HP involves avoidance of environmental triggers, surveillance for pancreatic adenocarcinoma, medical therapy for endocrine and exocrine insufficiency, pain management, and endoscopic or surgical treatment for complications. Care for affected patients should be individualized, with an emphasis on early diagnosis and multidisciplinary involvement to develop a comprehensive treatment strategy.

Genetic and phenotypic heterogeneity in tropical calcific pancreatitis

Tropical calcific pancreatitis (TCP) is a form of chronic non-alcoholic pancreatitis initially reported in the developing parts of the tropical world. The clinical phenotype of TCP has undergone marked changes since its first description in 1968. The disease is now seen in relatively older people with less severe symptoms. In addition, there are varying reports on the proportion of cases presenting with imaging abnormalities like calcification, ductal dilation, and glandular atrophy. Significant progress has also been made in understanding the etiopathology of TCP. The role of malnutrition and cassava toxicity in its pathogenesis is disproven and few studies have focused on the role of micronutrient deficiency and oxidative stress in the etiopathogenesis of TCP. Emerging evidence support an important role for genetic risk factors in TCP. Several studies have shown that, rather than mutations in trypsinogens, variants in serine protease inhibitor kazal type 1, cathepsin B, chymotrypsin C, cystic fibrosis transmembrane regulator, and carboxypeptidase A1, predict risk of TCP. These studies also provided evidence of mutational heterogeneity between TCP and chronic pancreatitis in Western populations. The current review summarizes recent advances that have implications in the understanding of the pathophysiology and thus, heterogeneity in genotype-phenotype correlations in TCP.

Genetics of acute and chronic pancreatitis: An update

Progress made in identifying the genetic susceptibility underlying acute and chronic pancreatitis has benefitted the clinicians in understanding the pathogenesis of the disease in a better way. The identification of mutations in cationic trypsinogen gene (PRSS1 gene; functional gain mutations) and serine protease inhibitor kazal type 1 (SPINK1 gene; functional loss mutations) and other potential susceptibility factors in genes that play an important role in the pancreatic secretory functions or response to inflammation during pancreatic injury has changed the current concepts and understanding of a complex multifactorial disease like pancreatitis. An individual’s susceptibility to the disease is governed by genetic factors in combination with environmental factors. Candidate gene and genetic linkage studies have identified polymorphisms in cationic trypsinogen (PRSS1), SPINK1, cystic fibrosis trans-membrane conductance regulator (CFTR), Chymotrypsinogen C (CTRC), Cathepsin B (CTSB) and calcium sensing receptor (CASR). Individuals with polymorphisms in the mentioned genes and other as yet identified genes are at an enhanced risk for the disease. Recently, polymorphisms in genes other than those involved in “intra-pancreatic trypsin regulatory mechanism” namely Claudin-2 (CLDN2) and Carboxypeptidase A1 (CPA1) gene have also been identified for their association with pancreatitis. With ever growing number of studies trying to identify the genetic susceptibility in the form of single nucleotide polymorphisms, this review is an attempt to compile the available information on the topic.

Hereditary pancreatitis: dilemmas in differential diagnosis and therapeutic approach

INTRODUCTION

Hereditary pancreatitis (HP) is a rare, heterogeneous familial disease and should be suspected in any patient who has suffered at least two attacks of acute pancreatitis for which there is no underlying cause and unexplained chronic pancreatitis with a family history in a first- or second-degree relative. Genetic factors have been implied in cases of familial chronic pancreatitis. The most common PRSS1 mutations worldwide are the R122H and N29I variants.

CLINICAL FEATURES

HP usually appears with an acute, a recurrent acute, and a chronic phase, referring to the inflammation of the pancreas and the symptoms' onset and duration. The clinical features of acute pancreatitis begin in childhood and last less than 6 months. HP carries a 50-70-fold increased risk of pancreatic cancer within 7-30 years of disease onset. HP diagnosis is defined by the presence of a detected cationic trypsinogen gene mutation (with or without clinical or radiological manifestations of chronic pancreatitis) or when the patient's family satisfies the requirements of the EUROPAC.

TREATMENT

With regard to the therapeutic approach, pancreatic enzyme replacement therapy and analgesics are offered to control pain. In addition, endoscopic and surgical intersections are reserved for all relevant complications. Unfortunately, surgical removal of affected pancreatic tissue does not necessarily guarantee the patient's long-term survival. Furthermore, the prognostic factors and the efficacy of extended resection remain controversial.

PRSS1 and SPINK1 mutations in idiopathic chronic and recurrent acute pancreatitis

AIM: To identify gene mutations in PRSS1 and SPINK1 in individuals with early onset idiopathic chronic or recurrent acute pancreatitis.

METHODS: The cationic trypsinogen gene (PRSS1; exons 2 and 3) and the serine protease inhibitor Kazal 1 gene (SPINK1; exon 3) were selectively amplified and sequenced from blood samples of 19 patients admitted to the Pancreas Clinic at our institution with chronic pancreatitis and/or idiopathic recurrent acute pancreatitis that were diagnosed or with onset before age 35. Fifty healthy volunteers served as controls. Whole blood samples were collected and gene specific sequences were amplified by polymerase chain reaction (PCR). All PCR products were subsequently sequenced in order to identify the presence of any mutations.

RESULTS: Nineteen patients with pancreatitis (14 males; median age 24 years, range 15-48 years) were included in this study, of which five showed the presence of gene mutations. Direct sequencing results indicated the presence of two previously unidentified mutations in exon 2 of PRSS1 (V39E and N42S) in two patients with recurrent acute pancreatitis. Two cases had the N34S SPINK1 mutation. Analysis of the relatives of one patient homozygous for this mutation showed that five of the six family members carried the N34S SPINK1 mutation. Of these members, three were healthy heterozygous carriers and two were homozygotes (one sibling had diabetes, the other was healthy). Another patient was heterozygous for a novel SPINK1 mutation located on exon 3 (V46D). All members from this patient’s family had normal genotypes, indicating that it was a de novo mutation. No mutations in either gene were present in the control subjects.

CONCLUSION: Two novel PRSS1 mutations and one novel SPINK1 mutation were identified in Mexican patients with early onset idiopathic recurrent acute pancreatitis.

Human cationic trypsinogen (PRSS1) variants and chronic pancreatitis

Variations in the serine protease 1 (PRSS1) gene encoding human cationic trypsinogen have been conclusively associated with autosomal dominant hereditary pancreatitis and sporadic nonalcoholic chronic pancreatitis. Most high-penetrance PRSS1 variants increase intrapancreatic trypsin activity by stimulating trypsinogen autoactivation and/or by inhibiting chymotrypsin C-dependent trypsinogen degradation. Alternatively, some PRSS1 variants can cause trypsinogen misfolding, which results in intracellular retention and degradation with consequent endoplasmic reticulum stress. However, not all PRSS1 variants are pathogenic, and clinical relevance of rare variants is often difficult to ascertain. Here we review the PRSS1 variants published since 1996 and discuss their functional properties and role in chronic pancreatitis.

Long-term outcomes of total pancreatectomy and islet auto transplantation for hereditary/genetic pancreatitis

BACKGROUND

Chronic pancreatitis is a debilitating disease resulting from many causes. The subset with hereditary/genetic pancreatitis (HGP) not only has chronic pain, but also an increased risk for pancreatic cancer. Long-term outcomes of total pancreatectomy (TP) and islet autogeneic transplantation (IAT) for chronic pancreatitis due to HGP are not clear.

STUDY DESIGN

We reviewed a prospectively maintained database of 484 TP-IATs from 1977 to 2012 at a single center. The outcomes (eg, pain relief, narcotic use, β-cell function, health-related quality of life measures) of patients who received TP-IAT for HGP (protease trypsin 1, n = 38; serine protease inhibitor Kazal type 1, n = 9; cystic fibrosis transmembrane conductance regulator, n = 14; and familial, n = 19) were evaluated and compared with those with non-hereditary/nongenetic causes.

RESULTS

All 80 patients with HGP were narcotic dependent and failed endoscopic management or direct pancreatic surgery. Post TP-IAT, 90% of the patients were pancreatitis pain free with sustained pain relief; >65% had partial or full β-cell function. Compared with nonhereditary causes, HGP patients were younger (22 years old vs 38 years old; p ≤ 0.001), had pancreatitis pain of longer duration (11.6 ± 1.1 years vs 9.0 ± 0.4 years; p = 0.016), had a higher pancreas fibrosis score (7 ± 0.2 vs 4.8 ± 0.1; p ≤ 0.001), and trended toward lower islet yield (3,435 ± 361 islet cell equivalent vs 3,850 ± 128 islet cell equivalent; p = 0.28). Using multivariate logistic regression, patients with non-HGP causes (p = 0.019); lower severity of pancreas fibrosis (p < 0.001); shorter duration of years with pancreatitis (p = 0.008); and higher transplant islet cell equivalent per kilogram body weight (p ≤ 0.001) were more likely to achieve insulin independence (p < 0.001). There was a significant improvement in health-related quality of life from baseline by RAND 36-Item Short Form Health Survey and in physical and mental component health-related quality of life scores (p < 0.001). None of the patients in the entire cohort had cancer of pancreatic origin in the liver or elsewhere develop during 2,936 person-years of follow-up.

CONCLUSIONS

Total pancreatectomy and IAT in patients with chronic pancreatitis due to HGP cause provide long-term pain relief (90%) and preservation of β-cell function. Patients with chronic painful pancreatitis due to HGP with a high lifetime risk of pancreatic cancer should be considered earlier for TP-IAT before pancreatic inflammation results in a higher degree of pancreatic fibrosis and islet cell function loss.

Long-term outcomes of total pancreatectomy and islet auto transplantation for hereditary/genetic pancreatitis

BACKGROUND

Chronic pancreatitis is a debilitating disease resulting from many causes. The subset with hereditary/genetic pancreatitis (HGP) not only has chronic pain, but also an increased risk for pancreatic cancer. Long-term outcomes of total pancreatectomy (TP) and islet autogeneic transplantation (IAT) for chronic pancreatitis due to HGP are not clear.

STUDY DESIGN

We reviewed a prospectively maintained database of 484 TP-IATs from 1977 to 2012 at a single center. The outcomes (eg, pain relief, narcotic use, β-cell function, health-related quality of life measures) of patients who received TP-IAT for HGP (protease trypsin 1, n = 38; serine protease inhibitor Kazal type 1, n = 9; cystic fibrosis transmembrane conductance regulator, n = 14; and familial, n = 19) were evaluated and compared with those with non-hereditary/nongenetic causes.

RESULTS

All 80 patients with HGP were narcotic dependent and failed endoscopic management or direct pancreatic surgery. Post TP-IAT, 90% of the patients were pancreatitis pain free with sustained pain relief; >65% had partial or full β-cell function. Compared with nonhereditary causes, HGP patients were younger (22 years old vs 38 years old; p ≤ 0.001), had pancreatitis pain of longer duration (11.6 ± 1.1 years vs 9.0 ± 0.4 years; p = 0.016), had a higher pancreas fibrosis score (7 ± 0.2 vs 4.8 ± 0.1; p ≤ 0.001), and trended toward lower islet yield (3,435 ± 361 islet cell equivalent vs 3,850 ± 128 islet cell equivalent; p = 0.28). Using multivariate logistic regression, patients with non-HGP causes (p = 0.019); lower severity of pancreas fibrosis (p < 0.001); shorter duration of years with pancreatitis (p = 0.008); and higher transplant islet cell equivalent per kilogram body weight (p ≤ 0.001) were more likely to achieve insulin independence (p < 0.001). There was a significant improvement in health-related quality of life from baseline by RAND 36-Item Short Form Health Survey and in physical and mental component health-related quality of life scores (p < 0.001). None of the patients in the entire cohort had cancer of pancreatic origin in the liver or elsewhere develop during 2,936 person-years of follow-up.

CONCLUSIONS

Total pancreatectomy and IAT in patients with chronic pancreatitis due to HGP cause provide long-term pain relief (90%) and preservation of β-cell function. Patients with chronic painful pancreatitis due to HGP with a high lifetime risk of pancreatic cancer should be considered earlier for TP-IAT before pancreatic inflammation results in a higher degree of pancreatic fibrosis and islet cell function loss.

Recent progress in pancreatic cancer

Pancreatic cancer is currently one of the deadliest of the solid malignancies. However, surgery to resect neoplasms of the pancreas is safer and less invasive than ever, novel drug combinations have been shown to improve survival, advances in radiation therapy have resulted in less toxicity, and enormous strides have been made in the understanding of the fundamental genetics of pancreatic cancer. These advances provide hope but they also increase the complexity of caring for patients. It is clear that multidisciplinary care that provides comprehensive and coordinated evaluation and treatment is the most effective way to manage patients with pancreatic cancer.

Recent progress in pancreatic cancer

Pancreatic cancer is currently one of the deadliest of the solid malignancies. However, surgery to resect neoplasms of the pancreas is safer and less invasive than ever, novel drug combinations have been shown to improve survival, advances in radiation therapy have resulted in less toxicity, and enormous strides have been made in the understanding of the fundamental genetics of pancreatic cancer. These advances provide hope but they also increase the complexity of caring for patients. It is clear that multidisciplinary care that provides comprehensive and coordinated evaluation and treatment is the most effective way to manage patients with pancreatic cancer.

Hereditary pancreatitis: endoscopic and surgical management

INTRODUCTION

Hereditary pancreatitis is a rare cause of chronic pancreatitis. In recent years, genetic mutations have been characterized. The rarity of this disorder has resulted in a gap in clinical knowledge. The aims were to characterize patients with hereditary pancreatitis and establish clinical guidelines.

METHODS

Pediatric and adult endoscopic, surgical, radiologic, and genetic databases from 1998 to 2012 were searched. Patients with recurrent acute or chronic pancreatitis and genetic mutation for either PRSS-1, SPINK-1, or CFTR or those who met the family history criteria were included. Patients with pancreatitis due to other causes, without a positive family history, familial pancreatic cancer, or cystic fibrosis, were excluded.

RESULTS

Eighty-seven patients were identified. Genetic testing confirmed the diagnosis in 54 patients (62 %). Eighty-five patients (98 %) underwent 263 endoscopic procedures including sphincterotomy (72 %), stone removal (49 %), and pancreatic duct stenting (82 %). Twenty-eight patients (32 %) have undergone 37 operations which included 19 resections and 18 drainage procedures. The interval between procedures for recurrent pain was longer for surgery than for endoscopic therapy (9.1 vs. 3.4 years, p < 0.05).

CONCLUSIONS

Most children and young adults with hereditary pancreatitis can be managed initially with endoscopic therapy. When surgery is undertaken, the procedure should be tailored to the pancreatic anatomy and cancer risk.

Hereditary pancreatitis for the endoscopist

Hereditary pancreatitis shares a majority of clinical and morphologic features with chronic alcoholic pancreatitis, but may present at an earlier age. The term hereditary pancreatitis has primarily been associated with mutations in the serine protease 1 gene (PRSS1) which encodes for cationic trypsinogen. PRSS1 mutations account for approximately 68-81% of hereditary pancreatitis. Mutations in other genes, primarily serine protease inhibitor Kazal type 1 (SPINK1) and the cystic fibrosis transmembrane conductance regulator (CFTR) are also associated with hereditary pancreatitis. While chronic alcoholic pancreatitis may develop in the fourth or fifth decades, patients with hereditary pancreatitis may develop symptoms in the first or second decades of life. Hereditary pancreatitis is diagnosed either by detecting a causative gene mutation or by the presence of chronic pancreatitis in two first-degree or three second-degree relatives, in two or more generations, without precipitating factors and with a negative workup for known causes. Patients with hereditary pancreatitis may have recurrent acute pancreatitis and may develop pancreatic exocrine and endocrine insufficiency. Hereditary pancreatitis may involve premature trypsinogen activation or decreased control of trypsin. Recurrent inflammation can lead to acute pancreatitis and subsequently to chronic pancreatitis with parenchymal calcification. There is a markedly increased risk of pancreatic carcinoma compared with the general population. Patients are often referred for evaluation of pancreatitis, biliary or pancreatic ductal dilatation, jaundice, biliary obstruction, pancreatic duct stone or stricture, pancreatic pseudocysts, and for evaluation for malignancy. Medical treatment includes pancreatic enzyme supplementation, nutritional supplementation, diabetes management, and palliation of pain. Patients should avoid tobacco use and alcohol exposure. Hereditary pancreatitis is reviewed and recommendations for genetic testing are discussed.

Genetic susceptibility to pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer death in both men and women in the United States. However, it has the poorest prognosis of any major tumor type, with a 5-yr survival rate of approximately 5%. Cigarette smoking, increased body mass index, heavy alcohol consumption, and a diagnosis of diabetes mellitus have all been demonstrated to increase risk of pancreatic cancer. A family history of pancreatic cancer has also been associated with increased risk suggesting inherited genetic factors also play an important role, with approximately 5-10% of pancreatic cancer patients reporting family history of pancreatic cancer. While the genetic basis for the majority of the familial clustering of pancreatic cancer remains unclear, several important pancreatic cancer genes have been identified. These consist of high penetrance genes including BRCA2 or PALB2, to more common genetic variation associated with a modest increase risk of pancreatic cancer such as genetic variation at the ABO blood group locus. Recent advances in genotyping and genetic sequencing have accelerated the rate at which novel pancreatic cancer susceptibility genes have been identified with several genes identified within the past few years. This review addresses our current understanding of the familial aggregation of pancreatic cancer, established pancreatic cancer susceptablity genes and how this knowledge informs risk assessment and screening for high-risk families.

An overview of hereditary pancreatitis

Hereditary pancreatitis is a rare cause of chronic pancreatitis. The prevalence was evaluated to 0.3/100000 in Western Countries. Genetic disorders are due to mutations of the PRSS1 gene on the long arm of the chromosome 7, encoding for the cationic trypsinogen. The inheritance pattern is autosomal dominant with an incomplete penetrance (80%). Since 1996, more than 30 mutations were found. The three more common mutations are R122H, N29I and A16V. First symptoms begin since childhood, mainly before 10 years old. Main symptoms are pancreatic pain and acute pancreatitis (>70%). CP morphological changes as pancreatic calcifications are diagnosed at a median age of 22-25 years. Exocrine and endocrine pancreatic insufficiency occurred in 34% and 26% at a median age of 29 and 38 years. No clinical differences exist according to the mutation type. No excess of mortality in hereditary pancreatitis population compared to general population was found, despite a real risk of cancer. The cumulative risks of pancreatic cancer at 50, 60 and, 75 years are 10%, 18.7% and, 53.5%, respectively. The relative risk of cancer increases in smokers and is evaluated to 8.55. Hereditary pancreatitis diagnosis permits to propose an adapted management in expert centres.

Chymotrypsin C mutations in chronic pancreatitis

Chronic pancreatitis is a persistent inflammatory disorder characterized by destruction of the pancreatic parenchyma, maldigestion, and chronic pain. Mutations in the chymotrypsin C (CTRC) gene encoding the digestive enzyme CTRC have been shown to increase the risk of chronic pancreatitis in European and Asian populations. Here, we review the biochemical properties and physiological functions of human CTRC, summarize the functional defects associated with CTRC mutations, and discuss mechanistic models that might explain the increased disease risk in carriers.

High incidence of PRSS1 and SPINK1 mutations in Korean children with acute recurrent and chronic pancreatitis

OBJECTIVES

We evaluated the frequencies and clinical consequences of mutations in the genes encoding cationic trypsinogen, serine protease 1 (PRSS1), and serine protease inhibitor Kazal type 1 (SPINK1) in children with acute recurrent pancreatitis (ARP) and chronic pancreatitis (CP).

PATIENTS AND METHODS

The study population consisted of 32 children with ARP or CP and 28 healthy controls. We analyzed clinical data and the sequences of the entire coding region and the intron-exon boundaries of the PRSS1 and SPINK1 genes from each patient.

RESULTS

Fifteen (46.9%) of the 32 patients had at least 1 PRSS1 or SPINK1 mutation. Four (12.5%) of the 32 patients carried the p.N29I, p.R122H, or p.N29T mutation or a p.G208A variant of the PRSS1 gene in a heterozygote state. Eleven (34.4%) of the 32 patients carried either the IVS3 + 2T>C or p.N34S mutation of the SPINK1 gene. No PRSS1 or SPINK1 mutations were identified in the control group. In particular, mutations were identified in 4 of our patients who experienced pancreas divisum with CP, whereas the remaining 2 patients with pancreas divisum and ARP did not have mutation.

CONCLUSIONS

The frequencies of the PRSS1 and SPINK1 mutations are relatively high in Korean children with ARP or CP. Mutations in the PRSS1 and SPINK1 genes are highly associated with the development of childhood ARP or CP. Our findings suggest that patients with genetic mutations combined with pancreas divisum tend to develop CP early.

Genetic basis of chronic pancreatitis in Asia Pacific region

Chronic pancreatitis (CP) is a disease characterized by irreversible destruction and fibrosis of the parenchyma, leading to pancreatic exocrine insufficiency. In developed countries, the etiology for 60% to 70% of CP amongst male patients is alcohol and 25% are classified as idiopathic chronic pancreatitis (ICP). The genetic predisposition to CP could be an inappropriate activation of trypsinogen in the pancreas. Two common haplotypes, c.101A>G (p.N34S) and c.-215G>A, and four intronic alterations of the serine protease inhibitor Kazal type 1 (SPINK1) gene have been found to increase the risk for CP in the Asia Pacific region. Hence, SPINK1 is thought to be a candidate gene for pancreatitis. A loss-of-function alteration in chymotrypsinogen C (CTRC) gene has been shown to be associated with tropical calcific pancreatitis (TCP). Cathepsin B (CTSB) is also found to be associated with TCP. However mutations in cationic and anionic trypsinogen gene do not play an important role in causing CP in Asia Pacific region.

Hereditary pancreatitis

Hereditary chronic pancreatitis (HCP) is a rare disease in which chronic pancreatitis develops in childhood. HCP has autosomal dominant inheritance with approximately 80% penetrance. Diagnostic criteria are not universally agreed upon but the EUROPAC trial defined it as two first-degree relatives or at least 3 second-degree relatives in two or more generations, with chronic pancreatitis for which there is no other etiology. The gene for HCP was originally identified on chromosome 7 and subsequently many other genes have been reported to be associated with HCP. To date, no single genetic alteration has been found that is necessary for the development of HCP. In a recent study, 81% of patients with HCP were found to have a mutation of the PRSS1 gene. Patients with HCP are at risk for developing exocrine and endocrine insufficiency and there is a 50-fold increased risk of pancreatic cancer in HCP patients as compared with the general population.

Genetic factors in chronic pancreatitis; implications for diagnosis, management and prognosis

Chronic pancreatitis (CP) is a clinical situation with persisting inflammation leading to destruction of the pancreas ensuing endocrine and exocrine failure. There are 4 subtypes: hereditary, idiopathic, alcoholic and tropical pancreatitis. Genetic factors can explain a significant proportion of CP cases. The PRSS1 gene, encoding cationic trypsinogen, was found to be correlated with hereditary CP. This signalled the extensive search for other candidate genes within the trypsin pathway. Genes like SPINK1 and CTRC are associated with CP and should be considered as important contributing factors rather than causative. The search for candidate genes not part of the trypsin pathway has been less successful and the only gene consistently associated with CP is the Cystic Fibrosis Transmembrane Regulator. In this review we will discuss the various CP subtypes in relation to the respective genetic variants. This review will also address the implications of genetic testing in daily clinical practise.

CFTR gene mutation in patients with apparently idiopathic pancreatitis: lack of phenotype-genotype correlation

BACKGROUND AND AIMS

Despite an extensive search, no cause is found for recurrent acute/chronic pancreatitis (idiopathic pancreatitis (IP)) in about 20% of patients. In these patients, CFTR gene mutations may be identified. The aims of this study were (1) to describe the natural history of pancreatitis associated with the CFTR mutation, (2) to look for genotype-phenotype correlations, and (3) to examine the frequency of CFTR mutations in a population of patients with IP.

RESULTS

100 consecutive patients with IP were included between 1998 and 2005. 50% had one of the 33 most frequent CFTR gene mutations (common CF mutations, uncommon mutations causing variable phenotypes and variants of unknown significance in 28, 44 and 28%, respectively). Patients with a CFTR gene mutation were significantly younger than those without (34 vs. 40 years, p = 0.03). Duration of follow-up (3.5 vs. 3 years), proportion of patients with acute pancreatitis as first symptom (76 vs. 74%) were not significantly different. Signs of chronic pancreatitis (ductal changes and pancreatic calcifications), pseudocysts, common bile duct stenosis, exocrine or endocrine insufficiency occurred in 36, 26, 4, 10 and 12% of patients with CFTR gene mutations respectively, which was not different from patients without mutations. No phenotype-genotype correlation was observed.

CONCLUSIONS

In patients with IP, clinical and radiological manifestations are not related to the presence of a CFTR gene mutation or to the type of mutation.

Pathology analysis reveals that dysplastic pancreatic ductal lesions are frequent in patients with hereditary pancreatitis

BACKGROUND & AIMS

Hereditary pancreatitis (HP) is a risk factor for pancreatic adenocarcinoma. We performed a retrospective, multicenter study to characterize and evaluate the frequency of pancreatic intraepithelial neoplasia (PanIN) and to describe the characteristics of fibrosis in pancreatic surgical specimens from patients with HP.

METHODS

Samples from partial pancreatectomies (n = 13) of patients with HP complications (n = 12; 7 males; mean age, 24 y; 1 patient underwent 2 surgeries over 16 years) were analyzed by histologic and immunohistologic analyses; patients with suspected or proven pancreatic adenocarcinoma were excluded. HP diagnosis was confirmed by analysis of PRSS1 mutations. Dysplastic lesions were described according to the PanIN classification.

RESULTS

Eleven patients were found to have the R122H mutation in PRSS1 and 1 patient was found to have the N29I mutation in PRSS1. Fifty-one PanIN lesions were observed in 10 specimens (77%): PanIN lesions 1a, 1b, 2, and 3 were observed in 8, 5, 8, and 5 specimens, respectively. The median number of PanIN lesions was 3.5 for each specimen. The density of the lesions was 2.6 per 10 cm(2). The size of lesions was greater than 0.5 mm in 55% of the samples. Two patients with PanIN-3 developed pancreatic cancer, 18 months and 44 years after surgery.

CONCLUSIONS

PanIN lesions are frequent, severe, and occur early in the course of HP. Among patients with PanINs, 50% had PanIN-3 lesions. Pancreatectomy could be considered as a prophylactic against pancreatic cancer in patients with high-grade dysplasia.

Outcomes of interventional ERCP in hereditary pancreatitis

GOALS

To clinically evaluate the patients with hereditary pancreatitis (HP) before the first, after the first and last interventional endoscopic retrograde cholangiopancreatography (ERCP), and at follow-up.

BACKGROUND

There are limited data evaluating the outcomes and role of interventional ERCP in HP.

STUDY

Between 1990 and 2008, 21 consecutive patients with HP were retrospectively assessed for response to therapeutic ERCP. Medical records were reviewed and a telephone survey was conducted to obtain information.

RESULTS

Patients underwent a total of 87 interventional ERCPs (mean 4, range: 1 to 11) and were followed-up for a mean period of 5 years (2 to 212 mo) from the last ERCP. The mean age at diagnosis, first ERCP, and follow-up was 15, 19, and 27 years (2 to 39 y), respectively. Eleven of 12 patients (92%) who received surgical therapy required subsequent interventional ERCPs. Before and after first ERCP mean pain scores decreased from 8.3 to 3.2 (P=0.001) and after last ERCP scores decreased to 2.7 (P=0.001). Yearly hospital visits including urgent care and emergency room visits decreased from 5.7 to 1.9 (P<0.001) and then to 1.6 (P=0.001). Daily oxycodone equivalent usage decreased from 39 to 34 mg (P=0.7) and then to 9.4 mg (P=0.05). Complications included pancreatitis in 3% with no perforations, bleeding, or infection.

CONCLUSIONS

Despite decompressive or resective surgeries in 12 of 21 patients, the majority (92%) developed subsequent complications and required endoscopic therapy. Endoscopic management for amenable lesions often requires multiple ERCPs. Interventional ERCPs in patients with HP is associated with decreased pain, analgesic usage, hospitalizations, and episodes of recurrent pancreatitis.

Alcoholic pancreatitis: pathogenesis, incidence and treatment with special reference to the associated pain

Alcoholic pancreatitis continues to stir up controversy. One of the most debated points is whether from onset it is a chronic disease or whether it progresses to a chronic form after repeated episodes of acute pancreatitis. Histological studies on patients with alcoholic pancreatitis have shown that the disease is chronic from onset and that alcoholic acute pancreatitis occurs in a pancreas already damaged by chronic lesions. Genetic factors may also play a role in the pathogenesis of alcoholic disease. The incidence of chronic alcoholic pancreatitis seems to have decreased in the last twenty years. Finally, recent therapeutic studies which have shown medical or surgical approaches capable of reducing the pain episodes in chronic pancreatitis patients will be described.

Hereditary pancreatitis in children: surgical implications with special regard to genetic background

PURPOSE

Hereditary pancreatitis (HP) is the primary etiology of chronic pancreatitis during childhood, progressing through recurrent episodes of acute pancreatitis and finally leading to pancreatic insufficiencies. Hereditary pancreatitis is because of mutations of the cationic trypsinogen (PRSS1) gene. Some other genes, such as SPINK1 or CFTR, have been associated with familial idiopathic chronic pancreatitis. The aim of our study was to clearly define diagnostic and therapeutic strategies for HP patients, through an analysis of our study group and a review of the literature.

METHODS

All children admitted from 1995 to 2007 with a final diagnosis of hereditary pancreatitis were restrospectively included in the study. We analyzed all medical records with special attention given to cases involving genetic screening (PRSS1, SPINK1, and CFTR genes).

RESULTS

Ten children were included. Eight had HP with PRSS1 mutation, 2 of them without a familial history of chronic pancreatitis. The 2 others patients had SPINK1 mutations. Three HP patients were operated on for acute complications of pancreatitis and are well with a mean follow-up of 5.5 years. No patient had pancreatic insufficiencies or weight loss.

CONCLUSIONS

Hereditary pancreatitis is associated with severe pancreatitis, with a greater risk of developing pancreatic cancer. It must therefore be diagnosed correctly and treated to prevent its considerable complications.

Mortality rate and risk factors in patients with hereditary pancreatitis: uni- and multidimensional analyses

OBJECTIVES

Patients with hereditary pancreatitis (HP) bear a high risk of pancreatic adenocarcinoma, but their life expectancy remains unknown. The objective of the study was to assess whether the high risk of cancer decreases survival.

METHODS

Inclusion criteria were the presence of a PRSS1 mutation with pancreatic symptoms or chronic pancreatitis in at least two first-degree relatives or three second-degree relatives without another cause. Survival rates were assessed according to risk factors. Excess mortality compared with the general French population was calculated (statistical Esteve model) for two periods (20-50 and 50-70 years), according to several risk factors.

RESULTS

The cohort comprised 189 patients. PRSS1 mutations were found in 66%. A total of 19 patients died at the median age of 60. In all, 10 deaths were attributable to HP, including 8 to pancreatic adenocarcinoma. Median overall survival for the whole cohort was 74 years (95% confidence interval (CI): 71-79). The presence of R122H mutation, gender, tobacco consumption in patients older than 18 years, and diabetes mellitus were not associated with differences in survival. Only patients with pancreatic cancer had decreased survival (P=0.008). Excess mortality risk compared with the general population was 0.02% between 20 and 50 years, and 0.61% between 50 and 70 years (NS). Gender, R122H mutation, diabetes, and tobacco use were not associated with excess mortality in these two periods.

CONCLUSIONS

Despite their high risk of cancer, HP patients do not have excess mortality risk compared with the general population, irrespective of gender, tobacco use, or diabetes mellitus. These data should be brought to the patient's attention.

[From the chronic pancreatitis to chronic pancreatites]

Chronic alcohol intake accounts for 60-90% of the cases of chronic pancreatitis, but other etiologies have been recognized and described in the very recent years. Genetic causes include mutations of the cationic trypsinogen gene PRSS1 (100 families in France), of its inhibitor SPINK1 and of the CFTR gene involved in cystic fibrosis. Auto-immune pancreatitis is often part of an "IgG4-related systemic disease" involving the biliary tract, the salivary glands, the retroperitoneum and/or the kidneys. Diagnostic criteria are now well-defined (HISORt of the Mayo Clinic), with ductal and parenchymal lesions on imaging that may mimick pancreatic adenocarcinoma. Corticoids are efficacious but recurrences are frequent and long-term outcome is still poorly known.

Familial pancreatic cancer

CONTEXT

Approximately 5% to 10% of individuals with pancreatic cancer report a history of pancreatic cancer in a close family member. In addition, several known genetic syndromes, such as familial breast cancer (BRCA2), the Peutz-Jeghers syndrome, and the familial atypical multiple mole melanoma syndrome, have been shown to be associated with an increased risk of pancreatic cancer. The known genes associated with these conditions can explain only a portion of the clustering of pancreatic cancer in families, and research to identify additional susceptibility genes is ongoing.

OBJECTIVE

To provide an understanding of familial pancreatic cancer and the pathology of familial exocrine pancreatic cancers.

DATA SOURCES

Published literature on familial aggregation of pancreatic cancer and familial exocrine pancreatic tumors.

CONCLUSIONS

Even in the absence of predictive genetic testing, the collection of a careful, detailed family history is an important step in the management of all patients with pancreatic cancer. While most pancreatic cancers that arise in patients with a family history are ductal adenocarcinomas, certain subtypes of pancreatic cancer have been associated with familial syndromes. Therefore, the histologic appearance of the pancreatic cancer itself, and/or the presence and appearance of precancerous changes in the pancreas, may increase the clinical index of suspicion for a genetic syndrome.

Familial pancreatic cancer

CONTEXT

Approximately 5% to 10% of individuals with pancreatic cancer report a history of pancreatic cancer in a close family member. In addition, several known genetic syndromes, such as familial breast cancer (BRCA2), the Peutz-Jeghers syndrome, and the familial atypical multiple mole melanoma syndrome, have been shown to be associated with an increased risk of pancreatic cancer. The known genes associated with these conditions can explain only a portion of the clustering of pancreatic cancer in families, and research to identify additional susceptibility genes is ongoing.

OBJECTIVE

To provide an understanding of familial pancreatic cancer and the pathology of familial exocrine pancreatic cancers.

DATA SOURCES

Published literature on familial aggregation of pancreatic cancer and familial exocrine pancreatic tumors.

CONCLUSIONS

Even in the absence of predictive genetic testing, the collection of a careful, detailed family history is an important step in the management of all patients with pancreatic cancer. While most pancreatic cancers that arise in patients with a family history are ductal adenocarcinomas, certain subtypes of pancreatic cancer have been associated with familial syndromes. Therefore, the histologic appearance of the pancreatic cancer itself, and/or the presence and appearance of precancerous changes in the pancreas, may increase the clinical index of suspicion for a genetic syndrome.

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.

Chronic pancreatitis: genetics and pathogenesis

Chronic pancreatitis (CP) is a persistent inflammation of the pancreas. Over the past 12 years, genetic studies of hereditary, familial, and idiopathic forms of CP have made great progress in defining the disease pathogenesis. Identification of gain-of-function missense and copy number mutations in the cationic trypsinogen gene (PRSS1) and loss-of-function variants in both the pancreatic secretory trypsin inhibitor (SPINK1) and chymotrypsinogen C (CTRC) genes has firmly established the pivotal role of prematurely activated trypsin within the pancreas in the etiology of CP. Loss-of-function variants in the cystic fibrosis transmembrane conductance regulator (CFTR) and calcium-sensing receptor (CASR) genes also increase the risk of CP. Here, we review recent developments in this rapidly evolving field, highlight the importance of gene-gene and gene-environment interactions in causing the disease, and discuss the opportunities and challenges in identifying novel genetic factors that affect susceptibility/resistance to CP.

Hereditary pancreatitis caused by a double gain-of-function trypsinogen mutation

Hereditary pancreatitis, an autosomal dominant disease with approximately 80% penetrance, can be caused by both 'gain-of-function' missense and copy number mutations in the cationic trypsinogen gene (PRSS1). Here we demonstrate a heterozygous hybrid PRSS2 (encoding anionic trypsinogen)/PRSS1 gene in a French white family with hereditary pancreatitis, by means of quantitative fluorescent multiplex PCR and RT-PCR analyses. The hybrid gene, in which exons 1 and 2 are derived from PRSS2 and exons 3-5 from PRSS1, apparently resulted from a non-allelic homologous recombination (NAHR) event between the chromosome 7 homologs or sister chromatids during meiosis. Interestingly, this hybrid gene causes the disease through a combination of its inherent 'double gain-of-function' effect, acting simultaneously as a 'quantitative' copy number mutation and a 'qualitative' missense mutation (i.e. the known disease-causing p.N29I mutation). Our finding reveals a previously unknown mechanism causing human inherited disease, enriches the lexicon of human genetic variation and goes beyond the known interaction between copy number variations (CNVs) and single nucleotide substitutions in health and disease. Our finding should also stimulate more interest in analyzing both types of genetic variation whenever one tries to determine the contribution of a specific locus to a given disease phenotype.

Concomitant autoimmune and genetic pancreatitis leads to severe inflammatory conditions

Chronic pancreatitis characterized by an early onset should be extensively investigated including the search for a mutation of the PRSS1, SPINK-1 or CFTR genes and potential features of autoimmune pancreatitis. We here describe a case of chronic pancreatitis with an onset at a very young age in which a mutation of the PRSS1 and several features of autoimmune pancreatitis were identified.

The inflammatory cascade in acute pancreatitis: relevance to clinical disease

Acute pancreatitis is an inflammatory condition that is initiated by the intra pancreatic activation of proteases. Pancreatic enzyme activation triggers a local and systemic inflammatory response that is associated with recruitment of inflammatory cells into the pancreas and a widespread up-regulation of inflammatory markers in distant tissues.

Hereditary chronic pancreatitis

Hereditary chronic pancreatitis (HCP) is a very rare form of early-onset chronic pancreatitis. Apart from young age at diagnosis and a slower progression, the clinical course, morphological features and laboratory findings of HCP do not differ from those of patients with alcoholic chronic pancreatitis. Diagnostic criteria and treatment of HCP also resemble those of chronic pancreatitis of other causes. The clinical presentation is highly variable and includes chronic abdominal pain, impairment of endocrine and exocrine pancreatic function, nausea and vomiting, maldigestion, diabetes, pseudocysts, bile-duct and duodenal obstruction, and rarely pancreatic cancer. Fortunately, the disease is mild in most patients. Mutations in the PRSS1 gene, encoding cationic trypsinogen, play a causative role in chronic pancreatitis. It has been shown that the PRSS1 mutations increase autocatalytic conversion of trypsinogen to active trypsin, and thus probably cause premature, intrapancreatic trypsinogen activation, disturbing the intrapancreatic balance of proteases and their inhibitors. Other genes--such as the anionic trypsinogen (PRSS2), the serine protease inhibitor Kazal type 1 (SPINK1), and the cystic fibrosis transmembrane conductance regulator (CFTR)--have also been found to be associated with chronic pancreatitis (idiopathic and hereditary). Genetic testing should only be performed in carefully selected patients by direct DNA sequencing, and antenatal diagnosis should not be encouraged. Treatment focuses on enzyme and nutritional supplementation, pain management, pancreatic diabetes, and local organ complications such as pseudocysts and bile-duct or duodenal obstruction. The disease course and prognosis of patients with HCP is unpredictable. The risk of pancreatic cancer is elevated. Therefore, HCP patients should strongly avoid environmental risk factors for pancreatic cancer.