Analysis of PRSS1 and SPINK1 mutations in Korean patients with idiopathic and familial pancreatitis

WITHDRAWN: Clinical interpretation of PRSS1 gene variants in patients with pancreatitis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 The duplicate article has therefore been withdrawn.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

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.

Genetic Abnormalities in Pancreatitis: An Update on Diagnosis, Clinical Features, and Treatment

Several pancreatitis susceptibility genes have been identified to date. A relationship between a mutation in the cationic trypsinogen (protease serine 1, PRSS1) gene and hereditary pancreatitis (HP) was first identified in 1996. Currently, HP has been defined as either two or more individuals within a family exhibiting pancreatitis for two or more generations, or pancreatitis linked to mutation of the PRSS1 gene. In 2000, a mutation in the serine protease inhibitor gene (Kazal type 1: SPINK1) was reported to be related to sporadic pancreatitis of unknown etiology. This paper reviews and summarizes the current published data on the pancreatitis susceptibility genes, mainly PRSS1 and SPINK1 genes, and introduces a diagnostic and therapeutic approach for dealing with patients with these gene mutations. Patients with these genetic predispositions, both children and adults, have often been initially diagnosed with idiopathic acute pancreatitis, in approximately 20-50% of pediatric cases and 28-80% of adult cases. In such patients, where the etiology is unknown, genetic testing, which requires pre-test and post-test genetic counselling, may prove helpful. Patients with chronic pancreatitis (CP) due to SPINK1 gene mutation and HP patients have a potentially high risk of pancreatic exocrine insufficiency, diabetes mellitus, and, of particular importance, pancreatic cancer. Thus, these patients require careful long-term follow-up and management. Specifically, symptomatic CP patients often need endoscopic therapy or surgery, often following a step-up approach beginning with endoscopic therapy and progressing to surgery if necessary, which is similar to the therapeutic approach for patients with CP due to other etiologies. It is important that clinicians are aware of the characteristics of patients with pancreatitis susceptibility genetic abnormalities.

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.

Meta-analysis of the impact of the SPINK1 c.194 + 2T > C variant in chronic pancreatitis

BACKGROUND AND AIMS

The SPINK1 c.194 + 2T > C variant has been increasingly recognized as an important risk factor for chronic pancreatitis (CP). However, there is no clear agreement on its contribution to different ethnicities and CP etiologies. To address this issue, a meta-analysis of literature was performed.

METHODS

Studies addressing the presence of the SPINK1 c.194 + 2T > C variant in CP patients and controls were retrieved from the PubMed, EMBASE and Cochrane databases. Initial analysis included all CP patients, followed by subgroup analyses for East Asian and non-East Asian patients, and for idiopathic CP (ICP) and non-ICP.

RESULTS

A total of 13 studies were retrieved for analysis, comprising 2097 cases and 4019 controls. There were 126 cases (10.01%) carrying the SPINK1 c.194 + 2T > C variant in cases, while only two controls were carriers (0.05%). Overall, the variant was significantly associated with an increased risk of CP (OR = 25.73). In the subgroup, the variant was significantly associated with increased risk of CP in East Asians (OR = 73.16), and in non-East Asians (OR = 10.21). Further, the contribution of the variant in ICP (OR = 35.31) was found to be higher than in non-ICP (25.75).

CONCLUSIONS

The SPINK1 c.194 + 2T > C variant is a strong risk factor for CP, especially in East Asian patients with ICP.

A New Insight into Chronic Pancreatitis

Chronic pancreatitis (CP) is a pancreatic disease with poor prognosis characterized clinically by abdominal pain, morphologically by pancreatic stones/calcification, duct dilatation and atrophy, and functionally by pancreatic exocrine and endocrine insufficiency. CP is also known as a risk factor for the development of pancreatic cancer. CP has long been understood based on a fixed disease concept deduced from the clinical and morphological features of the end-stage disease. However, identification of causal genes for hereditary pancreatitis and success in the isolation and culture of pancreatic stellate cells have advanced the understanding of the underlying pathological mechanisms, the early-stage pathophysiology, and the mechanisms behind pancreatic fibrosis. These advances have led to moves aimed at improving patient prognosis through prevention of disease progression by early diagnosis and early therapeutic intervention. The strategy for preventing disease progression has included a proposal for diagnostic criteria for early CP and introduction of a new definition of CP in consideration of the pathological mechanisms. Our group has been committed deeply to these studies and has provided a large amount of information to the world.

Genetic Risk in Chronic Pancreatitis: The Trypsin-Dependent Pathway

Genetic investigations have provided unique insight into the mechanism of chronic pancreatitis in humans and firmly established that uncontrolled trypsin activity is a central pathogenic factor. Mutations in the PRSS1, SPINK1, and CTRC genes promote increased activation of trypsinogen to trypsin by stimulation of autoactivation or by impairing protective trypsinogen degradation and/or trypsin inhibition. Here we review key genetic and biochemical features of the trypsin-dependent pathological pathway in chronic pancreatitis.

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.

Genetic mutations in SPINK1, CFTR, CTRC genes in acute pancreatitis

Background

Explanation of the ultimate causes of acute and chronic pancreatitis is challenging. Hence, it is necessary to seek various etiological factors, including genetic mutations that may be of importance in triggering recurrence and progression of acute to chronic pancreatitis. The aim of this study was to determine the frequency of genetic mutations in patients with acute pancreatitis and to investigate their relationship with the etiology and clinical course.

Methods

The study included 221 patients treated for acute pancreatitis and 345 healthy subjects as a control group. Peripheral blood samples were collected from each study participant and genomic DNA was isolated. Genotyping of common mutations in the SPINK1 (p.N34S and p.P55S) and CTRC (p.I259V, p.V235I, p.K247_R254del, p.E225A) genes was performed using the high-resolution melting method. Mutations in the CFTR p.F508del (delF508_CTT) were genotyped using allele-specific amplification polymerase chain reaction. All detected mutations were confirmed with direct capillary DNA sequencing.

Results

Mutations in SPINK 1, CFTR and CTRC were detected in 6.3 %, 2.3 % and 1.8 % of patients with acute pancreatitis versus 3.2 %, 3.8 % and 1.2 % of volunteers in the control group. No relationship was found between the detected mutations and severity of acute pancreatitis: mild acute pancreatitis, mutation of CFTR in 4 (2.8 %) and CTRC in 2 (1.4 %) patients; severe acute pancreatitis, mutation of CFTR and CTRC in 1 (2.6 %) case each. The SPINK1 mutation was significantly more frequent in 8 (10.4 %) severe cases than in 6 (4.2 %) mild cases (P < 0.05), and was observed in 5/70 (7.1 %) patients with alcohol-related AP, 5/81 (6.2 %) with biliary AP, and 4/63 (6.3 %) in those without any established cause of the disease.

Conclusions

Mutation p.N34S in SPINK1 may predispose patients to acute pancreatitis, especially in those abusing alcohol, and may promote a more severe course of the disease.

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.

Genetics of pancreatitis: the 2014 update

Chronic pancreatitis is a progressive inflammatory disease in which pancreatic secretory parenchyma is destroyed and replaced by fibrous tissue, eventually leading to malnutrition and diabetes. Alcohol is the leading cause in Western countries, but genetic factors are also implicated. Since the identification of mutations in the cationic trypsinogen (PRSS1) gene as a cause of hereditary pancreatitis in 1996, we have seen great progress in our understanding of the genetics of pancreatitis. It has been established that mutations in the genes related to the activation and inactivation of trypsin(ogen) such as PRSS1, serine protease inhibitor Kazal type 1 (SPINK1) and chymotrypsin C (CTRC) genes are associated with pancreatitis. In 2013, carboxypeptidase A1 (CPA1) was identified as a novel pancreatitis susceptibility gene. Endoplasmic reticulum stress in pancreatic acinar cells resulting from the mis-folding of mutated pancreatic enzymes has been shown to act as a novel mechanism underlying the susceptibility to pancreatitis. In Japan, the nationwide survey revealed 171 patients (96 males and 75 females) with hereditary pancreatitis in 59 families based on the European Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer criteria. Because about 30% of families with hereditary pancreatitis do not carry mutations in any of the known pancreatitis susceptibility genes, other yet unidentified genes might be involved. Next generation sequencers can perform billions of sequencing reactions with a read length of 150-250 nucleotides. Comprehensive analysis using next generation sequencers will be a promising strategy to identify novel pancreatitis-associated genes and further clarify the pathogenesis of pancreatitis.

Comprehensive screening for PRSS1, SPINK1, CFTR, CTRC and CLDN2 gene mutations in Chinese paediatric patients with idiopathic chronic pancreatitis: a cohort study

OBJECTIVE

Genetic alterations may contribute to chronic pancreatitis (CP) in Chinese young patients. This study was designed to investigate mutations of cationic trypsinogen (PRSS1), pancreatic secretory trypsin inhibitor or serine protease inhibitor Kazal type 1 (SPINK1), cystic fibrosis transmembrane conductance regulator (CFTR), chymotrypsin C (CTRC) and CLDN2 genes and the copy number variations (CNVs) of PRSS1 and asses associations with the development of idiopathic CP (ICP) in Chinese children.

DESIGN

Retrospective.

SETTING

A single center.

PARTICIPANTS

75 ICP Chinese children (40 boys and 35 girls).

PRIMARY AND SECONDARY OUTCOME MEASURES

Mutations of PRSS1, SPINK1, CFTR, CTRC and CLDN2 genes and CNVs.

RESULTS

7 patients had heterozygous mutations in PRSS1, that is, N29I (n=1), R122H or R122C (n=6). The CNVs of PRSS1 in five patients had abnormal copies (1 copy (n=4), five copies (n=1)). 43 patients had IVS3+2T>C (rs148954387) (10 homozygous and 33 heterozygous) in SPINK1. None of the PRSS1 mutation patients carried a SPINK1 mutation. Frequency of PRSS1 and SPINK1 mutations was 9.3% and 57.3%, respectively, with an overall frequency of 66.6% (50/75). In addition, one patient had a novel deletion of CFTR (GCTTCCTA from c.500 to c.508 leading to the shortened polypeptide molecule via a stop codon). Another patient had a novel missense in CLDN2 exon 2 (c.592A>C mutation). Clinically, patients with SPINK1 mutations had a higher rate of pancreatic duct stones, pancreatic pseudocyst and pancreatic calcification than those without SPINK1 mutations (p<0.05).

CONCLUSIONS

SPINK1 mutations were more commonly associated with Chinese children with ICP. SPINK1 IVS3+2T>C mutation may play an important role in the pathogenesis of Chinese paediatric ICP. However, further study is needed to confirm and to investigate the role of these genes in the development of Chinese ICP.

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.

Chronic pancreatitis in India and Asia

Chronic pancreatitis (CP) is widely prevalent in Asian countries much more so in India and Japan. The phenotype of CP is somewhat similar to that reported from western countries. The prevalent types of CP are mainly idiopathic and alcohol related. Current evidence suggests that the term "tropical pancreatitis" used for idiopathic CP from India is a misnomer. Gallstones' association with CP reported from China remains controversial. There has been ample evidence that mutations in the SPNIK1 and CFTR genes are strongly associated with idiopathic CP in patients from different ethnic backgrounds. Oxidative stress is important in the pathophysiology and antioxidants have been shown to result in significant pain relief with CP. Home-made balanced diet is effective for treating malnutrition in patients with CP. Endoscopic therapy combined with ESWL may provide significant relief in patients with pancreatic ductal calculi/stricture. Surgery is quite effective in CP and may be better than endotherapy.

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 aspects of pancreatitis

Acute pancreatitis and chronic pancreatitis are complex inflammatory disorders of the pancreas with unpredictable severity, complications, and clinical courses. Growing evidence for genetic risk and modifying factors, plus strong evidence that only a minority of patients with these disorders are heavy alcohol drinkers, has revolutionized our concept of these diseases. Once considered a self-inflicted injury, pancreatitis is now recognized as a complex inflammatory condition like inflammatory bowel disease. Genetic linkage and candidate gene studies have identified six pancreas-targeting factors that are associated with changes in susceptibility to acute and/or chronic pancreatitis, including cationic trypsinogen (PRSS1), anionic trypsinogen (PRSS2), serine protease inhibitor Kazal 1 (SPINK1), cystic fibrosis transmembrane conductance regulator (CFTR), chymotrypsinogen C (CTRC) and calcium-sensing receptor (CASR). Patients with mutations in these genes are at increased risk of pancreatitis caused by a variety of stresses including hyperlipidemia and hypercalcemia. Multiple studies are reporting new polymorphisms, as well as complex gene x gene and gene x environmental interactions.