Lack of R117H mutation in the cationic trypsinogen gene in patients with tropical pancreatitis from Bangladesh

International Consensus Guidelines for Risk Factors in Chronic Pancreatitis. Recommendations from the working group for the international consensus guidelines for chronic pancreatitis in collaboration with the International Association of Pancreatology, the American Pancreatic Association, the Japan Pancreas Society, and European Pancreatic Club

BACKGROUND

Chronic pancreatitis (CP) is a complex inflammatory disease with remarkably impaired quality of life and permanent damage of the pancreas. This paper is part of the international consensus guidelines on CP and presents the consensus on factors elevating the risk for CP.

METHODS

An international working group with 20 experts on CP from the major pancreas societies (IAP, APA, JPS, and EPC) evaluated 14 statements generated from evidence on four questions deemed to be the most clinically relevant in CP. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to evaluate the level of evidence available per statement. To determine the level of agreement, the working group voted on the 14 statements for strength of agreement, using a nine-point Likert scale in order to calculate Cronbach's alpha reliability coefficient.

RESULTS

Strong consensus and agreement were obtained for the following statements: Alcohol, smoking, and certain genetic alterations are risk factors for CP. Past history, family history, onset of symptoms, and life-style factors including alcohol intake and smoking history should be determined. Alcohol consumption dose-dependently elevates the risk of CP up to 4-fold. Ever smokers, even smoking less than a pack of cigarettes per day, have an increased risk for CP, as compared to never smokers.

CONCLUSIONS

Both genetic and environmental factors can markedly elevate the risk for CP. Therefore, health-promoting lifestyle education and in certain cases genetic counselling should be employed to reduce the incidence of CP.

Chronic pancreatitis and exocrine insufficiency

The evaluation, management, and follow-up of patients with chronic pancreatitis (CP) can be simple, but it can also be complex, so having a good referral network of subspecialists experienced in this field is essential. Identifying the cause of CP requires a systematic review of the many potential causes when the cause is not obvious. The identification of patients with autoimmune CP is particularly important because treatment with steroids may be effective. Alterations in pain or other symptoms in patients with CP should not be attributed to worsening disease before evaluations for complications including malignancy are done.

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.

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.

Tropical calcific pancreatitis and its association with CTRC and SPINK1 (p.N34S) variants

BACKGROUND

Tropical calcific pancreatitis (TCP) is a relatively common form of chronic pancreatitis in parts of Asia and Africa. The SPINK1 variant p.N34S is strongly associated with TCP, but other genetic factors remain to be defined. Chymotrypsinogen C (CTRC) degrades trypsinogen and loss-of-function variants have been found in European patients with chronic pancreatitis. Preliminary data indicate that CTRC might increase the risk for TCP.

MATERIALS AND METHODS

We selected 150 Indian TCP patients and 150 Indian controls to perform mutational screening of the complete coding region of CTRC and exon 3 of SPINK1. We performed in-silico analysis and functional studies of novel CTRC variants.

RESULTS

We identified eight variants among this sample. Three were synonymous and c.180 C>T was significantly enriched in patients (odds ratio=2.09; 95% confidence interval=1.19-3.67; P=0.03). We identified a novel nonsynonymous CTRC (p.G61R) variant in one of 146 patients (0.7%), but absent from controls. In-silico analysis showed that this variant affected a conserved residue, and functional analysis showed that p.G61R results in a complete loss of CTRC secretion from transiently transfected human embryonic kidney 293T cells. SPINK1 p.N34S was present in 31.8% of patients compared with 4.7% in controls, there was no significant cosegregation with CTRC variants.

CONCLUSION

The contribution of CTRC variants to TCP is relatively small, but the identification of novel loss-of-function variants (p.G61R) underscores the importance of the trypsinogen pathway in causing TCP.

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.

Divergent roles of SPINK1 and PRSS2 variants in tropical calcific pancreatitis

BACKGROUND/AIMS

Tropical calcific pancreatitis (TCP) refers to a type of idiopathic pancreatitis prevalent in Asia. The trypsin inhibitor (SPINK1) N34S variant partially explains the genetic susceptibility to TCP. As anionic trypsinogen (PRSS2) G191R protects against chronic pancreatitis in Europeans, we investigated whether this variant protects from TCP in Indians.

METHODS

We enrolled 174 patients and 794 controls from two Indian tertiary care referral hospitals. We analyzed PRSS2 and SPINK1 variants by melting curve analysis, allele-specific discrimination assay, and sequencing.

RESULTS

G191R was detected in 1 TCP patient (0.6%) compared to 13 controls (1.6%; OR 0.27, 95% CI 0.03-2.1; p = 0.33). SPINK1 N34S was enriched in the TCP population 67/174 (38.5%) compared to controls 10/234 (4.3%; OR 14, 95% CI 6.9-28.3; p < 0.001).

CONCLUSION

G191R PRSS2 is a rare allele in the Indian population and the data suggest a nonsignificant trend towards a protective effect. N34S SPINK1 represents the major genetic risk factor in TCP.

Trypsinogen mutations in pancreatic disorders

There are multiple PRSS1 mutations described in hereditary pancreatitis but only a minority of these are clinically relevant. The two most frequent point mutations are in exon 2 (N29I) and exon3 (R122H), found in diverse racial populations. Both mutations result in early onset pancreatitis but the mechanism underlying this phenotype is unclear. The frequency of these mutations in such diverse populations suggests they have spontaneously occurred many times. The origin of the major mutations may be explained by gene conversions, accounting for multiple founders. The implications are discussed in terms of mechanism of action of the mutations and clinical presentation.

A Thai family with hereditary pancreatitis and increased cancer risk due to a mutation in PRSS1 gene

AIM: To investigate mutation of serine protease 1–cationic trypsinogen (CT, PRSS1) gene in members of a Thai family with hereditary pancreatitis and pancreatic cancer.

METHODS: Polymerase chain reaction and direct sequencing were performed to analyze the PRSS1 gene in two members of the family affected by pancreatitis. Allele specific amplification (ASA) method was then developed to detect the mutation of the PRSS1 gene in all available members of the family and normal control subjects.

RESULTS: A cytosine (C) to thymine (T) mutation at position 2441 (g.2441C>T) of the PRSS1 gene, which results in a substitution of arginine by cysteine at position 116 (R116C) of CT, was identified by direct sequencing in both clinically affected members of the family but was not found in the unaffected member. This mutation, which might be arising from deamination of methylated cytosine in CpG dinucleotide of codon 116 (CGT>TGT), was also detected by the ASA method in the two affected members and a proband’s brother but was not observed in unaffected members and 54 normal control subjects.

CONCLUSION: Autosomal dominant pancreatitis with increased cancer risk in the studied Thai family is most likely due to missense (R116C) mutation in the PRSS1 gene.

Cationic Trypsinogen Mutations and Pancreatitis

The discovery of PRSS 1 mutations in hereditary pancreatitis and analysis of how the genotype affects the presentation and progression of hereditary pancreatitis has led to a better understanding of the pathophysiology of the disease. Patients with hereditary pancreatitis present with symptoms at an early age and have a significant lifetime risk for the development of endocrine and exocrine insufficiency, albeit at a later stage than patients with either idiopathic or alcoholic chronic pancreatitis. There are distinct phenotypic differences between hereditary pancreatitis and with other types of pancreatitis. As many as 80% of patients with symptomatic hereditary pancreatitis have an underlying causative PRSS1 mutation; there are, however, few significant phenotypic differences between these PRSS1 mutations. TheR122H mutation is the most common PRSS1 mutation observed, and patients with the R122H mutation present earlier. This, however, does not necessarily translate into a more aggressive disease with respect to complications of chronic pancreatitis. Indeed, the age of presentation of symptoms may be a poor surrogate for predicting outcome, as inherited disorders of trypsinogen may cause subclinical attacks of pancreatitis, which ultimately lead to pancreatic destruction and dysfunction. All patients, irrespective of whether they carry a PRSS1 mutation, are at significant risk of developing pancreatic ductal adenocarcinoma. The risk appears to be insignificant below the age of 40 years, but it increases incrementally thereafter. Significantly, the risk of pancreatic cancer is not related to PRSS1 mutation type and does not appear to be related to the mode of inheritance. The role of SPINK1 mutations in modifying the expression of PRSS1mutations is unclear but appears to be of clinical importance. It is unlikely that they act as causative mutations per se, at least in the Western form of the disease. Additionally, they do not appear to have an impact on the penetrance of PRSS1 gene mutations in hereditary pancreatitis.

Cationic trypsinogen mutations and pancreatitis

The discovery of PRSS1 mutations in hereditary pancreatitis and analysis of how the genotype affects the presentation and progression of hereditary pancreatitis has led to a better understanding of the pathophysiology of the disease. Patients with hereditary pancreatitis present with symptoms at an early age and have a significant lifetime risk for the development of endocrine and exocrine insufficiency, albeit at a later stage than patients with either idiopathic or alcoholic chronic pancreatitis. There are distinct phenotypic differences between hereditary pancreatitis and with other types of pancreatitis. As many as 80% of patients with symptomatic hereditary pancreatitis have an underlying causative PRSS1 mutation; there are, however, few significant phenotypic differences between these PRSS1 mutations. The R122H mutation is the most common PRSS1 mutation observed, and patients with the R122H mutation present earlier. This, however, does not necessarily translate into a more aggressive disease with respect to complications of chronic pancreatitis. Indeed, the age of presentation of symptoms may be a poor surrogate for predicting outcome, as inherited disorders of trypsinogen may cause subclinical attacks of pancreatitis, which ultimately lead to pancreatic destruction and dysfunction. All patients, irrespective of whether they carry a PRSS1 mutation, are at significant risk of developing pancreatic ductal adenocarcinoma. The risk appears to be insignificant below the age of 40 years, but it increases incrementally thereafter. Significantly, the risk of pancreatic cancer is not related to PRSS1 mutation type and does not appear to be related to the mode of inheritance. The role of SPINK1 mutations in modifying the expression of PRSS1 mutations is unclear but appears to be of clinical importance. It is unlikely that they act as causative mutations per se, at least in the Western form of the disease. Additionally, they do not appear to have an impact on the penetrance of PRSS1 gene mutations in hereditary pancreatitis.

Survey on chronic pancreatitis in the Asia-Pacific region

BACKGROUND AND AIMS

A survey was conducted of chronic pancreatitis (CP) in different countries in the Asia-Pacific region. The main objective of the survey was to generate a database containing information regarding the prevalence, etiology, clinical presentation, diagnostic work-up, and management of CP in the Asia-Pacific region.

METHODS

Data were collected from seven countries using a structured questionnaire. Expert participants were asked to respond to the questionnaire based on the data of patients with CP studied in their centers.

RESULTS

The prevalence of CP was found to be very high in southern India (114-200/100 000 population), in contrast to the low reported rate of 4.2/100 000 population in Japan. Alcohol was the most common etiological factor in Australia (95%) and Japan (54%) while idiopathic pancreatitis was the most common type in India (tropical pancreatitis) and China, accounting for approximately 70% of all cases of CP. Pain was the most common clinical feature. Diabetes and steatorrhea were uncommon. With regard to the diagnosis of CP, all the experts believed that a patient could be diagnosed as having CP in the presence of any one or more of the following: ductal changes on endoscopic retrograde cholangiopancreatography, a positive secretin test, pancreatic calcification, and endosonographic abnormalities suggestive of CP. Most experts suggested pancreatic enzymes and analgesics as initial medical therapy for pain relief in CP. Endotherapy was suggested as the therapy of choice if medical therapy failed. Surgery was offered only after the failure of endotherapy. Most experts agreed that research should focus on genetic abnormalities in CP and the role of endotherapy for pain relief.

CONCLUSION

The survey brought out the prevalent types and presentation of CP, common management practices, and also the shortcomings in the existing knowledge of CP in the Asia-Pacific region. These findings might help focus attention on the research priorities for CP in this region.

Comparison of histological features and inflammatory cell reaction in alcoholic, idiopathic and tropical chronic pancreatitis

BACKGROUND

There is increasing evidence that immune mechanisms may be crucial in the development of alcoholic chronic pancreatitis. However, it is not known whether differences in underlying aetiology influence the inflammatory reaction in patients with chronic pancreatitis. The histological features and the pattern of inflammatory cell infiltration were studied in three aetiological forms of chronic pancreatitis: alcoholic, idiopathic and tropical pancreatitis.

METHODS

Forty-three patients, ten with alcoholic, 12 with idiopathic and 21 with tropical chronic pancreatitis, were evaluated for the pattern of pancreatic inflammatory cell infiltration and histological features. Ten organ donors served as controls. Haematoxylin and eosin-stained tissue sections were used for histological evaluation. For immunohistochemical characterization of the inflammatory reaction, four antibodies-CD4, CD8, CD45 and CD68-were used. Quantitative evaluation of the various cell infiltrates was performed with computer-assisted image analysis. The inflammatory cell infiltration pattern was also evaluated.

RESULTS

The degree of endophlebitis and the overall density of plasma cells were greater in tropical than in alcoholic chronic pancreatitis. The grade of intralobular fibrosis was significantly higher in tropical chronic pancreatitis compared with the idiopathic form. No significant quantitative differences in the specific cellular infiltrates (CD4, CD8, CD45, CD68) were observed in the three different groups. However, the perivascular inflammation number score was significantly higher in alcoholic compared with idiopathic pancreatitis (P = 0.037), and the perivascular inflammation area score was significantly lower in idiopathic than in alcoholic (P = 0.024) or tropical (P = 0.020) pancreatitis.

CONCLUSION

Different aetiological forms of chronic pancreatitis result in similar histological features and a comparable inflammatory cell reaction, indicating that the disease, independent of the underlying aetiology, reaches a common immunological stage beyond which it appears to progress as a single distinctive entity.

Chronic pancreatitis

PURPOSE OF REVIEW

We are beginning to better understand the causes of chronic pancreatitis. This knowledge will hopefully lead to better diagnosis and treatment and abandonment of ill-conceived treatments. This review highlights contributions that moved the field toward these goals in the past year.

RECENT FINDINGS

Small steps have been made toward a better understanding of the molecular basis, particularly genetic causes, of the forms of chronic pancreatitis. Investigation of the role of stellate cells, an essential component of the fibrosis of chronic pancreatitis, has led to the finding that lovastatin inhibits stellate cell activation and could surface as a novel treatment of chronic pancreatitis. The clinical description of autoimmune pancreatitis has led to the realization that steroids are effective treatment for this form of chronic pancreatitis. Other treatments such as extracorporeal shock wave lithotripsy and endoscopic treatments have not been proved, because no controlled studies support these treatments over other treatments. The diagnosis of chronic pancreatitis may be enhanced by the new imaging technique of electronic pancreatoscopy whereby a 2.1-mm diameter scope can be advanced into the pancreatic duct through a duodenoscope. However, the data are too preliminary at this time to advocate this imaging procedure. A potential new endoscopic pancreatic function test may lead to more widespread use of function testing, but this test is not perfected and also cannot be advised for use at present.

SUMMARY

Ongoing basic and clinical research this past year has further characterized the genetic, molecular, and clinical aspects of chronic pancreatitis: efforts that may translate into novel therapies, once well-designed, controlled studies have been performed.

Genetic factors in pancreatitis

A number of genetic mutations have recently been identified that appear to be important in the development of pancreatitis. Point mutations in the cationic trypsinogen gene are capable of initiating pancreatitis. These mutations also provide important insights into the pathophysiology of acute pancreatitis and into potential connections between acute and chronic pancreatitis. Mutations in the genes encoding for the pancreatic secretory trypsin inhibitor and the cystic fibrosis transmembrane conductance regulator more likely work in concert with other genes and environmental factors in affecting disease susceptibility. Although the subject so far has received only a limited amount of study, genetic polymorphisms in a wide range of genes relating to pancreatic function and to regulation of inflammation are likely to play major roles in determining each individual's susceptibility to developing pancreatitis, and its severity if it does develop.

Tropical calcific pancreatitis: strong association with SPINK1 trypsin inhibitor mutations

BACKGROUND & AIMS

Tropical calcific pancreatitis (TCP) is a chronic pancreatitis unique to developing countries in tropical regions. The cause of TCP is obscure. Whereas environmental factors, such as protein energy malnutrition and ingestion of cassava, have been implicated, a genetic predisposition to the disease also may be important. In the present study we report on mutations in the serine protease inhibitor, Kazal type 1 (SPINK1) gene in north Indian patients with TCP.

METHODS

We studied 66 unrelated TCP patients (44 men, 49 with diabetes, and 6 with family history of TCP), 25 relatives, and 92 healthy control subjects. Samples were analyzed for SPINK1 variants (-53C>T, L14P, N34S, P55S, and 272T>C) and cationic trypsinogen (PRSS1) variants (A16V, K23R, N29I, and R122H) by melting curve analysis.

RESULTS

Twenty-nine patients (44%) carried the N34S missense mutation, of whom 9 (14%) were homozygotes. In contrast, only 2 (2.2%) control subjects were N34S heterozygotes (prevalence ratio 20.2; 95% confidence interval 5.0-81.8; P < 0.0001 vs. TCP). The severity of pancreatitis did not differ between TCP patients with or without N34S, or among those heterozygous or homozygous for N34S. Among TCP patients with or without diabetes, the frequency of N34S carriers (43% vs. 47%) and N34S homozygotes (14% vs. 12%) was similar.

CONCLUSIONS

TCP is highly associated with the SPINK1 N34S mutation. The high prevalence of N34S in TCP patients with and without diabetes suggests that these 2 subtypes have a similar genetic predisposition. The genetic predisposition to TCP resembles, at least in part, the idiopathic chronic pancreatitis found in industrialized countries.

SPINK1 is a susceptibility gene for fibrocalculous pancreatic diabetes in subjects from the Indian subcontinent

Fibrocalculous pancreatic diabetes (FCPD) is a secondary cause of diabetes due to chronic pancreatitis. Since the N34S variant of the SPINK1 trypsin inhibitor gene has been found to partially account for genetic susceptibility to chronic pancreatitis, we used a family-based and case-control approach in two separate ethnic groups from the Indian subcontinent, to determine whether N34S was associated with susceptibility to FCPD. Clear excess transmission of SPINK1 N34S to the probands with FCPD in 69 Bangladeshi families was observed (P<.0001; 20 transmissions and 2 nontransmissions). In the total study group (Bangladeshi and southern Indian) the N34S variant was present in 33% of 180 subjects with FCPD, 4.4% of 861 nondiabetic subjects (odds ratio 10.8; P<.0001 compared with FCPD), 3.7% of 219 subjects with type 2 diabetes, and 10.6% of 354 subjects with early-onset diabetes (aged <30 years) (P=.02 compared with the ethnically matched control group). These results suggest that the N34S variant of SPINK1 is a susceptibility gene for FCPD in the Indian subcontinent, although, by itself, it is not sufficient to cause disease.

SPINK1/PSTI mutations are associated with tropical pancreatitis and type II diabetes mellitus in Bangladesh

BACKGROUND & AIMS

Tropical pancreatitis, including tropical calcific pancreatitis and fibrocalculous pancreatic diabetes, is endemic in parts of Asia and Africa. In a preliminary study, we found serine protease inhibitor, Kazal type 1 (SPINK1) mutations in 6 of 8 patients with fibrocalculous pancreatic diabetes in Bangladesh. A more extensive investigation of patients with pancreatic diseases in Bangladesh, including non-insulin-dependent diabetes mellitus, was undertaken.

METHODS

Patients with fibrocalculous pancreatic diabetes (n = 22), tropical calcific pancreatitis (n = 15), and non-insulin-dependent diabetes mellitus (n = 43) and controls (n = 76) from Bangladesh were studied. DNA was extracted, and the SPINK1 gene was sequenced in all patients and 50 controls. Exon 3 was sequenced in an additional 26 controls.

RESULTS

SPINK1 N34S mutations appeared in 1 of 76 controls (1.3%), 12 of 22 patients with fibrocalculous pancreatic diabetes (55%; odds ratio, 83; P < 0.00001), 3 of 15 with tropical calcific pancreatitis (20%; odds ratio, 11.2; P = 0.04), and 6 of 43 with non-insulin-dependent diabetes mellitus (14%; odds ratio, 11.9; P = 0.009). P55S was present in 2 of 76 controls (3%) and in 1 of 22 patients with fibrocalculous pancreatic diabetes (5%; P = not significant). A novel Y54H (160T>C) mutation was identified in 1 of 15 tropical calcific pancreatitis patients.

CONCLUSIONS

In Bangladesh, the SPINK1 N34S mutation increases the risk of several forms of pancreatic disease, including fibrocalculous pancreatic diabetes, tropical calcific pancreatitis, and non-insulin-dependent diabetes mellitus.

SPINK1/PSTI mutations are associated with tropical pancreatitis in Bangladesh. A preliminary report

BACKGROUND/AIMS

Tropical pancreatitis (TP) refers to a severe type of idiopathic chronic pancreatitis that develops in children in tropical regions of Africa and southern Asia. Phenotypically TP is subdivided into fibrocalculous pancreatic diabetes (FCPD) and tropical calcific pancreatitis without diabetes mellitus (TCP). Recently an association was identified between idiopathic pancreatitis in the USA and Europe and mutations in the serine protease inhibitor, Kazal type 1 (SPINK1) gene (previously termed pancreatic secretory trypsin inhibitor, PSTI). Our aim was to determine if either form of TP has a genetic basis.

METHODS

We studied 8 well-characterized patients from Bangladesh with FCPD, 4 with TCP and 4 controls without pancreatic disease. The entire SPINK1 gene was sequenced in these patients.

RESULTS

We detected two disease-associated SPINK1 mutations (N34S/IVS1 - 37T > C and IVS3 + 2T > C) in 6 of 8 patients from Bangladesh with FCPD but not in 4 patients with TCP (p < 0.03) or 4 controls (p < 0.03).

CONCLUSIONS

We conclude that SPINK1 mutations are associated with FCPD in Bangladesh. Since SPINK1 mutations in Europeans and North Americans are associated with idiopathic chronic pancreatitis that is phenotypically different from FCPD, we further conclude that mutated SPINK1 markedly increases the risk of developing a variety of pancreatic diseases possibly through a chronic elevation of active trypsin within the pancreas.

SPINK1 mutations are associated with multiple phenotypes

Mutations in the gene encoding for the pancreatic secretory trypsin inhibitor or serine protease inhibitor, Kazal type I (SPINK1) have been associated with different entities of chronic pancreatitis. While there is no doubt about the involvement of SPINK1 mutations in pancreatic inflammatory disease, much controversy has arisen regarding which alterations are associated with disease and what type of disease model should be applied when the SPINK1 gene is examined. This article presents the existing data on SPINK1 mutations in idiopathic chronic pancreatitis, familial pancreatitis, hereditary pancreatitis and tropical pancreatitis. The possible role of SPINK1 mutations and polymorphisms in pancreatic disease is discussed.

Tropical pancreatitis

Tropical pancreatitis is an uncommon cause of acute, and often chronic, relapsing pancreatitis. Patients present with abdominal pain, weight loss, pancreatic calcifications, and glucose intolerance or diabetes mellitus. Etiologies include a protein-calorie malnourished state, a variety of exogenous food toxins, pancreatic duct anomalies, and a possible genetic predisposition. Chronic cyanide exposure from the diet may contribute to this disease, seen often in India, Asia, and Africa. The pancreatic duct of these patients often is markedly dilated, and may contain stones, with or without strictures. The risk of ductal carcinoma with this disease is accentuated. Treatment may be frustrating, and may include pancreatic enzymes, duct manipulations at endoscopic retrograde cholangiopancreatography, octreotide, celiac axis blocks for pain control, or surgery via drainage and/or resection.

Chronic pancreatitis: Asia-Pacific consensus report

Current knowledge about chronic pancreatitis (CP) is limited and there is a particular dearth of information about the entity known as tropical pancreatitis. A consensus working party was convened by the Trustees of the Journal of Gastroenterology and Hepatology Foundation to conduct a systematic investigation into available evidence about the epidemiology, etiopathogenesis, diagnosis and management of CP. A literature search and formal survey of international experts in the field were used to assemble reliable evidence about these issues. The present review summarizes the results of the working party's findings and presents a series of practice guidelines to improve diagnosis, investigation and treatment of patients with CP, particularly those in the Asia-Pacific region. Areas for further research have also been identified.

[Tropical chronic pancreatitis in a young patient]

Tropical chronic pancreatitis is a form of idiopathic chronic pancreatitis that has not previously been described in Spain. Typically it is related to dietary factors and malnutrition, although genetic factors may also play a significant role in the development of the disease. We report a case of chronic tropical pancreatitis in a 27-year-old woman from the Dominican Republic domiciled in Spain since 1992. The patient was admitted to our hospital for acute pancreatitis that fulfilled the diagnostic criteria (clinical and radiological) for chronic tropical pancreatitis. This case has led us to review this uncommon entity. Because of the increasing number of immigrants from tropical countries, chronic tropical pancreatitis will probably need to be taken into account in the differential diagnosis of chronic pancreatitis in our patients.

Mutational screening of the cationic trypsinogen gene in a large cohort of subjects with idiopathic chronic pancreatitis

Several missense mutations, including R122H, N29I, K23R, A16V and D22G, in the cationic trypsinogen gene (PRSS1), have been associated with certain forms of hereditary pancreatitis (HP). Their occurrence in the idiopathic chronic pancreatitis (ICP) and whether novel mutations could be identified in PRSS1 remain to be further evaluated. These were addressed by the mutational screening of the entire coding sequence and the intronic/exonic boundaries of the PRSS1 gene in 221 ICP subjects, using a previously established denaturing gradient gel electrophoresis technique. Among the known PRSS1 mutations, only the R122H was detected in a single subject and the A16V in two subjects in the cohort, strengthening that HP-associated PRSS1 mutations are rare in ICP. Additional missense mutations, including P36R, E79K, G83E, K92N and V123M, were identified once separately. By analogy with the known PRSS1 mutations, predisposition to pancreatitis by some of them, particularly the V123M autolysis cleavage site mutation, is suspected. Functional analysis is expected to clarify their possible medical consequences.

Chronic pancreatitis: diagnosis, classification, and new genetic developments

The utilization of recent advances in molecular and genomic technologies and progress in pancreatic imaging techniques provided remarkable insight into genetic, environmental, immunologic, and pathobiological factors leading to chronic pancreatitis. Translation of these advances into clinical practice demands a reassessment of current approaches to diagnosis, classification, and staging. We conclude that an adequate pancreatic biopsy must be the gold standard against which all diagnostic approaches are judged. Although computed tomography remains the initial test of choice for the diagnosis of chronic pancreatitis, the roles of endoscopic retrograde pancreatography, endoscopic ultrasonography, and magnetic resonance imaging are considered. Once chronic pancreatitis is diagnosed, proper classification becomes important. Major predisposing risk factors to chronic pancreatitis may be categorized as either (1) toxic-metabolic, (2) idiopathic, (3) genetic, (4) autoimmune, (5) recurrent and severe acute pancreatitis, or (6) obstructive (TIGAR-O system). After classification, staging of pancreatic function, injury, and fibrosis becomes the next major concern. Further research is needed to determine the clinical and natural history of chronic pancreatitis developing in the context of various risk factors. New methods are needed for early diagnosis of chronic pancreatitis, and new therapies are needed to determine whether interventions will delay or prevent the progression of the irreversible damage characterizing end-stage chronic pancreatitis.

Pancreatitis in fibrocalculous pancreatic diabetes mellitus is not associated with common mutations in the trypsinogen gene

BACKGROUND

A distinct type of pancreatitis associated with diabetes, termed fibrocalculous pancreatic diabetes (FCPD), has been reported in tropical developing countries including Bangladesh. The molecular basis for autosomal dominant hereditary pancreatitis (HP) has recently been attributed to mutations in exons 2 and 3 of the trypsinogen gene. We have investigated the hypothesis that mutations in the aforementioned exons of this gene might also predispose to FCPD.

METHODS

Seventy Bangladeshi and 50 South Indian unrelated FCPD patients and seven South Indian families with FCPD probands were studied. Pancreatic calcification was confirmed by abdominal X-ray, ultrasound and/or ERCP. Established mutations of exons 2 and 3 of the trypsinogen gene were studied in these subjects by PCR-RFLP analysis and DNA sequencing.

RESULTS

The mutations found in hereditary pancreatitis were not observed in this collection of FCPD subjects, and complete DNA sequencing of exons 2 and 3 of the fourth cationic trypsinogen gene also excluded any new mutations.

CONCLUSIONS

These results indicate that chronic pancreatitis of FCPD is unlikely to be caused by common mutations in the trypsinogen gene.

Hereditary pancreatitis and mutations of the cationic trypsinogen gene

BACKGROUND

Mutations of the cationic trypsinogen gene have been detected in hereditary pancreatitis. This article reviews current understanding of their function and clinical significance.

METHODS

An unrestricted Medline search was conducted using the key words hereditary pancreatitis and 'cationic trypsinogen . Additional material was obtained from references cited in original papers and recently published abstracts of meetings.

RESULTS AND CONCLUSION

Cationic trypsinogen mutations have been identified in most, but not all, families with hereditary pancreatitis. This confirms existing evidence that premature trypsinogen activation plays a central role in the pathogenesis of human pancreatitis. Patients currently clinically defined as having hereditary pancreatitis should be screened for the presence of cationic trypsinogen mutations. A subgroup of patients with non-hereditary pancreatitis may also benefit from being screened for these mutations. Patients with hereditary pancreatitis should be entered into prospective, multicentre trials investigating secondary screening for pancreatic cancer. Gene therapy for hereditary pancreatitis is beyond current technological capability but remains a future therapeutic prospect for this often debilitating condition.