Mutations in the cystic fibrosis transmembrane regulator gene in patients with tropical calcific pancreatitis

Clinical profile and treatment outcome of chronic pancreatitis in children: a long-term follow-up study of 156 cases

AIM

There is a paucity of literature in pediatric chronic pancreatitis (CP) and most information is derived from adult literature. We, therefore, analyzed our experience of CP to look for clinical profile and long-term outcome.

METHODS

From January 2003 to December 2015, 156 consecutive children (≤18 years) diagnosed as CP were included. Their clinical profile, management, and follow-up data were retrieved. Genetic markers (PRSS1, SPINK1, and CFTR) were studied in 40 idiopathic cases.

RESULTS

The median age of the patients was 13 [inter-quartile range (IQR): 10-14] years (93 males) and 134 (86%) were idiopathic. Genetic mutations were found in 22/40 (55%) idiopathic cases. All but two presented with pain abdomen (episodic pain in 93.6%) and symptom duration was 12 (IQR: 6-24) months. There were two subsets; calcific (CCP) 68 (43.5%) and non-calcific (NCCP) 88 (56.5%). In CCP group, significantly more children had Cambridge grade 5 magnetic resonance cholangiopancreatography changes, low weight Z-score, and had continuous pain more compared to NCCP group. Over a median follow-up of 23 (IQR: 8-45.5) months, more children in CCP group had complications. Endoscopic therapy (done for persistent pain in 40) relieved pain in 52.5% of cases while medical therapy did so in 36% of cases.

CONCLUSION

Pediatric CP in Asia presents with episodic pain and genetic predisposition seems to be a major cause. There are two subsets; CCP and NCCP with former showing marked imaging changes, more often associated with malnutrition and complications. Endoscopic therapy for pain relief gives modest benefit but medical therapy is not encouraging.

Is acute recurrent pancreatitis in children a precursor of chronic pancreatitis? A long-term follow-up study of 93 cases

BACKGROUND/AIMS

In view of paucity of literature we analyzed our experience of acute recurrent pancreatitis (ARP) to study clinical profile and long-term outcome.

METHODS

Over 13 years, 93 consecutive children (≤18 years) diagnosed to have ARP were included in this study. Magnetic resonance cholangiopancreatography was done at baseline and on follow-up. Common mutations for serine-protease-inhibitor (SPINK1 N34S), protease inhibitor (PRSS1 R122S) and cystic fibrosis transmembrane conductance regulator (CFTR deltaF508, 5T) were studied in 22 idiopathic cases.

RESULTS

The median age of the children with ARP was 13 (10-14.5) years, 53 were males. Etiology included biliary in 14 (15%), pancreas divisum in 6 (7%), others in 3 (3.5%) and idiopathic in the remaining 70 (75%). SPINK1 mutation was found in 10/22 (45%) cases. Over a median follow-up of 25.5 (8.25-48) months, 37 (42%) of 88 (5 lost to follow-up) developed chronic pancreatitis (CP). On multivariate analysis idiopathic etiology (p<0.03), presence of SPINK1 mutation (p=0.01), longer follow-up (p<0.001) were associated with progression to CP.

CONCLUSIONS

Biliopancreatic structural/obstructive causes should always be looked for. It seems ARP is a precursor of CP and progression is associated with idiopathic etiology and presence of genetic mutations. Hence, patients with ARP should be kept on regular follow-up to detect CP.

Association Analysis of PRSS1-PRSS2 and CLDN2-MORC4 Variants in Nonalcoholic Chronic Pancreatitis Using Tropical Calcific Pancreatitis as Model

OBJECTIVE

Association of PRSS1-PRSS2 (rs10273639) and CLDN2-MORC4 (rs12688220 and rs7057398) variants with alcohol-related chronic pancreatitis (CP) is established but with nonalcoholic CP is unclear. We addressed this inconsistency using tropical calcific pancreatitis (TCP) as model.

METHODS

We sequenced 5'-UTR of PRSS1 and genotyped CLDN2-MORC4 variants in 555 patients with TCP and 801 controls and performed association analysis. Gene-gene interaction between PRSS1 and CLDN2-MORC4 variants and with p.Asn34Ser SPINK1 and p.Leu26Val CTSB was also evaluated.

RESULTS

We observed significant association of rs10273639/rs4726576 in PRSS1-PRSS2 (odds ratio [OR] = 0.72; P = 3.50 × 10) and CLDN2-MORC4 variants, rs12688220 (OR = 1.54; P = 1.22 × 10) and rs7057398 (OR = 1.50; P = 1.22 × 10) with TCP. Patients carrying p.Asn34Ser SPINK1 were significantly younger than those with rs4726576 risk genotype (30.0 vs 38.0 years; P = 0.015) and those carrying both were even younger (22.0 years; P = 0.001). Presence of risk allele at rs12688220 in patients carrying p.Asn34Ser SPINK1 delayed the age of onset (32.0 vs 24.0 years; P = 0.013).

CONCLUSIONS

Our study establishes strong association of PRSS1-PRSS2 and CLDN2-MORC4 variants with TCP and thus with nonalcoholic CP. These variants independently interact with p.Asn34Ser SPINK1 and influence the age of onset in TCP. However, latter results need to be replicated in other cohorts.

Genetic predisposition and its impact on natural history of idiopathic acute and acute recurrent pancreatitis in children

BACKGROUND

Genetic predisposition in paediatric idiopathic acute, acute recurrent pancreatitis and its consequences are unknown. We studied frequency of genetic markers in acute, acute recurrent, chronic pancreatitis and their impact on natural history.

METHODS

Over a period of 2 years 68 consecutive children with pancreatitis (35.3% acute, 32.3% acute recurrent, 32.3% chronic) and 25 controls were recruited in a single centre. Common mutations for serine-protease-inhibitor (SPINK1 N34S), protease-inhibitor (PRSS1 R122H) and cystic fibrosis transmembrane conductance regulator (CFTR DeltaF508, 5T) were analysed.

RESULTS

Mean age was 13.4±2.5 years. Overall, 30 cases (SPINK1 N34S n=26, CFTR 5T n=4) and 1 control (SPINK1 N34S) had mutations (p=0.0001). The prevalence of SPINK1 N34S mutation was similar in chronic and acute recurrent pancreatitis (45%). Six children with severe acute pancreatitis had SPINK1 N34S mutations (25%, p<0.05), and 4 were homozygous. On follow-up 5 acute pancreatitis patients with mutations and 1 without mutations developed chronic pancreatitis (p=0.004); 8 cases of acute recurrent pancreatitis progressed to chronic pancreatitis (38%); of these 66.7% had mutations vs. 16.7% who did not (p=0.03).

CONCLUSIONS

Almost 50% of idiopathic chronic, acute recurrent and 33% of acute pancreatitis in children are genetically predisposed. Presence of genetic mutations in acute and recurrent acute pancreatitis increases the risk of developing chronic pancreatitis.

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.

Frequency of CFTR, SPINK1, and cathepsin B gene mutation in North Indian population: connections between genetics and clinical data

Objectives. Genetic mutations and polymorphisms have been correlated with chronic pancreatitis (CP). This study aims to investigate the association of genetic variants of cystic fibrosis transmembrane conductance regulator (CFTR) and serine protease inhibitor Kazal type 1 (SPINK-1) genes and Cathepsin B gene polymorphisms with CP and to associate genetic backgrounds with clinical phenotypes. Methods. 150 CP patients and 150 normal controls were enrolled consecutively. We analyzed SPINK-1 N34S and IVS3+2T>C gene mutations by PCR-restriction-fragment length polymorphism (RFLP). The identification of DF508, G551D, G542X, R117H, and W1282X mutations was carried out by ARMS-PCR. S549N mutation, IVS8 polyTn polymorphism, and Cathepsin B Lec26Val were analysed by PCR-RFLP, nested PCR, and PCR-RFLP plus sequencing, respectively. Results. We found a significant association of SPINK1 (N34S) gene polymorphism. IVS1−37T>C polymorphism shows linkage with 101A>G. 300 chromosomes belonging to the CFTR subgroup exhibited minor allele frequency of 0.04, 0.03, 0.03, 0.013, 0.006, and 0.02 for DF508, G452X, G551D, S549N, R117H, and IVS8 T5, respectively. Except for R117H and IVS8 T5 polymorphisms, all other mutations showed significant variation. Conclusion. Analysis of potential susceptibility variants is needed to support nature of the genes and environment in pancreatitis. This data may help establish genetic screening and prenatal setup for Indian population.

Parathyroid scintigraphy, histopathology correlation in patients with tropical pancreatitis and coexisting primary hyperparathyroidism

Purpose:

Tropical pancreatitis (TP) is a juvenile, non-alcoholic type of chronic pancreatitis and is highly prevalent in Kerala, India. Increasing prevalence of TP and its varied manifestations prompted us to undertake this retrospective analysis. We attempted to study the incidence of TP in patients with primary hyperparathyroidism (PHPT) and correlate with calcium levels, scintigraphy and histopathology findings.

Materials and Methods:

Records of 44 hypercalcemic patients with raised parathormone (PTH) were analyzed. Clinical, biochemical and imaging findings were noted to look for diabetes mellitus and pancreatitis. All patients underwent dual phase ^99m Technetium methoxy isobutyl isonitrile parathyroid scintigraphy in our department between January 2007 and 2010. Gamma probe assisted minimally invasive parathyroidectomy was performed. Histopathological correlation was obtained in all patients.

Results:

Our study shows 18% (8/44 patients) incidence of TP in patients with PHPT (compared to 7% reported in 1970's) in Kerala. Results show involvement of middle aged, non-alcoholic males. No direct association between severity of diabetes, pancreatitis and PHPT was noted in our series. Parathyroid adenoma was the most common underlying pathology. All TP patients’ clinical outcome improved post parathyroidectomy. TP patients with PHPT demonstrated adenomas, mainly composed of oxyphilic cells. Non pancreatitis group interestingly showed a varied picture of adenoma, hyperplasia with predominance of chief cells histologically.

Conclusion:

There is a 2.6 fold increase in the incidence of TP (18%) in patients with PHPT. Hypercalcemia may be the causative factor leading to TP in PHPT patients in our limited series. The data suggests a causal association between pancreatitis and PHPT. Patients presenting with either one or a combination of hypercalcemia, pancreatic dysfunction or raised PTH need to be thoroughly evaluated as their management is interlinked.

Recommendations for the classification of diseases as CFTR-related disorders

Several diseases have been clinically or genetically related to cystic fibrosis (CF), but a consensus definition is lacking. Here, we present a proposal for consensus guidelines on cystic fibrosis transmembrane conductance regulator (CFTR)-related disorders (CFTR-RDs), reached after expert discussion and two dedicated workshops. A CFTR-RD may be defined as "a clinical entity associated with CFTR dysfunction that does not fulfil diagnostic criteria for CF". The utility of sweat testing, mutation analysis, nasal potential difference, and/or intestinal current measurement for the differential diagnosis of CF and CFTR-RD is discussed. Algorithms which use genetic and functional diagnostic tests to distinguish CF and CFTR-RDs are presented. According to present knowledge, congenital bilateral absence of vas deferens (CBAVD), acute recurrent or chronic pancreatitis and disseminated bronchiectasis, all with CFTR dysfunction, are CFTR-RDs.

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.

Genotype-phenotype correlation in 9 patients with tropical pancreatitis and identified gene mutations

The etiopathogenesis of tropical chronic pancreatitis (TCP) remains unclear. Malnutrition, dietary toxins like cyanogens in cassava and micronutrient deficiency are proposed factors. The description and characterization of genetic factors in TCP has added a new dimension to the understanding of pathogenesis of the disease. However, there is sparse data on the association of TCP with cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations. We report 8 patients of TCP with CFTR gene mutations, including one with a novel mutation, and describe the clinical profile of these patients. Further prospective genetic studies on the association of CFTR gene mutations are essential in order to unravel the genetic basis of TCP.

Etiology of chronic pancreatitis: Has it changed in the last decade?

The evidence from recent surveys on chronic pancreatitis carried out around the world shows that alcohol remains the main factor associated with chronic pancreatitis, even if at a frequency lower than that reported previously. It has further confirmed that heavy alcohol consumption and smoking are independent risk factors for chronic pancreatitis. Autoimmune pancreatitis accounts for 2%-4% of all forms of chronic pancreatitis, but this frequency will probably increase over the next few years. The rise in idiopathic chronic pancreatitis, especially in India, represents a black hole in recently published surveys. Despite the progress made so far regarding the possibility of establishing the hereditary forms of chronic pancreatitis and the recognition of autoimmune pancreatitis, it is possible that we are more inaccurate today than in the past in identifying the factors associated with chronic pancreatitis in our patients.

A clinical and radiologic review of uncommon types and causes of pancreatitis

Acute pancreatitis is one of the most common conditions for which emergent imaging is indicated. Alcohol consumption and cholelithiasis are the most common causes of acute pancreatitis in adults, whereas the majority of cases in children are idiopathic or secondary to trauma. A wide variety of structural and biochemical abnormalities may also cause pancreatitis. Although in some cases it is difficult to identify the specific cause of the disease radiologically, certain uncommon types of acute or chronic pancreatitis may have unique imaging features that can help the radiologist make an accurate diagnosis. These unusual types include autoimmune pancreatitis, groove pancreatitis, tropical pancreatitis, hereditary pancreatitis, and pancreatitis in ectopic or heterotopic pancreatic tissue. Pancreatitis may occasionally be seen in association with cystic fibrosis or pancreas divisum, or secondary to worm infestation of the pancreaticobiliary tree (eg, by Ascaris lumbricoides). In addition, primary pancreatic and duodenal masses may occasionally manifest as acute or recurrent acute pancreatitis. Knowledge of the classic imaging findings of these entities allows prompt recognition of the relevant pathologic condition, thereby preventing misdiagnosis and subsequent inappropriate or delayed management.

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.

Genetic aspects of tropical calcific pancreatitis

Tropical calcific pancreatitis (TCP) is a subtype of chronic pancreatitis which is unique to tropical regions. Patients present at young age with recurrent abdominal pain, nutritional deficiencies, and insulin-requiring diabetes. For a long time, the aetiology of this disorder was poorly understood. Several environmental factors, such as malnutrition or the consumption of toxic food components such as cyanogenic glycosides, were proposed as pathogenic factors. In the last decade, a major impact on the understanding of the aetiology of TCP has come from genetic studies on hereditary and idiopathic chronic pancreatitis. Genetic alterations in at least five genetic loci are clearly associated with chronic pancreatitis in the Western world. These include alterations in genes coding for trypsinogens, the most abundant digestive enzymes (PRSS1 and PRSS2), the trypsin inhibitor (SPINK1) and the trypsin-degrading enzyme, chymotrypsinogen C (CTRC). In addition, alterations in the cystic fibrosis (CFTR) gene are associated with idiopathic pancreatitis. TCP clinically resembles non-alcoholic chronic pancreatitis of Western countries, suggesting that similar genetic defects might also be of importance in this disease entity. Indeed, alterations in at least two genes, SPINK1 and CTRC, are strongly associated with TCP. The current review focuses on the recent developments in the understanding of the genetic basis of inherited pancreatitis, with special emphasis on TCP.

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

BACKGROUND

Tropical calcific pancreatitis (TCP) is a type of chronic pancreatitis unique to developing countries in tropical regions and one of its important features is invariable progression to diabetes, a condition called fibro-calculous pancreatic diabetes (FCPD), but the nature of diabetes in TCP is controversial. We analysed the recently reported type 2 diabetes (T2D) associated polymorphisms in the TCF7L2 gene using a case-control approach, under the hypothesis that TCF7L2 variants should show similar association if diabetes in FCPD is similar to T2D. We also investigated the interaction between the TCF7L2 variants and N34S SPINK1 and L26V CTSB mutations, since they are strong predictors of risk for TCP.

METHODS

Two polymorphisms rs7903146 and rs12255372 in the TCF7L2 gene were analyzed by direct sequencing in 478 well-characterized TCP patients and 661 healthy controls of Dravidian and Indo-European ethnicities. Their association with TCP with diabetes (FCPD) and without diabetes was tested in both populations independently using chi-square test. Finally, a meta analysis was performed on all the cases and controls for assessing the overall significance irrespective of ethnicity. We dichotomized the whole cohort based on the presence or absence of N34S SPINK1 and L26V CTSB mutations and further subdivided them into TCP and FCPD patients and compared the distribution of TCF7L2 variants between them.

RESULTS

The allelic and genotypic frequencies for both TCF7L2 polymorphisms, did not differ significantly between TCP patients and controls belonging to either of the ethnic groups or taken together. No statistically significant association of the SNPs was observed with TCP or FCPD or between carriers and non-carriers of N34S SPINK1 and L26V CTSB mutations. The minor allele frequency for rs7903146 was different between TCP and FCPD patients carrying the N34S SPINK1 variant but did not reach statistical significance (OR = 1.59, 95% CI = 0.93-2.70, P = 0.09), while, TCF7L2variant showed a statistically significant association between TCP and FCPD patients carrying the 26V allele (OR = 1.69, 95% CI = 1.11-2.56, P = 0.013).

CONCLUSION

Type 2 diabetes associated TCF7L2 variants are not associated with diabetes in TCP. Since, TCF7L2 is a major susceptibility gene for T2D, it may be hypothesized that the diabetes in TCP patients may not be similar to T2D. Our data also suggests that co-existence of TCF7L2 variants and the SPINK1 and CTSB mutations, that predict susceptibility to exocrine damage, may interact to determine the onset of diabetes in TCP patients.

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.

Tropical chronic pancreatitis: an update

Tropical chronic pancreatitis represents a juvenile nonalcoholic form of chronic pancreatitis prevalent in many tropical developing countries. Tropical chronic pancreatitis differs from temperate zone pancreatitis in its younger age of onset, more accelerated course, higher prevalence of pancreatic calculi and diabetes, and greater propensity to pancreatic malignancy. The diabetic stage of the disease is referred to as fibrocalculous pancreatic diabetes. The diabetes is severe and insulin requiring although ketosis resistant. Diabetic complications occur in fibrocalculous pancreatic diabetes just like in other primary forms of diabetes. The etiology of tropical chronic pancreatitis remains unclear, although malnutrition along with dietary cyanogen toxicity, antioxidant deficiency, and a genetic predisposition have been proposed. In the last few decades, the prognosis has markedly improved as a result of better management of diabetes. Yet a better understanding of the pathogenesis of tropical chronic pancreatitis could further improve treatment options and offer an opportunity for prevention of this disorder, which leads to severe morbidity in a large proportion of affected patients.

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/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.

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.

Molecular diagnosis of cystic fibrosis

A review of the current molecular diagnosis of cystic fibrosis including an introduction to cystic fibrosis, the gene function, the phenotypic variation, who should be screened for which mutation, newborn and couple screening, quality assurance, phenotype-genotype correlation, methods and method limitations, options, statements, recommendations, useful Websites and treatments.

[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.