Different CFTR mutational spectrum in alcoholic and idiopathic chronic pancreatitis?

Molecular diagnosis of cystic fibrosis by RNA obtained from nasal epithelial cells

BACKGROUND

The diagnosis of cystic fibrosis (CF) is established when characteristic clinical signs are coupled with biallelic CFTR pathogenic variants. No previously reported non-canonical splice site variants have to be considered as variants of uncertain significance unless their effect on splicing has been validated.

METHODS

Two variants identified by next-generation sequencing were evaluated. We assayed their effects on splicing employing RNA analysis and real-time expression quantification from RNA obtained from the nasal epithelial cells of a patient with clinically suspected CF and of two patients with milder phenotypes (CFTR-related disorders).

RESULTS

The variant c.164+2dup causes skipping of exon 2 (p.(Ser18_Glu54del)) and exon 2 plus 3 (p.(Ser18Argfs*16)) in CFTR mRNA. Exon 2 expression in the patient heterozygous for c.164+2dup was decreased to 7 % of the exon 2 expression in the controls. The synonymous variant c.1584G>A causes a partial skipping of exon 11. The exon 11 expression in the two patients heterozygous for this variant was 22 % and 42 % of that of the controls, respectively.

CONCLUSION

We conclude that variant c.164+2dup affects mRNA processing and can be considered a CF-causing variant. The results of the functional assay also showed that the p.(Glu528=) variant, usually categorized as a neutral variant based on epidemiological data, partially affects mRNA processing in our patients. This finding would allow us to reclassify the variant as a CFTR-related variant with incomplete penetrance. RNA obtained from nasal epithelial cells is an easy and accurate tool for CFTR functional studies in patients with unclassified splice variants.

The Effect of Synonymous Single-Nucleotide Polymorphisms on an Atypical Cystic Fibrosis Clinical Presentation

Synonymous single nucleotide polymorphisms (sSNPs), which change a nucleotide, but not the encoded amino acid, are perceived as neutral to protein function and thus, classified as benign. We report a patient who was diagnosed with cystic fibrosis (CF) at an advanced age and presented very mild CF symptoms. The sequencing of the whole cystic fibrosis transmembrane conductance regulator (CFTR) gene locus revealed that the patient lacks known CF-causing mutations. We found a homozygous sSNP (c.1584G>A) at the end of exon 11 in the CFTR gene. Using sensitive molecular methods, we report that the c.1584G>A sSNP causes cognate exon skipping and retention of a sequence from the downstream intron, both of which, however, occur at a relatively low frequency. In addition, we found two other sSNPs (c.2562T>G (p.Thr854=) and c.4389G>A (p.Gln1463=)), for which the patient is also homozygous. These two sSNPs stabilize the CFTR protein expression, compensating, at least in part, for the c.1584G>A-triggered inefficient splicing. Our data highlight the importance of considering sSNPs when assessing the effect(s) of complex CFTR alleles. sSNPs may epistatically modulate mRNA and protein expression levels and consequently influence disease phenotype and progression.

A single-centre prospective, cohort study of the natural history of acute pancreatitis

BACKGROUND

The natural history of acute pancreatitis is based on clinical studies that aim to elucidate the course of disease on the basis of predicted risk factors.

AIMS

To evaluate the long-term occurrence of recurrent acute pancreatitis and chronic pancreatitis in a cohort of patients following an initial episode of acute pancreatitis.

METHODS

196 patients were enrolled consecutively and studied prospectively. Clinical characteristics, exogenously/endogenously-associated factors, and evolution to recurrent acute pancreatitis and chronic pancreatitis were analyzed.

RESULTS

40 patients developed recurrent acute pancreatitis 13 of whom developed chronic pancreatitis. In a univariate analysis, recurrent acute pancreatitis was associated with an idiopathic aetiology (p<0.001), pancreas divisum (p=0.001), and higher usage of cigarettes and alcohol (p<0.001; p=0.023). Chronic pancreatitis was associated with a severe first episode of acute pancreatitis (p=0.048), PD (p=0.03), and cigarette smoking (p=0.038). By multivariate analysis, pancreas divisum was an independent risk factor for recurrent acute pancreatitis (OR 11.5, 95% CI 1.6-83.3). A severe first-episode of acute pancreatitis increased the risk of progressing to chronic pancreatitis by nine-fold.

CONCLUSIONS

Special attention should be given to patients who experience a severe first attack of acute pancreatitis as there appears to be an increased risk of developing chronic pancreatitis over the long term.

Mechanisms of CFTR functional variants that impair regulated bicarbonate permeation and increase risk for pancreatitis but not for cystic fibrosis

CFTR is a dynamically regulated anion channel. Intracellular WNK1-SPAK activation causes CFTR to change permeability and conductance characteristics from a chloride-preferring to bicarbonate-preferring channel through unknown mechanisms. Two severe CFTR mutations (CFTRsev) cause complete loss of CFTR function and result in cystic fibrosis (CF), a severe genetic disorder affecting sweat glands, nasal sinuses, lungs, pancreas, liver, intestines, and male reproductive system. We hypothesize that those CFTR mutations that disrupt the WNK1-SPAK activation mechanisms cause a selective, bicarbonate defect in channel function (CFTRBD) affecting organs that utilize CFTR for bicarbonate secretion (e.g. the pancreas, nasal sinus, vas deferens) but do not cause typical CF. To understand the structural and functional requirements of the CFTR bicarbonate-preferring channel, we (a) screened 984 well-phenotyped pancreatitis cases for candidate CFTRBD mutations from among 81 previously described CFTR variants; (b) conducted electrophysiology studies on clones of variants found in pancreatitis but not CF; (c) computationally constructed a new, complete structural model of CFTR for molecular dynamics simulation of wild-type and mutant variants; and (d) tested the newly defined CFTRBD variants for disease in non-pancreas organs utilizing CFTR for bicarbonate secretion. Nine variants (CFTR R74Q, R75Q, R117H, R170H, L967S, L997F, D1152H, S1235R, and D1270N) not associated with typical CF were associated with pancreatitis (OR 1.5, p = 0.002). Clones expressed in HEK 293T cells had normal chloride but not bicarbonate permeability and conductance with WNK1-SPAK activation. Molecular dynamics simulations suggest physical restriction of the CFTR channel and altered dynamic channel regulation. Comparing pancreatitis patients and controls, CFTRBD increased risk for rhinosinusitis (OR 2.3, p<0.005) and male infertility (OR 395, p<<0.0001). WNK1-SPAK pathway-activated increases in CFTR bicarbonate permeability are altered by CFTRBD variants through multiple mechanisms. CFTRBD variants are associated with clinically significant disorders of the pancreas, sinuses, and male reproductive system.

Next generation diagnostics of cystic fibrosis and CFTR-related disorders by targeted multiplex high-coverage resequencing of CFTR

BACKGROUND

Here we have developed a novel and much more efficient strategy for the complete molecular characterisation of the cystic fibrosis (CF) transmembrane regulator (CFTR) gene, based on multiplexed targeted resequencing. We have tested this approach in a cohort of 92 samples with previously characterised CFTR mutations and polymorphisms.

METHODS

After enrichment of the pooled barcoded DNA libraries with a custom NimbleGen SeqCap EZ Choice array (Roche) and sequencing with a HiSeq2000 (Illumina) sequencer, we applied several bioinformatics tools to call mutations and polymorphisms in CFTR.

RESULTS

The combination of several bioinformatics tools allowed us to detect all known pathogenic variants (point mutations, short insertions/deletions, and large genomic rearrangements) and polymorphisms (including the poly-T and poly-thymidine-guanine polymorphic tracts) in the 92 samples. In addition, we report the precise characterisation of the breakpoints of seven genomic rearrangements in CFTR, including those of a novel deletion of exon 22 and a complex 85 kb inversion which includes two large deletions affecting exons 4-8 and 12-21, respectively.

CONCLUSIONS

This work is a proof-of-principle that targeted resequencing is an accurate and cost-effective approach for the genetic testing of CF and CFTR-related disorders (ie, male infertility) amenable to the routine clinical practice, and ready to substitute classical molecular methods in medical genetics.

The Spanish Pancreatic Club recommendations for the diagnosis and treatment of chronic pancreatitis: part 1 (diagnosis)

Chronic pancreatitis (CP) is a relatively uncommon, complex and heterogeneous disease. The absence of a gold standard applicable to the initial phases of CP makes its early diagnosis difficult. Some of its complications, particularly chronic pain, can be difficult to manage. There is much variability in the diagnosis and treatment of CP and its complications amongst centers and professionals. The Spanish Pancreatic Club has developed a consensus on the management of CP. Two coordinators chose a multidisciplinary panel of 24 experts on this disease. A list of questions was drafted, and two experts reviewed each question. Then, a draft was produced and shared with the entire panel of experts and discussed in a face-to-face meeting. This first part of the consensus addresses the diagnosis of CP and its complications.

A novel exon duplication of the cystic fibrosis transmembrane conductance regulator in a patient presenting with adult-onset recurrent pancreatitis

Pancreatitis is a rare occurrence in patients with cystic fibrosis (CF) affecting 1.2% of all patients, but it can be the first presenting sign in approximately 15% of adults with pancreatic sufficiency and a milder CF phenotype. We report a case of a woman with recurrent pancreatitis who has one cystic fibrosis-causing mutation (G551D) and the first known description of a pathologic duplication of exon 19 of the CF transmembrane conductance regulator (CFTR). A 30-year-old white woman with 30 attacks of pancreatitis over a 5-year period starting at age 25 presented to the genetics department. She was found to have a mutation in the SPINK1 gene, IVS3+184T>A, and one cystic fibrosis-causing mutation (G551D) prompting full gene sequencing of the CFTR, revealing an additional duplication of exon 19. Sweat chloride testing was elevated at 97 and 106 mmol/L. Despite normal growth parameters and lung function, it is important to be aware of recurrent pancreatitis as a presenting sign of CF. Comprehensive CF gene analysis is necessary to detect a second CF-causing mutation that may put patients at risk for more severe symptoms of pancreatitis. There is a significant difference in the prevalence of heterozygote mutations between available testing methods.

Genetic risk for alcoholic chronic pancreatitis

In recent years many studies have examined the genetic predisposition to pancreatic diseases. Pancreatic disease of an alcoholic etiology was determined to be a multi-factorial disease, where environmental factors interact with the genetic profile of the individual. In this review we discuss the main results from studies examining the frequency of genetic mutations in alcoholic chronic pancreatitis.

Common CFTR haplotypes and susceptibility to chronic pancreatitis and congenital bilateral absence of the vas deferens

CFTR mutations enhance susceptibility for idiopathic chronic pancreatitis (ICP) and congenital bilateral absence of the vas deferens (CBAVD); however, it is unknown why CFTR heterozygotes are at increased disease risk. We recently showed that common CFTR variants are associated with aberrantly spliced transcripts. Here, we genotyped for common CFTR variants and tested for associations in two ICP (ICP-A: 126 patients, 319 controls; ICP-B: 666 patients, 1,181 controls) and a CBAVD population (305 patients, 319 controls). Haplotype H10 (TG11-T7-470V) conferred protection (ICP-A: OR 0.19, P<0.0001; ICP-B: OR 0.78, P = 0.06; CBAVD OR 0.08, P<0.001), whereas haplotype H3 (TG10-T7-470M) increased disease risk (ICP-A: OR 8.34, P = 0.003; ICP-B: OR 1.88, P = 0.007; CBAVD: OR 5.67, P = 0.01). The risk of heterozygous CFTR mutations carriers for ICP (OR 2.44, P<0.001) and CBAVD (OR 14.73, P<0.001) was fully abrogated by the H10/H10 genotype. Similarly, ICP risk of heterozygous p.Asn34Ser SPINK1 mutation carriers (OR 10.34, P<0.001) was compensated by H10/H10. Thus, common CFTR haplotypes modulate ICP and CBAVD susceptibility alone and in heterozygous CFTR and p.Asn34Ser mutation carriers. Determination of these haplotypes helps to stratify carriers into high- and low-risk subjects, providing helpful information for genetic counseling.

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

BACKGROUND AND AIMS

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

RESULTS

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

CONCLUSIONS

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

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.

Independent contribution of common CFTR variants to chronic pancreatitis

OBJECTIVE

We have assessed whether CFTR gene has a major impact on chronic pancreatitis (CP) pathogenesis than that provided by the CFTR mutations. For this aim, we have evaluated clinical parameters, CFTR mutations, and 3 potential regulatory CFTR variants (coding single-nucleotide polymorphisms): c.1540A>G, c.2694T>G, and c.4521G>A.

METHODS

CFTR gene analysis was performed in a cohort of 136 CP patients and 93 controls from Spanish population using current scanning techniques (single-strand conformation polymorphism/heteroduplex, denaturing gradient gel electrophoresis, and denaturing high-performance liquid chromatography) and direct sequencing.

RESULTS

A higher frequency of CFTR mutations were observed in patients (39%) than in controls (15%; P < or = 0.001), differences being mostly attributable to the prevalence of the cystic fibrosis (CF)-causing mutations (P = 0.009). The analysis of variants has shown statistically significant differences between patients and controls for c.4521G>A (Pcorrected = 0.036). Furthermore, the multi-marker analysis revealed that the 1540A;2694G;4521A (AGA) haplotype was more prevalent in CP than controls (Pcorrected = 0.042). Remarkably, this association was unrelated to CF-causing mutations (P = 0.006).

CONCLUSIONS

Our results corroborate the higher susceptibility of CF carriers to CP and, furthermore, suggest that the AGA haplotype could contribute to an increased risk in the development of CP irrespective of other CF-causing mutations.

CFTR polymorphisms in patients with alcoholic chronic pancreatitis

INTRODUCTION

Pancreas susceptibility to alcohol is variable and only 5-10% of chronic alcohol abusers develop chronic pancreatitis; the role of genetic factors in this process is unknown. The CFTR gene encodes a protein that acts on epithelial cells and plays a key role in normal exocrine pancreatic function.

METHODS

This study investigated the frequency of polymorphisms in intron 8 of the CFTR gene in patients with alcoholic chronic pancreatitis. Three groups of patients were studied: group A - 68 adult alcoholics with a diagnosis of chronic pancreatitis; group B - 68 adult alcoholics without pancreatic disease or liver cirrhosis and group C - 104 healthy nonalcoholic adults.

RESULTS

T5/T7 genotype was more frequent in group A (11.8%) than in group B (2.9%) (p = 0.0481), and there was no statistical difference when groups A and C (5.8%) were compared (p = 0.1317). The haplotype combination (TG)10-T7/(TG)11-T7 was more frequent in groups B (23.5%) and C (20.2%) than in group A (7.3%) (p = 0.0080 and 0.0162).

CONCLUSION

There are differences when these three groups are compared and individuals with T5/T7 genotype might have a greater risk of developing chronic pancreatitis when they become chronic alcoholics.

Clinical and radiological outcome of patients suffering from chronic pancreatitis associated with gene mutations

OBJECTIVES

Cystic fibrosis transmembrane conductance regulator (CFTR), cationic trypsinogen gene (PRSS1), and serine protease inhibitor kazal type 1 (SPINK1) gene mutations have been associated with chronic pancreatitis (CP). The aim of this study was to compare clinical and radiological findings in sporadic CP with (CPgm) and without (CPwt) gene mutations.

METHODS

Data from patients observed between 2001 and 2006 were collected. All patients were tested for 25 CFTR gene mutations, for R122H and N29I on the PRSS1 gene, and for N34S mutation on the SPINK1 gene.

RESULTS

We found 34 (17.2%) of 198 patients with CPgm, 23 (11.6%) of them on the CFTR gene, 11 (5.6%) on the SPINK1, and none on the PRSS1 gene. The age at clinical onset was younger in CPgm (36.2 +/- 17.2 years) than in CPwt (44 +/- 12.6 years; P = 0.005). There were more heavy drinkers among CPwt (33%) than among CPgm (9%; P = 0.003), and the same applied to smokers (69% vs 33%, respectively; P < 0.0001). In CPgm group, the onset of pancreatic calcifications was observed more frequently in drinkers and/or smokers. Exocrine and endocrine insufficiency occurred less frequently and later in CPgm than in CPwt patients.

CONCLUSIONS

Clinical and radiological outcome differ in CPgm compared with CPwt. Alcohol, even in small quantities, and cigarette smoking influence the onset of pancreatic calcifications.

N-terminal CFTR missense variants severely affect the behavior of the CFTR chloride channel

Over 1,500 cystic fibrosis transmembrane conductance regulator (CFTR) gene sequence variations have been identified in patients with cystic fibrosis (CF) and related disorders involving an impaired function of the CFTR chloride channel. However, detailed structure-function analyses have only been established for a few of them. This study aimed evaluating the impact of eight N-terminus CFTR natural missense changes on channel behavior. By site-directed mutagenesis, we generated four CFTR variants in the N-terminal cytoplasmic tail (p.P5L, p.S50P, p.E60K, and p.R75Q) and four in the first transmembrane segment of membrane-spanning domain 1 (p.G85E/V, p.Y89C, and p.E92K). Immunoblot analysis revealed that p.S50P, p.E60K, p.G85E/V, and p.E92K produced only core-glycosylated proteins. Immunofluorescence and whole cell patch-clamp confirmed intracellular retention, thus reflecting a defect of CFTR folding and/or trafficking. In contrast, both p.R75Q and p.Y89C had a glycosylation pattern and a subcellular distribution comparable to the wild-type CFTR, while the percentage of mature p.P5L was considerably reduced, suggesting a major biogenesis flaw on this channel. Nevertheless, whole-cell chloride currents were recorded for all three variants. Single-channel patch-clamp analyses revealed that the channel activity of p.R75Q appeared similar to that of the wild-type CFTR, while both p.P5L and p.Y89C channels displayed abnormal gating. Overall, our results predict a major impact of the CFTR missense variants analyzed, except p.R75Q, on the CF phenotype and highlight the importance of the CFTR N-terminus on channel physiology.

Spectrum of mutations and variants/haplotypes of CFTR and genotype-phenotype correlation in idiopathic chronic pancreatitis and controls in Chinese by complete analysis

Mutations in cystic fibrosis transmembrane conductance regulator (CFTR) gene have been reported in patients with chronic pancreatitis. The authors examine whether the mutations and haplotypes of CFTR will increase the risk of developing idiopathic chronic pancreatitis (ICP) in Chinese and their genotype and phenotype correlations. Seventy-eight patients with ICP and 200 geographically and ethnically matched controls in Taiwan were analyzed. The entire 27 coding and intronic regions of the CFTR gene were identified using heteroduplex analytical techniques and confirmed by sequencing analysis. The presence of 125G/C, 1001+10C>T, IVSTn(TG)m, 1540A>G, c2694T>G, and c4521G>A were determined by directing sequencing. Abnormal CFTR allele was found to be thrice as frequent in ICP patients as in controls (22/156 vs 19/400, p < 0.0001). T5 allele was associated with early onset of ICP. In six-loci haplotype analysis, 13 common haplotypes were assembled in the 278 individuals tested. The 125G/1001+11C/TG12/470M/2694T/4521G haplotype was associated with risk of ICP (odds ratio 11.3; 95% confidence interval 2.3-54.6, p = 0.008) in Chinese. The mutation spectrum is different from other ethnic groups. A population-specific panel of CFTR changes should be recommended for targeted populations including ICP in Chinese. It is important to design suitable screening programs for different populations.

Contribution of the CFTR gene, the pancreatic secretory trypsin inhibitor gene (SPINK1) and the cationic trypsinogen gene (PRSS1) to the etiology of recurrent pancreatitis

Acute recurrent/chronic pancreatitis (CP) is a complex multigenic disease. This is a case-control study consisting of 25 Greek patients with CP and a control population of 236 healthy Greek subjects. The whole coding area and neighboring intronic regions of the three genes were screened. Seventeen of 25 patients (68%) had mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene: nine compound heterozygotes with either mild or severe mutations and eight heterozygotes. Four patients (16%) carried CFTR-modulating haplotypes V470-TG11-T5 and V470-TG12-T7. All were negative for PRSS1 gene mutations, while variants c.486C/T and c.738C/T were found in nine patients each, three homozygotes for the minor alleles. Two carried SPINK1 gene mutation p.N34S, one being transheterozygote with CFTR mutation p.F1052V. The promoter variant -253T>C was found in four individuals (one homozygous for the minor allele), all four being transheterozygotes with mutations in the CFTR gene as well. Finally two carried c.272C/T in the 3' untranslated region, one being a p.N34S carrier as well. In total, 80% (20/25) of patients had a molecular defect in one or both of the CFTR and SPINK1 genes, suggesting that mutations/variants in the CFTR plus or minus mutations in the SPINK1, but not the PRSS1 gene, may confer a high risk for recurrent pancreatitis.

Spectrum of mutations in the CFTR gene in cystic fibrosis patients of Spanish ancestry

We analyzed 1,954 Spanish cystic fibrosis (CF) alleles in order to define the molecular spectrum of mutations in the CFTR gene in Spanish CF patients. Commercial panels showed a limited detection power, leading to the identification of only 76% of alleles. Two scanning techniques, denaturing gradient gel electrophoresis (DGGE) and single strand conformation polymorphism/hetroduplex (SSCP/HD), were carried out to detect CFTR sequence changes. In addition, intragenic markers IVS8CA, IVS8-6(T)n and IVS17bTA were also analyzed. Twelve mutations showed frequencies above 1%, p.F508del being the most frequent mutation (51%). We found that eighteen mutations need to be studied to achieve a detection level of 80%. Fifty-one mutations (42%) were observed once. In total, 121 disease-causing mutations were identified, accounting for 96% (1,877 out of 1,954) of CF alleles. Specific geographic distributions for the most common mutations, p.F508del, p.G542X, c.1811 + 1.6kbA > G and c.1609delCA, were confirmed. Furthermore, two other relatively common mutations (p.V232D and c.2789 + 5G > A) showed uneven geographic distributions. This updated information on the spectrum of CF mutations in Spain will be useful for improving genetic testing, as well as to facilitate counselling in people of Spanish ancestry. In addition, this study contributes to defining the molecular spectrum of CF in Europe, and corroborates the high molecular mutation heterogeneity of Mediterranean populations.

A large deletion in the CFTR gene in CBAVD

PURPOSE

Most cystic fibrosis mutation screening methods do not detect large exon deletions or duplications in the cystic fibrosis transmembrane regulator gene. We looked for such mutations in congenital bilateral absence of the vas deferens patients in whom routine screening assays had identified only one or no cystic fibrosis transmembrane regulator gene mutations.

METHODS

DNA samples from 48 men with congenital bilateral absence of the vas deferens were tested for exonic deletions and duplications in the cystic fibrosis transmembrane regulator gene using a laboratory-developed semiquantitative fluorescent PCR assay.

RESULTS

Semi-quantitative fluorescent PCR identified a large deletion in one (2%) of the 48 patients. This patient, previously characterized as carrying only the IVS8-5T mutation, was found to have a deletion of exons 22-24 of the cystic fibrosis transmembrane regulator gene. In a second patient with the IVS8-5T mutation, we identified a one-base pair insertion in exon 17b that disrupted the reading frame.

CONCLUSIONS

Analysis of the cystic fibrosis transmembrane regulator gene for exon deletions and duplications should be included for complete study of CBAVD patients, especially those considering assisted reproduction.

ERCP findings in idiopathic pancreatitis: patients who are cystic fibrosis gene positive and negative

BACKGROUND

Our series of patients with idiopathic pancreatitis (IP) found a cystic fibrosis (CF) gene abnormality in 19% compared with 3.5% in patients without pancreatitis.

OBJECTIVE

The objective was to determine whether the CF gene predicts more severe ERP findings.

DESIGN

This was a retrospective case-control study.

SETTING AND PATIENTS

From July 1998 to August 2004, CF gene analysis was performed in 819 patients with IP via Genzyme Genetics. The panel tests for 70 to 87 alleles and has a detection rate of more than 90% of the cases. Sixty-nine patients (8.4%) who had at least one CF gene positive mutation were the study cohort. A total of 218 patients with IP and negative CF gene mutation were randomly selected from our database to be in the control group.

MAIN OUTCOME MEASUREMENTS

Pancreatograms were evaluated for chronic pancreatitis (CP) based on Cambridge criteria. The results of the gene analysis were not available at the time of pancreatogram interpretation.

RESULTS

Among patients positive for the CF gene, 42 (61%) were women. The mean age at intervention was 40 years (range 14-80 years), and 48 patients (70%) had cholecystectomy. Among patients who were negative for the CF gene, 147 (67%) were women. The mean age at intervention was 41 years (range 9-89 years), and 125 patients (57%) had cholecystectomy. Compared with controls, cases had higher incidence of CP (62% vs. 48%, p = 0.05), grade III CP (35% vs. 18%, p = 0.004), pseudocysts (12% vs. 4%, p = 0.036) and pancreatic strictures (20% vs. 8%, p = 0.008).

LIMITATIONS

The limitations of the study were (1) retrospective design and (2) the panel used tests only for 70 to 87 alleles (of approximately, 900 CF transmembrane conductance regulator genes known).

CONCLUSIONS

The mean age at intervention in both groups was similar. CP, grade III CP, pseudocysts, and pancreatic strictures were more common among patients who were CF gene positive.

Mutation analysis of SPINK1 and CFTR gene in Korean patients with alcoholic chronic pancreatitis

Several genetic mutations have been reported to increase susceptibility to chronic pancreatitis. However, their roles in alcoholic chronic pancreatitis are controversial. We investigated the prevalence of SPINK1 N34S and new CFTR Q1352H mutations in alcoholic chronic pancreatitis in Korea. Forty-three patients with alcoholic chronic pancreatitis were enrolled and 35 healthy individuals served as controls. The SPINK1 N34S mutation was detected by the PCR-RFLP technique. The CFTR Q1352H mutation was examined with PCR direct sequencing. Mean age of chronic pancreatitis and control groups was 53.2 and 51.3 years, respectively. A SPINK1 N34S was detected as a heterozygote in one (2.4%) patient with alcoholic chronic pancreatitis and a heterozygote CFTR Q1352H was detected in one other patient. In the control population, neither SPINK1 nor CFTR mutation was detected. This study shows that SPINK1 N34S and CFTR Q1352H mutations are uncommon and do not play an important role in chronic alcoholic pancreatitis in Korea.

The cystic fibrosis transmembrane conductance regulator gene and ion channel function in patients with idiopathic pancreatitis

Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations are associated with cystic fibrosis (CF)-related monosymptomatic conditions, including idiopathic pancreatitis. We evaluated prospectively enrolled patients who had idiopathic recurrent acute pancreatitis or idiopathic chronic pancreatitis, healthy controls, CF heterozygotes, and CF patients (pancreatic insufficient or sufficient) for evidence of CFTR gene mutations and abnormalities of ion transport by sweat chloride and nasal potential difference testing. DNA samples from anonymous blood donors were controls for genotyping. At least one CFTR mutation or variant was carried in 18 of 40 patients (45%) with idiopathic chronic pancreatitis and in 6 of 16 patients (38%) with idiopathic recurrent acute pancreatitis but in only 11 of the 50 controls (22%, P=0.005). Most identified mutations were rare and would not be identified in routine genetic screening. CFTR mutations were identified on both alleles in six patient (11%). Ion transport measurements in patients with pancreatitis showed a wide range of results, from the values in patients with classically diagnosed CF to those in the obligate heterozygotes and healthy controls. In general, ion channel measurements correlated with the number and severity of CFTR mutations. Twelve of 56 patients with pancreatitis (21%) fulfilled current clinical criteria for the diagnosis of CF, but CFTR genotyping alone confirmed the diagnosis in only two of these patients. We concluded that extensive genotyping and ion channel testing are useful to confirm or exclude the diagnosis of CF in the majority of patients with idiopathic pancreatitis.

Chronic pancreatitis

PURPOSE OF REVIEW

As in our previous reviews, we endeavor to review important new observations in chronic pancreatitis made in the past year. We included articles, including review articles, only if they contained new observations or readdressed old questions and provided new insights into old and new concepts.

RECENT FINDINGS

Important observations include the following: (1) Strong association between cystic fibrosis transmembrane regulator dysfunction/mutations and 'recurrent acute pancreatitis', particularly in patients with pancreas divisum (2) Pancreas divisum may be incidental finding in recurrent acute pancreatitis (3) Smoking increases risk of chronic pancreatitis (4) Coxsackie B virus may increase severity of alcoholic chronic pancreatitis (5) CD4+ T cells and an immune reaction against amylase may play a role in pathogenesis of autoimmune pancreatitis (6) 2-(18F)-Fluro-2-deoxy-D-glucose positron emission tomography might be useful to detect pancreatic cancer in chronic pancreatitis patients at risk for developing pancreatic cancer, but contrast-enhanced Doppler ultrasound or endosonography may be as sensitive and better than contrast enhanced computed tomography (7) Superiority of surgery vs endotherapy for long term pain relief and weight gain in painful chronic pancreatitis (8) Early treatment of pain and malabsorption may improve life quality (9) Antifibrogenesis and fibrolytic agents as potential therapies.

SUMMARY

Ongoing basic and clinical research this past year has further characterized genetic, molecular and clinical aspects of chronic pancreatitis. The advent of predictable and lasting treatments of chronic pancreatitis is most likely to appear on the wings of carefully conducted studies targeting genetic and molecular mechanisms of chronic pancreatitis, particularly pancreatic fibrogenesis.