Genetic testing in pancreatitis

Genetic Variation in ABCC4 and CFTR and Acute Pancreatitis during Treatment of Pediatric Acute Lymphoblastic Leukemia

Background: Acute pancreatitis (AP) is a serious, mechanistically not entirely resolved side effect of L-asparaginase-containing treatment for acute lymphoblastic leukemia (ALL). To find new candidate variations for AP, we conducted a genome-wide association study (GWAS). Methods: In all, 1,004,623 single-nucleotide variants (SNVs) were analyzed in 51 pediatric ALL patients with AP (cases) and 1388 patients without AP (controls). Replication used independent patients. Results: The top-ranked SNV (rs4148513) was located within the ABCC4 gene (odds ratio (OR) 84.1; p = 1.04 × 10⁻¹⁴). Independent replication of our 20 top SNVs was not supportive of initial results, partly because rare variants were neither present in cases nor present in controls. However, results of combined analysis (GWAS and replication cohorts) remained significant (e.g., rs4148513; OR = 47.2; p = 7.31 × 10⁻⁹). Subsequently, we sequenced the entire ABCC4 gene and its close relative, the cystic fibrosis associated CFTR gene, a strong AP candidate gene, in 48 cases and 47 controls. Six AP-associated variants in ABCC4 and one variant in CFTR were detected. Replication confirmed the six ABCC4 variants but not the CFTR variant. Conclusions: Genetic variation within the ABCC4 gene was associated with AP during the treatment of ALL. No association of AP with CFTR was observed. Larger international studies are necessary to more conclusively assess the risk of rare clinical phenotypes.

Paediatric pancreatic diseases

Paediatric pancreatic diseases are often under-recognised and may be associated with severe diseases and significant clinical consequences. In recent years, advances have been made in key areas, particularly with the contributions from international societies and study groups focused on paediatric pancreatic disease research. This review focuses on the two key manifestations of pancreatic disorders in childhood, pancreatitis and exocrine pancreatic dysfunction.

History of paediatric gastroenterology in Australia

Paediatric gastroenterology in Australia has undergone remarkable changes over the more than six decades since Charlotte Anderson's pioneering work, and is now a well-established specialty in its own right. Australian paediatric gastroenterologists have made important contributions nationally and internationally.

Chronic Pancreatitis: What the Clinician Wants to Know from MR Imaging

Diagnosis of chronic pancreatitis requires a complete medical history and clinical investigations, including imaging technologies and function tests. MR imaging/magnetic resonance cholangiopancreatography is the preferred diagnostic tool for detection of ductal and parenchymal changes in patients with chronic pancreatitis. Ductal changes may not be present in the initial phase of chronic pancreatitis. Therefore, early diagnosis remains challenging.

Genetic Mutations in Pediatric Pancreatitis

OBJECTIVES

The aim of our study was to describe the prevalence, characteristics, and outcomes of children with acute recurrent (ARP) or chronic (CP) pancreatitis with or without mutations in PRSS1, CFTR or SPINK1.

METHODS

Retrospective chart review of children with ARP or CP with and without testing for PRSS1, CFTR, and SPINK1. Demographics, clinical features, management, and outcome were collected. Analysis of variance was used to compare continuous variables and χ or Fisher exact test for categorical variables.

RESULTS

Ninety-one subjects with ARP (n = 77) or CP (n = 14) were identified and included in this study. Of these, 37 (41%) were male, 44 were white, and 30 were Hispanic. Thirty-three (36%) had at least 1 mutation identified (Pan-Mut): PRSS1 (7), CFTR (21), SPINK1 (3), SPINK/CFTR (2). Thirty-six were tested but had no mutation, and 22 were not tested. The Pan-Mut subjects were more likely to have a family history of pancreatitis but there were no differences in the clinical features, imaging or outcome.

CONCLUSIONS

Mutations in CFTR, SPINK1 or PRSS1 are present in one third of pediatric ARP and CP with no other cause. No clinical features or outcomes differentiated between the Pan-Mut group and the no-mutation group. The Pan-Mut subjects were more likely to have a family history of pancreatitis. Pediatric ARP and CP without identified cause should undergo genetic testing.

Approach to patients with suspected chronic pancreatitis: a comprehensive review

Chronic pancreatitis (CP) represents a significant health care burden in the United States. Diagnosing it early and accurately is important for the efficient management of these patients. However, the early diagnosis of CP, when structural and functional pancreatic changes are subtle, remains difficult. Complicating this is the large cohort of patients with nonspecific abdominal pain who are often suspected of having early CP and who utilize significant health care resources in attempts at diagnosis and management. We present a review of the current diagnostic tests available for making an early diagnosis of CP. We further report our approach to patients suspected of having CP based on the available literature.

Prediction of acute pancreatitis risk based on PIP score in children with cystic fibrosis

BACKGROUND

Currently no tools to predict risk of acute (AP) and recurrent pancreatitis (ARP) in children with cystic fibrosis (CF) are available. We assessed the prevalence of AP/ARP and tested the potential role of Pancreatic Insufficiency Prevalence (PIP) score in a cohort of children with CF.

METHODS

We identified two groups of children, on the basis of presence/absence of AP/ARP, who were compared for age at diagnosis, clinical features, genotypes and sweat chloride level. PIP score was calculated for each patient.

RESULTS

10/167 (5.9%) experienced at least one episode of AP during follow up; 10/10 were pancreatic sufficient (PS). Patients with AP/ARP showed a PIP score ≤0.25 more frequently (6/10) than patients without AP/ARP. The odds ratio (95% CI) of developing pancreatitis was 4.54 (1.22-16.92) for patients with PIP <0.25 when compared with those who have a PIP score >0.25 (p 0.0151). PIP score was correlated with sweat chloride test (p < 0.01).

CONCLUSION

PIP score, PS status and normal/borderline sweat chloride levels could be applied to predict pancreatitis development in children with CF. ARP could lead to pancreatic insufficiency.

Contrasts and comparisons between childhood and adult onset acute pancreatitis

Acute pancreatitis (AP) in children is an increasingly recognised clinical entity notably different from the adults with respect to incidence, aetiology, severity and outcome. Yet our current understanding and approach to the management of paediatric pancreatitis is based almost entirely on adult studies. Acute recurrent pancreatitis (ARP) in children is more likely associated with various genetic factors, some of which have been relatively well characterised and others are in an evolving phase. The aim of this review is to summarise current knowledge, highlight any recent advances and contrast the paediatric and adult forms of this condition.

Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations in pancreatitis

BACKGROUND

The pancreas is one of the primary organs affected by dysfunction of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. While exocrine pancreatic insufficiency is a well-recognized complication of cystic fibrosis (CF), symptomatic pancreatitis is often under-recognized.

RESULTS

The aim of this review is to provide a general overview of CFTR mutation-associated pancreatitis, which affects patients with pancreatic sufficient CF, CFTR-related pancreatitis, and idiopathic pancreatitis. The current hypothesis regarding the role of CFTR dysfunction in the pathogenesis of pancreatitis, and concepts on genotype-phenotype correlations between CFTR and symptomatic pancreatitis will be reviewed. Symptomatic pancreatitis occurs in 20% of pancreatic sufficient CF patients. In order to evaluate genotype-phenotype correlations, the Pancreatic Insufficiency Prevalence (PIP) score was developed and validated to determine severity in a large number of CFTR mutations. Specific CFTR genotypes are significantly associated with pancreatitis. Patients who carry genotypes with mild phenotypic effects have a greater risk of developing pancreatitis than patients carrying genotypes with moderate-severe phenotypic consequences at any given time.

CONCLUSIONS

The genotype-phenotype correlation in pancreatitis is unique compared to other organ manifestations but still consistent with the complex monogenic nature of CF. Paradoxically, genotypes associated with otherwise mild phenotypic effects have a greater risk for causing pancreatitis; compared with genotypes associated with moderate to severe disease phenotypes. Greater understanding into the underlying mechanisms of disease is much needed. The emergence of CFTR-assist therapies may potentially play a future role in the treatment of CFTR-mutation associated pancreatitis.

Genetic prevalence and characteristics in children with recurrent pancreatitis

AIMS

The causes of chronic (CP) and recurrent acute pancreatitis (RAP) in children include anatomic abnormalities and hereditary, metabolic, and autoimmune disorders, with a significant proportion of cases being labeled as idiopathic. Genetic pancreatitis (GP) is associated with mutations of cystic fibrosis transmembrane conductor regulator gene (CFTR), cationic trypsinogen (PRSS1) gene, and serine protease inhibitor Kazal type 1 (SPINK1). There literature is sparse regarding the clinical profile of GP in children. The aim of the present study was to estimate the prevalence and describe the clinical characteristics and outcome of genetic pancreatitis.

METHODS

We reviewed the charts of children ages 18 years or younger with RAP or CP diagnosed from 2000 to 2009 at the Children's Hospital of Wisconsin, Milwaukee. Twenty-nine patients with RAP or CP were identified, of whom 23 (79%) were positive for mutations in ≥1 of the above-mentioned genes, and were included for review.

RESULTS

The median age of symptom onset was 5 years (range 9 months-15 years) with diagnosis at 6.5 years (range 1-16 years). Twenty-one were white; 14 were girls. The most common presenting symptoms were abdominal pain and vomiting. Patients with RAP had 2 to 8 episodes of pancreatitis during 3.6-year average follow-up. Family history was positive in 5 of 29 of gene-tested patients. CFTR, SPINK1, or PRSS1 mutations were seen in 14 (48%), 8 (27%), and 7 (24%) patients, respectively. Two patients were homozygous for CFTR mutations, 6 heterozygote and 4 patients had 5 T variants. Two other patients had double heterozygous mutations in F508 del/2789 + 5G > A and F508 del/5T variant. Six patients with CP had a combination of CFTR and SPINK1 or PRSS1 mutations. Eleven of 29 (38%) patients met radiological criteria for CP. All of the heterozygote patients with a combination of CFTR and SPINK1 or PRSS1 mutations had CP. Eight patients developed a chronic pain syndrome and 2 developed exocrine pancreatic insufficiency during follow-up.

CONCLUSIONS

We found a high prevalence of genetic mutations in patients without anatomic or metabolic abnormalities known to be associated with pancreatitis. Studies are needed to ascertain the genetic causes of RAP and CP and examine the relation between single CFTR mutations and single mutations in the PRSS1 and SPINK1 genes.

Chronic pancreatitis

Chronic pancreatitis is a progressive fibroinflammatory disease that exists in large-duct (often with intraductal calculi) or small-duct form. In many patients this disease results from a complex mix of environmental (eg, alcohol, cigarettes, and occupational chemicals) and genetic factors (eg, mutation in a trypsin-controlling gene or the cystic fibrosis transmembrane conductance regulator); a few patients have hereditary or autoimmune disease. Pain in the form of recurrent attacks of pancreatitis (representing paralysis of apical exocytosis in acinar cells) or constant and disabling pain is usually the main symptom. Management of the pain is mainly empirical, involving potent analgesics, duct drainage by endoscopic or surgical means, and partial or total pancreatectomy. However, steroids rapidly reduce symptoms in patients with autoimmune pancreatitis, and micronutrient therapy to correct electrophilic stress is emerging as a promising treatment in the other patients. Steatorrhoea, diabetes, local complications, and psychosocial issues associated with the disease are additional therapeutic challenges.

Type of CFTR mutation determines risk of pancreatitis in patients with cystic fibrosis

BACKGROUND & AIMS

Different mutations in the cystic fibrosis gene (CFTR) are associated with different functional status of the exocrine pancreas. We investigated whether CFTR genotypes determine the risk of pancreatitis in patients with cystic fibrosis (CF).

METHODS

Patients with pancreatic-sufficient CF were identified from 2 CF population-based databases (N = 277; 62 with pancreatitis and 215 without pancreatitis); patients' genotypes and clinical characteristics were analyzed. The loss of pancreatic function associated with each CFTR genotype was determined based on the pancreatic insufficiency prevalence (PIP) score.

RESULTS

Patients with pancreatitis were more likely to have genotypes associated with mild (70%) than moderate-severe (30%) PIP scores (P = .004). The cumulative proportion of patients who developed pancreatitis through to the age of 50 years was significantly greater for genotypes associated with mild (50%) than moderate-severe (27%) PIP scores (P = .006). The genotype associated with mild PIP scores had a hazard ratio of 2.4 for pancreatitis (95% confidence interval, 1.3-4.5; P = .006). Patients with pancreatitis were diagnosed with CF at an older median age than those without pancreatitis (14.9 years [interquartile range, 9.5-27.7] vs 9.3 years [interquartile range, 1.5-21.4]; P = .003) and had lower mean levels of sweat chloride than patients without pancreatitis (74.5 ± 26.2 mmol/L vs 82.8 ± 25.2 mmol/L; P = .03).

CONCLUSIONS

Specific CFTR genotypes are significantly associated with pancreatitis. Patients with genotypes associated with mild phenotypic effects have a greater risk of developing pancreatitis than patients with genotypes associated with moderate-severe phenotypes. This observation provides further insight into the complex pathogenesis of pancreatitis.