Genetic Testing in Children with Recurrent and Chronic Pancreatitis

Novel chymotrypsin C (CTRC) variants from real-world genetic testing of pediatric chronic pancreatitis cases

BACKGROUND

Chymotrypsin C (CTRC) protects the pancreas against unwanted intrapancreatic trypsin activity through degradation of trypsinogen. Loss-of-function CTRC variants increase the risk for chronic pancreatitis (CP). The aim of the present study was to characterize novel CTRC variants found during genetic testing of CP cases at a pediatric pancreatitis center.

METHODS

We used next-generation sequencing to screen patients. We analyzed the functional effects of CTRC variants in HEK 293T cells and using purified enzymes.

RESULTS

In 5 separate cases, we detected 5 novel heterozygous CTRC variants: c.407C>T (p.Thr136Ile), c.550G>A (p.Ala184Thr), c.627Cdup (p.Ser210Leufs∗?, where the naming indicates a frame shift with no stop codon), c.628T>C (p.Ser210Pro), and c.779A>G (p.Asp260Gly). Functional studies revealed that with the exception of p.Ser210Leufs∗?, the CTRC variants were secreted normally from transfected cells. Enzyme activity of purified variants p.Thr136Ile, p.Ala184Thr, and p.Asp260Gly was similar to that of wild-type CTRC, whereas variant p.Ser210Pro was inactive. The frame-shift variant p.Ser210Leufs∗? was not secreted but accumulated intracellularly, and induced endoplasmic reticulum stress, as judged by elevated mRNA levels of HSPA5 and DDIT3, and increased mRNA splicing of XBP1.

CONCLUSIONS

CTRC variants p.Ser210Pro and p.Ser210Leufs∗? abolish CTRC function and should be classified as pathogenic. Mechanistically, variant p.Ser210Pro directly affects the amino acid at the bottom of the substrate-binding pocket while the frame-shift variant promotes misfolding and thereby blocks enzyme secretion. Importantly, 3 of the 5 novel CTRC variants proved to be benign, indicating that functional analysis is indispensable for reliable determination of pathogenicity and the correct interpretation of genetic test results.

Pancreatitis in pre-adolescent children: a 10 year experience in the pediatric emergency department

Background

The diagnosis of pediatric pancreatitis has been increasing over the last 15 years but the etiology of this is uncertain. The population of pre-adolescent patients with pancreatitis in the emergency department has not been specifically described. Our objective was to determine the characteristics of these patients to illuminate this population and disease in order to better identify them and avoid a delay in diagnosis and treatment.

Methods

This was a retrospective descriptive study of consecutive pediatric patients under the age of 13 years between 2006 and 2016 who presented to our pediatric emergency department with a diagnosis of atraumatic pancreatitis. Patient characteristics, lab and imaging results, identified etiology of pancreatitis, and recurrence rates were recorded and evaluated.

Results

There were 139 visits, of which 85 were for a first episode of acute pancreatitis, and 54 were patients with an episode of recurrent pancreatitis. The median age for all visits was 8 years (IQ range 5–11). Of the acute cases, 26% had uncertain or undetermined etiologies of which half were thought to likely be viral related; 20% had systemic inflammatory or autoimmune diseases; 19% were associated with medications, with the most common being valproic acid; 16% were cholelithiasis-related; and 15% were found to have a genetic, congenital or structural etiology. No patients had elevated triglycerides. Those with cholelithiasis and genetic or structural defects were found to have a higher recurrence rate than those with other etiologies. There were only four patients diagnosed with chronic pancreatitis.

Conclusions

The etiology of pancreatitis in pre-adolescent children has a different distribution than in adolescents and adults, with gallstone disease less frequent and concurrent contributing illness more common. Patients on pancreatitis-causing medications or with known genetic risk or structural pancreatic problems should be tested for pancreatitis if presenting with concerning symptoms. Hypertriglyceridemia and chronic pancreatitis with evidence of pancreatic exocrine insufficiency is uncommon in this population.

Genetic variants in acute, acute recurrent and chronic pancreatitis affect the progression of disease in children

BACKGROUND/OBJECTIVES

Acute pancreatitis (AP) is emerging in pediatrics. A subset of children with AP progresses to acute recurrent pancreatitis (ARP) and chronic pancreatitis (CP). The role of extensive gene testing in the progression has not been investigated previously. We have followed children enrolled in the registry and at our center for progression to ARP and CP after the first attack.

METHODS

This study utilizes an extensive gene sequencing panel as a platform to evaluate the role of genetics in first attack AP, and the progression over time, from first attack to ARP and CP in children.

RESULTS

Genes, with corresponding variants were involved in the 3 groups studied: AP, ARP and CP. We have shown that the presence of gene variants from the eight tested genes is enriched in the CP group compared to the AP and ARP groups. The presence of more than one gene was associated with CP (p = 0.01). SPINK1 mutation(s) was significantly associated with faster progression to ARP, (p = 0.04). Having a variant from CFTR, SPINK1 or PRSS1, was associated with the faster progression from AP to CP over time (p < 0.05).

CONCLUSIONS

This study shows that genetics have a significant role in progression to ARP and CP from the first attack of pancreatitis.

Epidemiology of Pediatric Acute Pancreatitis in Taiwan: A Nationwide Population-based Study

OBJECTIVE

Pediatric acute pancreatitis (AP) may be different from adult AP in various respects. This study focuses on the epidemiology and medical resource use of pediatric AP in Taiwan.

METHODS

Patients aged 0 to 18 years with AP were identified from the Taiwan National Health Insurance Research Database based on the International Classification of Diseases, Ninth Revision code of AP 577.0. The medical resource use was measured by length of hospital stay and hospital charges.

RESULTS

Between 2000 and 2013, a total of 2127 inpatient cases of pediatric AP were collected, which represented a hospitalization rate of 2.83 per 100,000 population. The incidence by age had 2 peaks, the first peak was at age 4 to 5 years old, and the second one started rising from 12 to 13 years old until adulthood. The incidence by year increased from 2.33 to 3.07 cases per 100,000 population during the study period. The average hospital stay is steady, but the medical cost is increasing. Girls have longer hospital stays, higher medical expenditures, more use of endoscopic retrograde cholangiopancreatography possibly due to more comorbidities with biliary tract diseases than boys (P < 0.05). The mortality in cases of AP is mostly associated with systemic diseases rather than AP itself.

CONCLUSIONS

The incidence of pediatric AP in Taiwan is in a rising trend. There are gender differences in length of hospital stay, medical costs, use of endoscopic retrograde cholangiopancreatography and comorbidities.

Pediatric chronic pancreatitis: Updates in the 21st century

Pediatric Pancreatitis has gained a lot of attention in the last decade. Updates in medical management include new testing technologies in genetics, function testing and imaging modalities. Updates in surgical management have taken place as well, with total pancreatectomy islet auto transplantation reserved for a specific patient population that meets the clinical criteria. Multidisciplinary team management is needed for patients with chronic pancreatitis to ensure optimal outcomes.