# A De Novo CaSR Missense Variant in Combination with Two Inherited Missense Variants in CFTR and SPINK1 Detected in a Patient with Chronic Pancreatitis

## TL;DR

A patient with chronic pancreatitis was found to have three genetic variants, including a new one, that may contribute to the disease.

## Contribution

Identification of a de novo pathogenic variant in CaSR alongside inherited variants in CFTR and SPINK1 in a chronic pancreatitis case.

## Key findings

- A de novo CaSR variant (p.Phe790Ser) was classified as likely pathogenic.
- Two inherited variants in CFTR and SPINK1 were identified but had uncertain or benign significance.
- Rare variants in multiple genes may interact to cause chronic pancreatitis.

## Abstract

Chronic pancreatitis is often secondary to alcohol abuse, but pancreatitis with no other aetiology is frequently associated with variants in genes encoding proteins related to zymogen granule activation. Our goal was to identify genomic variants in a patient by analyzing an extended panel of genes associated with the intra-pancreatic activation of the trypsin pathway. A 23-year-old woman was addressed at our institution because of chronic pancreatitis of unknown aetiology presenting recurrent episodes since she was the age of four. Next Generation Sequencing was performed to analyze a panel of nine genes associated with pancreatitis (CaSR, CFTR, CPA1, CTRC, CTSB, KRT8, PRSS1, PRSS2, and SPINK1). Three missense variants were found: p.Leu997Phe, maternally inherited, in the CFTR gene; p.Ile73Phe, paternally inherited, in the SPINK1 gene; and p.Phe790Ser, a de novo variant, in the CaSR gene. They were classified, respectively as probably benign, a Variant of Uncertain Significance, and the last one, which has never been described in the literature, as likely being pathogenic following American College of Medical Genetics and Genomics standard guidelines. Extensive intra-pancreatic activation of trypsin pathway gene sequencing detected rare variants that were not found with other gene screening and showed that variants in different genes may interact in contributing to the onset of the pancreatitis phenotype.