Loss-of-function variant in chymotrypsin like elastase 3B (CELA3B) is associated with non-alcoholic chronic pancreatitis

Background: Genetic alterations in digestive enzymes have been associated with chronic pancreatitis (CP). Recently, chymotrypsin like elastase 3B (CELA3B) emerged as a novel risk gene. Thus, we evaluated CELA3B in two European cohorts with CP. Methods: We analyzed all 8 CELA3B exons in 550 German non-alcoholic CP (NACP) patients and in 241 German controls by targeted DNA sequencing. In addition, we analyzed exons 6 and 7 by Sanger sequencing and the c.129+1G>A variant by melting curve analysis in 1078 further German controls. As replication cohort, we investigated up to 243 non-German European NACP patients and up to 1665 controls originating from Poland, Hungary, and Sweden. We assessed the cellular secretion and the elastase activity of recombinant CELA3B variants. Results: In the German discovery cohort, we detected a splice-site variant in intron 2, c.129+1G>A, in 9/550 (1.64%) CP patients and in 5/1319 (0.38%) controls (P=0.007, OR=4.4, 95% CI=1.5–13.0). In the European replication cohort, this variant was also enriched in patients (9/178 [5.06%]) versus controls (13/1247 [1.04%]) (P=0.001, OR=5.1, 95% CI=2.1–12.0). We did not find the two previously reported codon 90 variants, p.R90C and p.R90L. Conclusions: Our data indicate that CELA3B is a susceptibility gene for CP. In contrast to previous reports suggesting that increased CELA3B activity is associated with CP risk, the splice-site variant identified here is predicted to cause diminished CELA3B expression. How reduced CELA3B function predisposes to pancreatitis remains to be elucidated.