Do PRSS1/PRSS2 variants increase pancreatitis risk and cause protein malabsorption?

Genetic variants at the PRSS1 and PRSS2 loci are well-established drivers of pancreatic health, primarily by regulating the balance and activity of trypsinogen, the precursor to the master digestive enzyme trypsin.

Genetic susceptibility and protease biology

The PRSS1-PRSS2 gene cluster encodes cationic and anionic trypsinogen. Variants in this region, particularly the rs10273639 single nucleotide polymorphism (SNP), function as expression quantitative trait loci (eQTLs) that significantly influence susceptibility to chronic pancreatitis.

• Mechanistic findings: These variants modulate the "trypsinogen-to-trypsin" balance. For instance, gain-of-function mutations (such as p.R122H) or variants that increase PRSS1 expression lead to premature intra-pancreatic trypsin activation. This triggers a cascade of autodigestion and inflammation, a hallmark of pancreatitis.
• Risk metrics: Meta-analyses demonstrate that the PRSS1-PRSS2 locus is one of the most potent genetic risk factors for both alcoholic and non-alcoholic pancreatitis, with odds ratios (OR) typically ranging from 1.3 to 1.6 (p < 10⁻²⁰).

Impact on digestive capacity and malabsorption

The transition from genetic susceptibility to clinical malabsorption occurs through the development of Exocrine Pancreatic Insufficiency (EPI).

• Clinical evidence: Chronic inflammation and repeated injury driven by these protease variants lead to the progressive replacement of functional acinar cells with fibrotic tissue. Trypsin is critical because it acts as the primary activator for all other pancreatic zymogens, including chymotrypsin and elastase.
• Protein malabsorption: When enzyme secretion falls below approximately 10% of normal capacity, significant malabsorption occurs. While fat malabsorption is often the most visible symptom, protein malabsorption (azotorrhea) is a documented consequence of reduced trypsin capacity. Clinical studies in patients with chronic pancreatitis frequently show reduced fecal elastase-1 levels and nitrogen balance issues, reflecting an inability to break down dietary proteins into absorbable amino acids.
• Vulnerability factors: In individuals with these genetic variants, the risk of malabsorption is further exacerbated by environmental stressors like alcohol or tobacco, which can accelerate the decline in digestive enzyme production.

Bottom line

Variants near PRSS1/PRSS2 are scientifically supported drivers of pancreatitis risk through the dysregulation of trypsin activity. This altered biology can lead to a functional loss of pancreatic tissue, significantly reducing digestive enzyme capacity and causing protein malabsorption in susceptible individuals.