Our findings suggest protein structural changes in the N34S variant as an impairment of SPINK1 and environmental pH shift as a trigger that could play a role in disease progression of pancreatitis.
No further SPINK1 p.N34S (n=4) mutations were detected but the probability of either CTRC or SPINK1 mutations in pHPT patients with pancreatitis is high (P<0.05).
The SPINK-1/N34S mutation predisposes to early onset IP and more frequent acute flares of pancreatitis that might ultimately lead to pancreatic insufficiency.
Four of 25 patients with pHPT and pancreatitis carried the N34S missense mutation in the SPINK1 gene (16%), while all 50 controls (pHPT without pancreatitis) showed no mutation in SPINK1 or PRSS1 genes (P < 0.05 vs controls, P < 0.001 vs general population).
Again, only the patient with the combination of both CASR and N34S SPINK1 gene mutation developed pancreatitis, whereas in the healthy parents and children only an isolated CASR or N34S SPINK1 gene mutation could be detected.
Five mutations (R122H, N29I, A16V, D22G and K23R) in cationic trypsinogen and two mutations (N34S and M1T) in the PSTI/SPINK1 gene have been found to correlate significantly with the onset of pancreatitis.
The N34S mutation was found in six familial pancreatitis patients (three families) and in one juvenile pancreatitis patient, and the R67C mutation was found in one familial pancreatitis patient and one juvenile pancreatitis patient.
Mechanisms other than the conformational change of PSTI associated with amino-acid substitution, such as abnormal splicing, may underlie the predisposition to pancreatitis in patients with the N34S mutation.
Segregation of the N34S mutation in families with pancreatitis is unexplained and points to a complex association between N34S and another putative pancreatitis related gene.