SPINK1/PSTI mutations are associated with tropical pancreatitis and type II diabetes mellitus in bangladesh

Abstract

Background & Aims: Tropical pancreatitis, including tropical calcific pancreatitis and fibrocalculous pancreatic diabetes, is endemic in parts of Asia and Africa. In a preliminary study, we found serine protease inhibitor, Kazal type 1 (SPINK1) mutations in 6 of 8 patients with fibrocalculous pancreatic diabetes in Bangladesh. A more extensive investigation of patients with pancreatic diseases in Bangladesh, including non-insulin-dependent diabetes mellitus, was undertaken. Methods: Patients with fibrocalculous pancreatic diabetes (n = 22), tropical calcific pancreatitis (n = 15), and non-insulin-dependent diabetes mellitus (n = 43) and controls (n = 76) from Bangladesh were studied. DNA was extracted, and the SPINK1 gene was sequenced in all patients and 50 controls. Exon 3 was sequenced in an additional 26 controls. Results: SPINK1 N34S mutations appeared in 1 of 76 controls (1.3%), 12 of 22 patients with fibrocalculous pancreatic diabetes (55%; odds ratio, 83; P < 0.00001), 3 of 15 with tropical calcific pancreatitis (20%; odds ratio, 11.2; P = 0.04), and 6 of 43 with non-insulin-dependent diabetes mellitus (14%; odds ratio, 11.9; P = 0.009). P55S was present in 2 of 76 controls (3%) and in 1 of 22 patients with fibrocalculous pancreatic diabetes (5%; P = not significant). A novel Y54H (160T>C) mutation was identified in 1 of 15 tropical calcific pancreatitis patients. Conclusions: In Bangladesh, the SPINK1 N34S mutation increases the risk of several forms of pancreatic disease, including fibrocalculous pancreatic diabetes, tropical calcific pancreatitis, and non-insulin-dependent diabetes mellitus.