TCP is an idiopathic, juvenile, nonalcoholic form of chronic pancreatitis widely prevalent in several tropical countries. Fibrocalculous pancreatic diabetes (FCPD) is a form of diabetes secondary to TCP (Mohan et al., 1989). TCP differs from alcoholic pancreatitis by ... TCP is an idiopathic, juvenile, nonalcoholic form of chronic pancreatitis widely prevalent in several tropical countries. Fibrocalculous pancreatic diabetes (FCPD) is a form of diabetes secondary to TCP (Mohan et al., 1989). TCP differs from alcoholic pancreatitis by a younger age at onset, pancreatic calcification, a high incidence of insulin-dependent but ketosis-resistant diabetes mellitus, and an exceptionally high incidence of pancreatic cancer (Chandak et al., 2002).
In 68 patients from India with clinically and radiologically confirmed TCP (24 with FCPD and 44 with TCP without diabetes mellitus), Chandak et al. (2002) analyzed for mutations in the PRSS1 and SPINK1 genes. No mutation was detected ... In 68 patients from India with clinically and radiologically confirmed TCP (24 with FCPD and 44 with TCP without diabetes mellitus), Chandak et al. (2002) analyzed for mutations in the PRSS1 and SPINK1 genes. No mutation was detected in the PRSS1 gene in these patients. They identified compound heterozygosity for an asn34-to-ser mutation in the SPINK1 gene (N34S; 167790.0001) and a -215G-T promoter mutation that was not found in any of 100 controls. All 3 patients had late-onset disease with diabetes mellitus, consistent with the fibrocalculous pancreatic diabetes phenotype. Of the other patients with TCP, 8 were homozygous for N34S, 22 were heterozygous for N34S, and 1 was heterozygous for N34S and another mutation in the SPINK1 gene. Analysis of the phenotype in terms of the age at onset, frequency of attacks, and presence and age at onset of diabetes mellitus did not show any significant difference between N34S heterozygous or homozygous patients. Because the N34S heterozygous and homozygous patients had a similar phenotype, Chandak et al. (2002) presumed that mutated SPINK1 cannot cause disease independently by autosomal dominant or recessive mechanisms and that the presence of a second mutation, either in the same gene or other genes, is required for expression of the disease phenotype. Mahurkar et al. (2006) found an association between the val26 allele of a leu26-to-val polymorphism (dbSNP rs12338) in the CTSB gene (116810) in patients with tropical calcific pancreatitis; the association appeared to be independent of SPINK1 mutation status, suggesting that val26 may act as a susceptibility allele in the pathogenesis of TCP.