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Signal peptide variants that impair secretion of pancreatic secretory trypsin inhibitor (SPINK1) cause autosomal dominant hereditary pancreatitis
Author(s) -
Király Orsolya,
Boulling Arnaud,
Witt Heiko,
Le Maréchal Cédric,
Chen JianMin,
Rosendahl Jonas,
Battaggia Cinzia,
Wartmann Thomas,
SahinTóth Miklós,
Férec Claude
Publication year - 2007
Publication title -
human mutation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 162
eISSN - 1098-1004
pISSN - 1059-7794
DOI - 10.1002/humu.20471
Subject(s) - biology , pancreatitis , chinese hamster ovary cell , trypsin inhibitor , exon , endocrinology , secretion , trypsin , medicine , pancreatic disease , microbiology and biotechnology , gene , pancreas , genetics , biochemistry , cell culture , enzyme
Variants of the SPINK1 gene encoding pancreatic secretory trypsin inhibitor have been described in association with chronic pancreatitis (CP). These alterations are believed to cause a loss of function by either impairing the trypsin inhibitory activity or reducing expression. Here we report two novel SPINK1 variants in exon 1 that affect the secretory signal peptide. The disease‐associated c.41T>G (p.L14R) alteration was found in two European families with autosomal dominant hereditary pancreatitis, whereas the c.36G>C (p.L12F) variant was identified as a frequent alteration in subjects of African descent. The functional effects of both alterations and the previously reported c.41T>C (p.L14P) variant were characterized by activity assays and Western blots of wild‐type and mutant SPINK1 expressed in human embryonic kidney 293T and Chinese hamster ovary cells. Alterations p.L14R and p.L14P destined the inhibitor for rapid intracellular degradation and thereby abolished SPINK1 secretion, whereas the p.L12F variant showed no detrimental effect. The results provide the first clear experimental demonstration that alterations that markedly reduce SPINK1 expression are associated with classic hereditary pancreatitis. Therefore, these variants should be classified as severe and regarded as disease‐causing rather than disease‐modifiers. Hum Mutat 28(5), 469–476, 2007. Published 2007 Wiley‐Liss, Inc.