Truninger Kaspar, Witt Heiko, Köck J, Kage Andreas, Seifert B, Ammann Rudolf W, Blum Hubert E, Becker Michael
Department of Medicine II, University of Freiburg, Germany.
Am J Gastroenterol. 2002 May;97(5):1133-7. doi: 10.1111/j.1572-0241.2002.05673.x.
The pathogenesis of chronic pancreatitis (CP) is poorly understood. Genetic studies revealed mutations in the cationic trypsinogen gene and an increased frequency of cystic fibrosis gene mutations in patients with CP. Recently, a point mutation (N34S) in the gene encoding the serine protease inhibitor, Kazal type 1 (SPINK1), was found in approximately 20% of patients with CP. The aim of our study was to determine the frequency of the N34S SPINKI gene mutation in a well-defined patient cohort with idiopathic CP (ICP) and to compare the incidence with healthy controls. In addition, we investigated the impact of this mutation on the long-term course of CP.
Fourteen patients with early-onset and four patients with late-onset CP of our well-defined pancreatitis cohort were enrolled in the present study, and 397 healthy individuals served as a control population. Coding exonic and the flanking intronic sequences of SPINK1 were investigated by direct DNA sequencing. The mutations found were confirmed by melting curve analysis. In addition, the N34S mutation was detected by analyzing the DNA fragments generated by digestion with restriction enzyme TspR I. Clinical data of patients with the N34S mutation were compared with those without mutations.
The N34S mutation was detected in six of 14 (43%) patients with early-onset ICP. One patient was homozygous, and five patients were heterozygous for this mutation. The N34S mutation in a heterozygous state was found in four of 397 healthy controls (1.0%). The different allele frequency observed (seven of 28 vs four of 794) was significant (odds ratio = 66, 95% CI = 18-242, p < 0.0001). The clinical course was similar in patients with a mutation compared with those without a mutation. No other SPINKI mutations were detected. The N34S mutation was not found in patients with late-onset ICP.
Our results indicate that the N34S mutation in the SPINKI gene is strongly associated with ICP, especially with the early-onset type. The natural course is similar in patients with mutations compared with SPINK1 mutation-negative patients. The N34S mutation may easily be screened for by restriction digestion with TspR I.
慢性胰腺炎（CP）的发病机制尚不清楚。基因研究显示，CP患者中阳离子胰蛋白酶原基因突变以及囊性纤维化基因突变频率增加。最近，在约20%的CP患者中发现了编码丝氨酸蛋白酶抑制剂Kazal 1型（SPINK1）的基因发生点突变（N34S）。我们研究的目的是确定在一组明确的特发性CP（ICP）患者队列中N34S SPINK1基因突变的频率，并与健康对照者的发生率进行比较。此外，我们还研究了这种突变对CP长期病程的影响。
我们明确的胰腺炎队列中的14例早发性CP患者和4例迟发性CP患者纳入本研究，397名健康个体作为对照人群。通过直接DNA测序研究SPINK1的编码外显子及其侧翼内含子序列。通过熔解曲线分析确认发现的突变。此外，通过分析用限制性内切酶TspR I消化产生的DNA片段检测N34S突变。将有N34S突变患者的临床数据与无突变患者的临床数据进行比较。
在14例早发性ICP患者中有6例（43%）检测到N34S突变。1例患者为纯合子，5例患者为该突变的杂合子。在397名健康对照者中有4例（1.0%）发现杂合状态的N34S突变。观察到的不同等位基因频率（28个中的7个与794个中的4个）具有显著性（优势比=66，95%可信区间=18 - 242，p<0.0001）。有突变的患者与无突变的患者临床病程相似。未检测到其他SPINK1突变。在迟发性ICP患者中未发现N34S突变。
我们的结果表明SPINK1基因中的N34S突变与ICP密切相关，尤其是早发性类型相关突变患者与SPINK1突变阴性患者的自然病程相似。用TspR I进行限制性消化可轻松筛查N34S突变。
