[Clinicopathological and molecular genetic features of Crohn's disease].

Objective: To investigate the clinicopathological and molecular genetic characteristics of Crohn's disease (CD). Methods: A retrospective analysis was conducted on 52 CD patients who underwent surgical resection at the First Affiliated Hospital of Nanjing Medical University between January 2014 and June 2023. Clinical presentations and histopathological features were assessed. Whole-genome sequencing was performed on 17 of the samples, followed by sequencing and pathway enrichment analyses. Immunohistochemistry was used to assess the expression of frequently mutated genes. Results: Among the 52 patients, 34 were males and 18 were females, male-to-female ratio was 1.9∶1.0, with a median age of 45 years at surgery and 35 years at diagnosis. According to the Montreal classification, A3 (51.9%,27/52), B2 (61.5%, 32/52), and L3 (50.0%,26/52) subtypes were the most predominant. Abdominal pain and diarrhea were the common symptoms. Histopathological features seen in all 52 patients included transmural inflammation, disruption of cryptal architecture, lymphoplasmacytic infiltration, varying degrees of submucosal fibrosis and thickening, increased enteric nerve fibers and neuronal proliferation. Mucosal defects, fissure ulcers, abscesses, pseudopolyps, and adenomatous proliferation were also observed in 51 (98.1%), 38 (73.1%), 28 (53.8%), 45 (86.5%), and 28 (53.8%) cases, respectively. Thirty-one (59.6%) cases had non-caseating granulomas, and 3 (5.8%) cases had intestinal mucosal glandular epithelial dysplasia. Molecular analysis showed that 12/17 CD patients exhibited mutations in at least one mucin family gene (MUC2, MUC3A, MUC4, MUC6, MUC12, MUC17), and MUC4 was the most frequently mutated in 7/17 of cases. Immunohistochemical stains showed reduced MUC4 expression in epithelial cells, with increased MUC4 expression in the epithelial surface, particularly around areas of inflammatory cell aggregation; and minimal expression in the lower half of the epithelium. Conclusions: CD exhibits diverse clinical and pathological features, necessitating a comprehensive multidimensional analysis for diagnosis. Mutations and expression alterations in mucin family genes, particularly MUC4, may play crucial roles in the pathogenesis of CD.目的： 探讨克罗恩病（Crohn′s disease）的临床病理及分子遗传学特征。 方法： 回顾性分析2014年1月至2023年6月在南京医科大学第一附属医院行手术切除的52例克罗恩病患者的临床表现及病理特征，运用全基因组测序方法对其中17例标本进行测序、信号通路富集分析，运用免疫组织化学方法探究高频突变基因的作用。 结果： 52例患者中男性34例，女性18例，男女比例1.9∶1.0，中位手术年龄45岁，中位确诊年龄35岁；根据蒙特利尔分型，A3型（51.9%，27/52）、B2型（61.5%，32/52）及L3型（50.0%，26/52）占比较高；腹痛、腹泻为常见症状。病理学特征：52例均见透壁性炎、隐窝结构的改变、淋巴细胞浆细胞浸润及不同程度的黏膜下层纤维化、增厚，肠壁神经纤维及神经元增生；黏膜缺损51例（98.1%），裂隙性溃疡38例（73.1%），脓肿28例（53.8%），见假息肉形成45例（86.5%），伴幽门腺化生28例（53.8%），见非干酪样肉芽肿31例（59.6%），出现肠黏膜腺上皮异型增生3例（5.8%）。分子生物学特征：MUC4基因突变频率最高（7/17），且12/17克罗恩病中出现至少一个黏蛋白家族基因突变（MUC2、MUC3A、MUC4、MUC6、MUC12、MUC17）。免疫组织化学评分结果提示，克罗恩病中上皮细胞MUC4表达降低，且MUC4阳性细胞更多出现在上皮表面且集中在炎性细胞聚集区周围，而在下1/2层上皮内极少表达。 结论： 克罗恩病的临床病理特征表现多样，其诊断常常需要多角度综合分析；黏蛋白家族基因（尤其是MUC4基因）的突变及表达在克罗恩病中可能发挥了重要作用。.