Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of Cincinnati College of Medicine and the Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of Cincinnati College of Medicine and the Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
Gastroenterology. 2018 Jun;154(8):2097-2110. doi: 10.1053/j.gastro.2018.02.016. Epub 2018 Feb 15.
BACKGROUND & AIMS: Individuals with monogenic disorders of phagocyte function develop chronic colitis that resembles Crohn's disease (CD). We tested for associations between mutations in genes encoding reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases, neutrophil function, and phenotypes of CD in pediatric patients.
We performed whole-exome sequence analysis to identify mutations in genes encoding NADPH oxidases (such as CYBA, CYBB, NCF1, NCF2, NCF4, RAC1, and RAC2) using DNA from 543 pediatric patients with inflammatory bowel diseases. Blood samples were collected from an additional 129 pediatric patients with CD and 26 children without IBD (controls); we performed assays for neutrophil activation, reactive oxygen species (ROS) production, and bacteria uptake and killing. Whole-exome sequence analysis was performed using DNA from 46 of the children with CD to examine associations with NADPH gene mutations; RNA sequence analyses were performed using blood cells from 46 children with CD to test for variations in neutrophil gene expression associated with ROS production.
We identified 26 missense mutations in CYBA, CYBB, NCF1, NCF2, and NCF4. Patients with CD who carried mutations in these genes were 3-fold more likely to have perianal disease (P = .0008) and stricturing complications (P = .002) than children with CD without these mutations. Among patients with CD with none of these mutations, 9% had undergone abdominal surgery; among patients with mutations in these NADPH oxidase genes, 31% had undergone abdominal surgery (P = .0004). A higher proportion of neutrophils from children with CD had low ROS production (47%) than from controls (15%) among the 129 patients tested for ROS (P = .002). Minor alleles of the NADPH genes were detected in 7% of children with CD whose neutrophils produced normal levels of ROS vs 38% of children whose neutrophils produced low levels of ROS (P = .009). Neutrophils that produced low levels of ROS had specific alterations in genes that regulate glucose metabolism and antimicrobial responses.
We identified missense mutations in genes that encode NADPH oxidases in children with CD; these were associated with a more aggressive disease course and reduced ROS production by neutrophils from the patients.
具有吞噬细胞功能单基因疾病的个体发生类似于克罗恩病（CD）的慢性结肠炎。我们检测了编码还原型烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶的基因突变、中性粒细胞功能与儿科 CD 患者表型之间的相关性。
我们使用来自 543 例炎症性肠病儿科患者的 DNA 进行全外显子组测序分析，以鉴定编码 NADPH 氧化酶（如 CYBA、CYBB、NCF1、NCF2、NCF4、RAC1 和 RAC2）的基因突变。我们从另外 129 例 CD 儿科患者和 26 例无炎症性肠病（对照）儿童的血液样本中收集了样本；我们进行了中性粒细胞激活、活性氧（ROS）产生、细菌摄取和杀伤的检测。我们使用来自 46 例 CD 患儿的 DNA 进行全外显子组测序分析，以研究与 NADPH 基因突变的关联；我们使用来自 46 例 CD 患儿的血细胞进行 RNA 序列分析，以检测与 ROS 产生相关的中性粒细胞基因表达的变化。
我们在 CYBA、CYBB、NCF1、NCF2 和 NCF4 中鉴定出 26 个错义突变。携带这些基因突变的 CD 患者发生肛周疾病（P=0.0008）和狭窄并发症（P=0.002）的可能性是无这些基因突变的 CD 患儿的 3 倍。在没有这些 NADPH 氧化酶基因突变的 CD 患者中，9%接受了腹部手术；而在这些 NADPH 氧化酶基因突变的患者中，31%接受了腹部手术（P=0.0004）。在 129 例接受 ROS 检测的患者中，与对照组（15%）相比，CD 患儿的中性粒细胞 ROS 产生水平较低（47%）（P=0.002）。在产生正常水平 ROS 的 CD 患儿中，检测到 NADPH 基因的次要等位基因占 7%，而在产生低水平 ROS 的患儿中，检测到 NADPH 基因的次要等位基因占 38%（P=0.009）。产生低水平 ROS 的中性粒细胞在调节葡萄糖代谢和抗菌反应的基因中有特定的改变。
我们在 CD 患儿中鉴定出编码 NADPH 氧化酶的基因突变；这些突变与更具侵袭性的疾病过程和患者中性粒细胞 ROS 产生减少有关。
