Goel Ashish, Raghupathy V, Amirtharaj G J, Chapla Aaron, Venkatraman Aparna, Ramakrishna Banumathi, Ramachandran Anup, Thomas Nihal, Balasubramanian K A, Mackie Ian, Elias Elwyn, Eapen Chundamannil E
Department of Hepatology, Christian Medical College, Vellore, 632 004, India.
Department of Wellcome Research Unit, Christian Medical College, Vellore, 632 004, India.
Indian J Gastroenterol. 2017 Sep;36(5):380-389. doi: 10.1007/s12664-017-0786-9. Epub 2017 Oct 5.
Non-cirrhotic intrahepatic portal hypertension (NCIPH) is characterized by thrombotic microangiopathy of the portal venous system, low ADAMTS13 (a disintegrin-like and metalloproteinase with thrombospondin type 1 motifs-13), and high vWF (von Willebrand factor) levels. This study aimed to screen for ADAMTS13 mutations, focusing on the CUB domain, in these patients.
Prospectively recruited NCIPH patients and healthy volunteers underwent tests for plasma vWF-ADAMTS13 balance. Sanger sequencing of the CUB domain of ADAMTS13 was done in a subset of the NCIPH patients, and the detected mutation was screened for in all the study participants. Next-generation sequencing of clinically relevant exome and liver immunostaining for ADAMTS13 was done in patients with detected ADAMTS13 mutation.
Plasma vWF-ADAMTS13 balance was significantly altered in 24 NCIPH patients (Child's class A:23, B:1) as compared to 22 controls. On initial sequencing of the CUB domain (17 cases and 3 controls), one NCIPH patient showed a rare missense variant (SNV) at position c.3829C >T resulting in p.R1277W (rs14045669). Subsequent RFLP analysis targeted to the R1277W variant did not detect this in any other NCIPH patient, nor in any of the 22 controls. The NCIPH patient with the R1277W variant had severe ADAMTS13 deficiency, consistently high vWF, other missense SNVs in ADAMTS13, vWF, and complement genes. Immunostaining of his liver biopsy revealed globules of ADAMTS13 within stellate cells.
We report missense variants in ADAMTS13, vWF, and complement genes in a patient with NCIPH who had decreased secretion and activity of ADAMTS13 protein. Further studies are needed in NCIPH patients in this regard.
非肝硬化性肝内门静脉高压症（NCIPH）的特征是门静脉系统的血栓性微血管病、低ADAMTS13（含Ⅰ型血小板反应蛋白基序的解聚素样金属蛋白酶13）水平和高血管性血友病因子（vWF）水平。本研究旨在筛查这些患者中ADAMTS13的突变情况，重点关注CUB结构域。
前瞻性招募NCIPH患者和健康志愿者，检测其血浆vWF-ADAMTS13平衡。对部分NCIPH患者进行ADAMTS13的CUB结构域的桑格测序，并在所有研究参与者中筛查检测到的突变。对检测到ADAMTS13突变的患者进行临床相关外显子组的二代测序及ADAMTS13的肝脏免疫染色。
与22名对照者相比，24例NCIPH患者（Child分级A：23例，B：1例）的血浆vWF-ADAMTS13平衡发生了显著改变。对CUB结构域进行初次测序（17例患者和3名对照者）时，1例NCIPH患者在c.3829C>T位置出现罕见错义变异（SNV），导致p.R1277W（rs14045669）。随后针对R1277W变异进行的限制性片段长度多态性分析在其他NCIPH患者或22名对照者中均未检测到该变异。携带R1277W变异的NCIPH患者存在严重的ADAMTS13缺乏、持续高水平的vWF、ADAMTS13、vWF和补体基因中的其他错义SNV。其肝脏活检的免疫染色显示星状细胞内有ADAMTS13小球。
我们报告了1例NCIPH患者的ADAMTS13、vWF和补体基因中的错义变异，该患者的ADAMTS13蛋白分泌和活性降低。在这方面，NCIPH患者还需要进一步研究。
