遗传性高非结合性胆红素血症患者的UGT1A1基因突变谱和临床表型的关系

Correlation between the mutation spectrum of the UGT1A1 gene and clinical phenotype in patients with in herited hyperunconjugated bilirubinemia

目的分析遗传性高非结合性胆红素血症患者尿苷二磷酸葡萄糖醛酸转移酶(UGT1A1)突变基因(包括增强子、启动子、外显子1~5)分布特征,探讨UGT1A1基因型与临床表型的关系。方法回顾性分析2015年6月至2022年12月在南京市第二医院诊断为遗传性高非结合性胆红素血症的患者资料。患者均采用Sanger测序对UGT1A1基因进行检测,完成血常规、肝生物化学、腹部影像学检查。分类变量资料比较采用χ^(2)检验或fisher精准检验;正态分布连续变量资料比较用t检验。结果112例(男:女为81:31,年龄9~70岁)遗传性高非结合性胆红素血症患者,共查出14个突变位点,7个为已证实的突变,频率由高到低;(TA)n占50%、c.211G>A(p.G71R)占49.10%、1456T>G(p.Y486D)占16.96%、C.686C>A(p.R229W)占12.5%、1091C>T(p.P364L)占8.04%、C.-3279T>G占0.982%。所有患者同时存在1~4个突变,其中只有1个突变病例最多见(55.36%),其次为2个突变(37.5%),3和4个突变较为少见(分别为5.36%,1.78%);4组间总胆红素(TBil)水平差异无统计学意义(F=0.652,P=0.583)。一个突变以(TA)n和c.211G>A(p.G71R)最多见,其中TA6/TA7(n=10)与TA7/TA7(n=14)突变患者TBil差异有统计学意义(t=2.143,P=0.043)。c.211G>A(p.G71R)杂合(n=9)与纯合(n=15)突变的TBil差异无统计学意义(t=0.382,P=0.706)。GS组占75%,中间组占16.9%,CNS-ⅡI组占8%,3组TBil差异有统计学意义(F=270.992,P<0.001);GS组、中间组、CNS-Ⅱ组中1个突变(分别为44、14、4例)与2个突变(分别为40、5、5例)差异无统计学意义(χ^(2)=3.317,P=0.19)。结论遗传性高非结合性胆红素血症患者UGT1A1基因变异位点数量对TBil水平可能无叠加作用。TA7/TA7突变并不少见,TBil水平较高。

Objective To analyze the distribution characteristics of UGT1Al mutant genes(including enhancers,promoters,and exons 1-5)and further explore the correlation between UGT1A1 genotype and clinical phenotypes in patients with inherited hyperunconjugated bilirubinemia.Methods Patients diagnosed with hereditary hyperunconjugated bilirubinemia at Nanjing Second Hospital from June 2015 to December 2022 were retrospectively analyzed.The UGT1A1 gene was examined using Sanger sequencing in all patients.Complete blood count,liver function,and abdominal imaging examinations were performed.Comparison of categorical variable data using χ^(2) testor Fisher percision tests.Comparison of continaous veriable data with normal distribution using t-test.Results112 cases(male:female ratio 81:31,aged 9-70 years)had inherited hyperunconjugated bilirubinemia,with a total of 14 mutation sites identified,of which seven were confirmed mutations,and the frequency ranged from high to low:(TA)n accounted for 50%,c.211G>A(p.G71R)accounted for 49.10%,1456T>G(p.Y486D)accounted for 16.96%,c.686C>A(p.R229W)accounted for 12.5%,1091C>T(p.P364L)accounted for 8.04%,and c-3279T>G accounted for 0.982%.Simultaneously,all patients had one to four mutations,of which only one mutation was the most common(55.36%),followed by two mutations(37.5%),and rare three and four mutations(5.36%and 1.78%).There was no statistical significance in total bilirubin(TBil)levels among the four groups(F-0.652,P-0.583).One mutation was most common in(TA)n and c.211G>A(p.G71R),among which TA6/TA7(n=10)and TA7/TA7(n=14)mutations were statistically significant in TBil(t-2.143,P-0.043).The c.211G>A(p.G71R)heterozygous(n=9)and isolated(n=15)mutation had no statistical significance in TBil(t-0.382,P-0.706).The GS group accounted for 75%,the intermediate group accounted for 16.9%,and the CNS-II group accounted for 8%.TBil was statistically significant among the three groups(F-270.992,P<0.001).There was no statistically significant difference(χ^(2)=-3.317,P-0.19)between mutation 1(44 cases,14 cases,and 4 cases,respectively)and mutations≥2(40 cases,5 cases,and 5 cases,respectively)in the GS group,intermediate group,and CNS-II group.Conclusion The number ofUGT1A1 gene mutation sites may have no synergistic effect on TBil levels in patients with inherited hyperunconjugated bilirubinemia.TA7/TA7 mutations are not uncommon,and TBil levels are relatively high.