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As a bilirubin metabolic disorder, Gilbert syndrome belongs to the category of congenital non-hemolytic jaundice. Deficiency or decrease in the activity of bilirubin-uridine diphosphate glucuronyltransferase (UGT) is an important reason for the pathogenesis of Gilbert syndrome. UGT1A1, an isoenzyme of UGT, is a key enzyme to direct bilirubin in the liver. Mutations in UGT1A1 gene lead to the structural abnormality of UGT, and thus result in the decrease or loss of the ability of UGT to bind bilirubin. This article summarizes the research advances in the role of UGTA1 and its polymorphism in the pathogenesis and diagnosis of Gilbert syndrome. [ABSTRACT FROM AUTHOR]

Hyperbilirubinemia is a prevalent disease in neonates and is also a main reason for hospitalization within the first week after birth, and this disease is mainly caused by the imbalance between production and elimination of bilirubin. Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1), organic anion transporter polypeptide 2 (OATP2), heme oxygenase 1 (HO-1), and biliverdin reductase A (BLVRA) play crucial roles in the metabolism of bilirubin. More and more studies have revealed the association between the variation of the encoding genes for these enzymes and hyperbilirubinemia. This article reviews the research advances in the association between the gene polymorphisms of bilirubin metabolic enzymes and hyperbilirubinemia.

Objective: To compare and analyze patient's general condition, changes in laboratory parameters, and the spectrum of UGT1A1 mutations in patients with inherited non-hemolytic unconjugated hyperbilirubinemia. Methods: A retrospective study was conducted at Nanjing Second Hospital from January 2015 to July 2018 and patients' demographic characteristics, liver function test, and UGT1A1 gene were analyzed. The categorical variable data were compared by χ (2) test. The normal distribution continuous variable data were compared by t-test and the non-normal distribution continuous variable data were compared using Mann-Whitney U test. Results: Of the 51 patients with inherited non-hemolytic unconjugated hyperbilirubinemia, 44 (86.3%) were Gilbert's syndrome (GS) and seven (13.7%) were Crigler-Najjar syndrome type II (CNS- II). The male to female ratio was 2.9:1 and the average age was 36.11 ± 13.17 years. Six variant types were detected: C. -40&#95;-39insTA, C. -3279T > G, c.211G > A (p.G71R), c.686C > A (p.P229Q), c.1091C > T (p.P364L), c.1456T > G (P.Y486D). Among them, c.211G > A accounted for 58.82% (30/51), c.-40&#95;-39insTA accounted for 27.5% (14/51), and c.1456T > G accounted for 25.5% (13/51). The total bilirubin(TB) and unconjugated bilirubin (UCB) in CNS-II patients were significantly higher than GS patients[155.91 (130 ~ 207) vs. 38.25(29 ~ 52.15) μmol/L, U = 0, P < 0.01; 144.13 (120.8 ~ 197) vs. 30.00 (21.7 ~ 46.75) μmol/L, U = 0.00, P < 0.01, respectively]. Exon mutations of c.1091C > T and c.1456T > G were statistically significant( P < 0.01).There were no differences in age, TB, UCB, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) between the c.211G > A homozygous variants and heterozygous variants ( P > 0.05). Conclusion: The common pathogenic mutations of UGT1A1 gene were c.211G > A, c.-40&#95;-39insTA, c.1456T > G. c.211G > A. The mutation has little effect on the level of total bilirubin, but c.1091C > T, c.1456T > G mutations has great influence on the level of total bilirubin.

Objective: To evaluate the association between single nucleotide polymorphisms (SNPs) of RS1826690 located in UGT2B4 gene and pathological complete response (pCR) to neoadjuvant chemotherapy in breast cancer patients. Methods: A total of 146 breast cancer patients were enrolled to detect the SNPs of RS1826690 by sequenom. The relationship between SNPs of RS1826690 and pCR, predictors of pCR were analyzed by univariate or multivariate analysis. Results: The frequency of CC, CT and TT genetype of RS1826690 was 20.6%, 39.7% and 39.7%, respectively. Of the 171 patients, pCR was achieved in 39 cases (26.7%), with CC allele in 14 cases, CT allele in 7 cases and TT allele in 18 cases, and statistically significant difference was observed (χ(2)=16.684, P =0.003). Multivariate logistic regression analysis showed that SNPs of RS1826690 was an independent predictor of pCR (95% CI: 2.311-28.810, P =0.001) . SNPs of RS1826690 was statistically associated with estrogen receptor (ER) status (χ(2)=7.872, P =0.020). Conclusion: SNPs of RS1826690 was associated with pCR, and breast cancer patients with CC allele were more likely to achieve pCR.

Objective: To analyze the 5' and 3'-untranslated region sequences of the UGT1A1 gene in Chinese Han population and to find polymorphic variants within the untranslated region., Methods: Genomic DNA was extracted from peripheral leukocytes in 220 healthy Han individuals. The 5' and 3'-untranslated region sequences of the UGT1A1 gene were amplified by polymerase chain reaction, and followed by DNA sequencing., Results: Two polymorphic loci were identified in the 5'-untranslated region of the UGT1A1 gene with -64(G/C) and A(TA)6TAA/A(TA)7TAA in TATAA box region among Chinese Han population. Genotype frequencies were 98.4% (G) and 1.6% (C) in -64 locus of the UGT1A1 gene among the 220 individuals. The allele frequency of A(TA)6TAA and A(TA)7TAA within the promoter region was found to be 93.4% and 6.6%, respectively. Two polymorphic loci of 1813(C/T) and 1941(C/G) were detected in the 3'-untranslated region of the UGT1A1 gene, they showed a homozygous state at two loci with cosegregation pattern at 1813 and 1941 locus. The haplotype frequencies were 73.6% (CC/1813+CC/1941) and 26.4% (TT/1813+GG/1941) for 1813 and 1941 loci in the UGT1A1 gene., Conclution: Cosegregation pattern, at 1813 and 1941 locus with homozygous state in the 3'-untranslated region of the UGT1A1 gene may be selected from the human genome among Chinese Han population. More studies should be focused on the mechanism of homozygous cosegregation.

Objective: To explore the clinical features and gene mutation profiles of patients with chronic hepatitis B (CHB) and Gilbert's syndrome., Methods: Thirty-three patients with CHB and Gilbert's syndrome were enrolled in the study. Serum markers of liver function and histological features of disease-related liver injury were assessed by standard methods. Gene mutations were detected by PCR and direct DNA sequencing.Statistical analysis was carried out with the chi-square and t tests., Results: Sequencing of the Gilbert syndrome-associated gene, UGT 1A 1, revealed mutations in the upstream promoter phenobarbital-responsive element module (PBREM) (-3279 mutation, 23 cases), in the promoter TATA box (a TA insertion mutation, 21 cases), and in the coding region of exon 1 (a GGA-AGA Gly71Arg mutation, 18 cases); there was no statistical difference found for any of the three mutations among this patient population (x2 =1.640, P more than 0.05)., Conclusion: The traditional methods of diagnosis for patients with CHB and Gilbert's syndrome remain a technical challenge in the clinic, and gene detection may represent a more favorable method for diagnosing this patient population.