Sequence Analysis of the UGT1A1 Gene Untranslated Region in Chinese Han Population / 中国实验血液学杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUTION</b>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.</p>

Mutation analysis of UGT1A1 gene in patients with unconjugated hyperbilirubinemia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To analyze potential mutations of uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) gene in patients with unconjugated hyperbilirubinemia, and to explore the correlation between the mutations and total serum bilirubin levels.</p><p><b>METHODS</b>Genomic DNA was extracted from peripheral blood samples of patients. Coding sequence and promoter region of the UGT1A1 gene were amplified. Mutations were identified through DNA sequencing.</p><p><b>RESULTS</b>Mutations of the UGT1A1 gene were found in 46 out of 61 patients with unconjugated hyperbilirubinemia. Five types of mutations were detected, with a decreasing order of 211G>A, TA insertion in the TATAA promoter element, 686C>A, 1091C>T and 1352C>T. Compared with those carrying a single homozygous mutation or compound heterozygous mutations, total serum bilirubin was higher in those carrying a homozygous mutation in combination with other heterozygous mutations (P< 0.05). Based on the UGT1A1 gene mutations and level of total serum bilirubin, 44 patients were diagnosed with Gilbert syndrome, and 2 were diagnosed with Crigler-Najjar syndrome type 2.</p><p><b>CONCLUSION</b>The level of total serum bilirubin is correlated with the number of UGT1A1 gene mutations as well as their heterozygous or homozygous status.</p>

A novel mutation in β-globin gene of a patient with β-thalassemia / 中国实验血液学杂志

This study was aimed to analyze the β-globin gene mutations in a patient with β-thalassemia minor. Genomic DNA was extracted from peripheral blood cells of the patient. The full-length DNA sequence coding for β-globin was amplified by polymerase chain reaction, and the gene mutation was determined by DNA sequencing. The results indicated that a heterogeneous A→G mutation was found at position 129 in intron 1 of the β-thalassemia minor patient. It is concluded that the IVS-I-129(A→G) mutation is a splicing site mutation leading to a splicing error in immature messenger RNA and a protein translation error for the β-globin gene. Thus, the IVS-I-129(A→G) is a novel mutation.

Correlation between hemoglobin F levels and single nucleotide polymorphism at BCL11A gene rs11886868 locus in β-thalassemia patients / 中国实验血液学杂志

This study was aimed to analyze hemoglobin F (HbF) level and single nucleotide polymorphisms at rs11886868 locus of BCL11A gene in β-thalassemia patients, and to explore correlation between them. 89 mild β-thalassemia patients with known mutations were registered, and HbF levels were determined by capillary electrophoresis. Genomic DNA was extracted from peripheral leukocytes, fragment including rs11886868 locus in BCL11A gene was amplified by PCR, and polymorphism was determined by DNA sequencing. The results showed that 2 polymorphisms including C and T were found at rs11886868 locus in BCL11A gene among 89 mild β-thalassemia patients. HbF levels in red blood cells were (4.47 ± 3.42)% and (2.79 ± 2.21)% for β-thalassemia patients carrying C/C and C/T haplotypes, respectively. There was difference between 2 haplotype groups. It is concluded that the C and T polymorphisms are found at rs11886868 locus in the BCL11A gene for β-thalassemia patients. C polymorphism may be related to high HbF expression in red blood cells.

Polymorphism in BP1 binding site upstream of β-globin gene in Chinese Han population / 中国实验血液学杂志

This study was aimed to analyze the BP1 binding site sequence upstream of β-globin gene in Chinese Han population, and to investigate polymorphism in the BP1 binding site upstream of β-globin gene, so as to provide the basis for exploration of relation between polymorphisms in the BP1 binding site and β-globin expression. Genomic DNA was extracted from peripheral leukocytes of 110 healthy individuals in Chinese Han population. Sequence of the BP1 binding site upstream of β-globin gene was amplified by polymerase chain reaction, the polymorphic variation in the BP1 binding site was determined by DNA sequencing. The results indicated that 2 polymorphism loci were found in the BP1 binding site upstream of β-globin gene, they were C/T at the -551 bp region and (AC)(n)(AT)(x)T(y) at the -530 bp region in Chinese Han population. Frequencies of C and T were 60.4% and 39.6% at position -551. Analysis of the (AC)(n)(AT)(x)T(y) polymorphism revealed 9 different genotypes: (AC)(2)(AT)(9)T(5), (AC)(2)(AT)(8)T(5), (AC)(2)(AT)(7)T(7), (AC)(3)(AT)(7)T(5), (AC)(2)(AT)(8)T(9), (AC)(3)(AT)(8)T(5), (AC)(2)(AT)(10)T(3), (AC)(2)(AT)(11)T(3), and (AC)(2)(AT)(7)T(5) at position -530. Frequencies of 9 (AC)(n)(AT)(x)T(y) polymorphisms were 33.2%, 29.1%, 24.1%, 5.4%, 3.2%, 1.8%, 1.4%, 0.9%, and 0.9% respectively. It is concluded that rich (AC)(n)(AT)(x)T(y) polymorphisms at the -530 bp region in the BP1 binding site upstream of β-globin gene are found in Chinese Han population. (AC)(2)(AT)(9)T(5), (AC)(2)(AT)(8)T(5), and (AC)(2)(AT)(7)T(7) are 3 major polymorphisms among Chinese Han population, and (AC)(3)(AT)(8)T(5) is a novel polymorphism at the -530 bp region. More studies should be done to explore relation between (AC)(n)(AT)(x)T(y) polymorphisms and β-globin expression.