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Journal of Zhejiang University SCIENCE B
ISSN 1673-1581(Print), 1862-1783(Online), Monthly
2014 Vol.15 No.5 P.474-481
Two unrelated patients with rare Crigler-Najjar syndrome type I: two novel mutations and a patient with loss of heterozygosity of UGT1A1 gene
Abstract: Crigler-Najjar syndrome type I (CN-I) is the most severe type of hereditary unconjugated hyperbilirubinemia. It is caused by homozygous or compound heterozygous mutations of the UDP-glycuronosyltransferase gene (UGT1A1) on chromosome 2q37. Two patients clinically diagnosed with CN-I were examined in this paper. We sequenced five exons and their flanking sequences, specifically the promoter region of UGT1A1, of the two patients and their parents. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the UGT1A1 gene copy number of one patient. In patient A, two mutations, c.239_245delCTGTGCC (p.Pro80HisfsX6; had not been reported previously) and c.1156G>T (p.Val386Phe), were identified. In patient B, we found that this patient had lost heterozygosity of the UGT1A1 gene by inheriting a deletion of one allele, and had a novel mutation c.1253delT (p.Met418ArgfsX5) in the other allele. In summary, we detected three UGT1A1 mutations in two CN-I patients: c.239_245delCTGTGCC (p.Pro80HisfsX6), c.1253delT (p.Met418ArgfsX5), and c.1156G>T (p.Val386Phe). The former two mutations are pathogenic; however, the pathogenic mechanism of c.1156G>T (p.Val386Phe) is unknown.
Key words: Crigler-Najjar syndrome type I (CN-I), Hyperbilirubinemia, UDP-glycuronosyltransferase gene (UGT1A1), Mutation, Loss of heterozygosity
研究方法:经知情同意后,采集两例患儿及父母外周血;聚合酶链式反应(PCR)扩增UGT1A1基因5个外显子及外显子-内含子交界处,进行测序分析。应用实时定量PCR(qRT-PCR)测定其中一例患者UGT1A1基因的拷贝数。
重要结论:本研究在两例CN-I型患儿中检测到3个UGT1A1基因突变:c.239_245delCTGTGCC (p.Pro80HisfsX6)、c.1253delT (p.Met418ArgfsX5)和c.1156G>T (p.Val386Phe)。前两个突变均为新发的移码突变,预测提前出现终止密码或诱发RNA降解;而突变c.1156G>T (p.Val386Phe)的致病机制尚需进一步研究。
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DOI:
10.1631/jzus.B1300233
CLC number:
R722
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On-line Access:
2014-05-05
Received:
2013-09-01
Revision Accepted:
2014-02-09
Crosschecked:
2014-04-16