Ehmer Ursula, Lankisch Tim O, Erichsen Thomas J, Kalthoff Sandra, Freiberg Nicole, Wehmeier Michael, Manns Michael P, Strassburg Christian P
Department of Gastroenterology, Hepatology and Endocrinology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
J Mol Diagn. 2008 Nov;10(6):549-52. doi: 10.2353/jmoldx.2008.080036. Epub 2008 Oct 2.
Gilbert's syndrome causes mild, unconjugated hyperbilirubinemia and is present in approximately 10% of the Caucasian population. The basis of the disorder is a 70% reduction in bilirubin glucuronidation catalyzed by the UDP-glucuronosyltransferase 1A1 (UGT1A1), which, in Caucasians, is the result of a homozygous TA insertion into the promoter region of the UGT1A1 gene (UGT1A128). Homozygous carriers of UGT1A128 as well as those with additional UGT1A variants can suffer from severe irinotecan toxicity or jaundice during treatment with the protease inhibitor atazanavir. UGT1A128 genotyping identifies patients at risk for drug toxicity and can increase drug safety by dose individualization. Rapid and facile UGT1A128 genotyping is therefore of great clinical importance. Two hundred ninety-one patients with suspected Gilbert's syndrome were genotyped using the TaqMan 5'nuclease assay with minor groove binder-non fluorescent quench probes; results were confirmed by direct sequencing. Ninety-six patients (33%) were homozygous for UGT1A128, which was verified by direct sequencing of a different PCR product showing 100% concordance with the TaqMan PCR results. We describe a novel UGT1A128 genotyping method that employs allelic discrimination by TaqMan PCR. This assay provides a rapid, high-throughput, and cost-effective method for Gilbert's syndrome genotyping, which is of value for pretreatment screening of potential irinotecan toxicity. The method utilizes a technological platform that is widely used in clinical practice and could therefore be easily adapted for routine clinical applications.
吉尔伯特综合征可导致轻度非结合性高胆红素血症，约10%的白种人患有该综合征。该疾病的基础是由尿苷二磷酸葡萄糖醛酸基转移酶1A1（UGT1A1）催化的胆红素葡萄糖醛酸化反应降低了70%，在白种人中，这是由于UGT1A1基因（UGT1A128）启动子区域纯合性TA插入所致。UGT1A128的纯合携带者以及具有其他UGT1A变体的人在使用蛋白酶抑制剂阿扎那韦治疗期间可能会出现严重的伊立替康毒性或黄疸。UGT1A128基因分型可识别有药物毒性风险的患者，并可通过个体化给药提高用药安全性。因此，快速简便的UGT1A128基因分型具有重要的临床意义。使用带有小沟结合剂-非荧光猝灭探针的TaqMan 5'核酸酶分析法对291例疑似吉尔伯特综合征的患者进行基因分型；结果通过直接测序得以证实。96例患者（33%）为UGT1A128纯合子，通过对不同PCR产物的直接测序验证，结果与TaqMan PCR结果100%一致。我们描述了一种通过TaqMan PCR进行等位基因鉴别来对UGT1A128进行基因分型的新方法。该分析方法为吉尔伯特综合征基因分型提供了一种快速、高通量且经济高效的方法，对于伊立替康潜在毒性的预处理筛查具有重要价值。该方法利用了临床实践中广泛使用的技术平台，因此可以很容易地应用于常规临床检测。
