Connors L H, Ericsson T, Skare J, Jones L A, Lewis W D, Skinner M
Department of Medicine, Boston University School of Medicine, MA 02118, USA.
Biochim Biophys Acta. 1998 Sep 30;1407(3):185-92. doi: 10.1016/s0925-4439(98)00037-4.
Variant forms of the plasma protein transthyretin (TTR) are associated with the most frequently occurring type of familial systemic amyloidosis. Organ system involvement in transthyretin type amyloidosis (ATTR) is often similar to that which occurs in light chain amyloid disease (AL). The proper diagnosis of ATTR is important since treatment (liver transplantation) differs from that in AL (chemotherapy). We present a two-step test to screen sera for variant TTRs using non-denaturing gel electrophoresis performed in 7.5% acrylamide (PAGE) followed by isoelectric focusing (IEF) between pH 4.0 and 7.0 in 2.5 M urea. Serum samples from 110 patients with amyloidosis and their relatives were tested using this IEF technique and compared to genetic mutation results. Sera from patients with ATTR who underwent liver transplantation were also examined prior to and following surgery. IEF analysis showed the presence of both wild-type and variant TTR in 74 of the 110 serum samples tested. Genomic DNA from peripheral blood was used to identify TTR gene mutations in 77 of the 110 patients. Fifteen variants including Val122Ile, preponderant in the African-American population, could be demonstrated by IEF. The sensitivity of IEF was 96% (74/77) and the specificity was 100% (33/33). The predictive values for a positive or negative result were 100% (74/74) and 92% (33/36), respectively. There were no false-positive results and 4% (3/77) false-negative results. In sera from patients with ATTR who underwent liver transplantation, variant TTR was detected by IEF before, but not after, surgery. A simple, accurate, sensitive method is presented as a useful screening test for variant transthyretins associated with ATTR.
血浆蛋白转甲状腺素蛋白（TTR）的变异形式与最常见的家族性系统性淀粉样变性类型相关。转甲状腺素蛋白型淀粉样变性（ATTR）中的器官系统受累情况通常与轻链淀粉样变性疾病（AL）相似。ATTR的正确诊断很重要，因为其治疗方法（肝移植）与AL（化疗）不同。我们提出了一种两步检测法，使用在7.5%丙烯酰胺中进行的非变性凝胶电泳（PAGE），随后在2.5M尿素中于pH 4.0至7.0之间进行等电聚焦（IEF），以筛查血清中的变异TTR。使用这种IEF技术对110例淀粉样变性患者及其亲属的血清样本进行检测，并与基因突变结果进行比较。对接受肝移植的ATTR患者的血清在手术前后也进行了检查。IEF分析显示，在检测的110份血清样本中的74份中同时存在野生型和变异型TTR。使用外周血的基因组DNA对110例患者中的77例进行TTR基因突变鉴定。包括在非裔美国人中占优势的Val122Ile在内的15种变异可通过IEF检测到。IEF的敏感性为96%（74/77），特异性为100%（33/33）。阳性或阴性结果的预测值分别为100%（74/74）和92%（33/36）。没有假阳性结果，假阴性结果为4%（3/77）。在接受肝移植的ATTR患者的血清中，术前通过IEF检测到变异TTR，但术后未检测到。本文介绍了一种简单、准确、灵敏的方法，作为与ATTR相关的变异转甲状腺素蛋白的有用筛查试验。
