Marrone Anna, Sokhal Priya, Walne Amanda, Beswick Richard, Kirwan Michael, Killick Sally, Williams Mike, Marsh Judith, Vulliamy Tom, Dokal Inderjeet
Academic Unit of Paediatrics, Institute of Cell and Molecular Science, Barts and The London,Queen Mary's School of Medicine and Dentistry, The Blizard Building, 4 Newark Street, London, E1 2AT, UK.
Haematologica. 2007 Aug;92(8):1013-20. doi: 10.3324/haematol.11407. Epub 2007 Jul 20.
Functional characterization of heterozygous TERC (telomerase RNA component) and TERT (telomerase reverse transcriptase) mutations found in autosomal dominant dyskeratosis congenita (DC) and aplastic anemia (AA) shows that telomerase function is defective and that this is associated with short telomeres. This leads to reduced cell longevity with maximal impact on tissues with high proliferate potential. The aim of this study was to establish the role of TERC in the pathophysiology of uncharacterized patients with AA with some features of DC.
The TERC gene was screened for mutations by denaturing high performance liquid chromatography. To determine the functional significance of TERC mutations telomerase activity was assessed in an in vitro (TRAP) assay and telomere length of patients' samples was determined using Southern blot analysis. RESULTS This study led to the identification of four novel TERC mutations (G178A, C180T, D52-86 and G2C) and a recurrent TERC mutation (D110-113GACT).
Two of the de novo TERC mutations (G178A and C180T) found uniquely produce a clinical phenotype in the first generation, differing from previously published cases in which individuals in the first generation are usually asymptomatic. Curiously these mutations are located near the triple-helix domain of TERC. We also observed that the recurrent D110-113GACT can present with AA, myelodysplasia or leukemia. The D52-86 is associated with varied phenotypes including pulmonary disease (pulmonary fibrosis) as the first presentation. In summary, this study reports the functional characterization of several novel TERC mutations associated with varied hematologic and extra-hematologic presentations.
在常染色体显性遗传性先天性角化不良（DC）和再生障碍性贫血（AA）中发现的杂合性TERC（端粒酶RNA组分）和TERT（端粒酶逆转录酶）突变的功能特征表明，端粒酶功能存在缺陷，且这与短端粒相关。这导致细胞寿命缩短，对具有高增殖潜能的组织影响最大。本研究的目的是确定TERC在具有DC某些特征的未明确诊断的AA患者病理生理学中的作用。
通过变性高效液相色谱法筛查TERC基因的突变。为确定TERC突变的功能意义，在体外（TRAP）试验中评估端粒酶活性，并使用Southern印迹分析确定患者样本的端粒长度。结果：本研究鉴定出四个新的TERC突变（G178A、C180T、D52 - 86和G2C）以及一个复发性TERC突变（D110 - 113GACT）。
新发现的两个TERC突变（G178A和C180T）在第一代中独特地产生了临床表型，这与先前发表的病例不同，在先前的病例中第一代个体通常无症状。奇怪的是，这些突变位于TERC的三螺旋结构域附近。我们还观察到复发性D110 - 113GACT可表现为AA、骨髓增生异常或白血病。D52 - 86与多种表型相关，包括以肺部疾病（肺纤维化）为首发表现。总之，本研究报告了与多种血液学和血液外表现相关的几种新的TERC突变的功能特征。
