Sokkar Mona F, Hamdy Mona, Erian Peter Sf, Mosaad Rehab M, Elaraby Nesma M, Taher Mohamed B, El-Sayed Heba, Al Komy Mohammed, Eid Maha M, Mohamed Amal M, Amr Khalda S, El-Kamah Ghada Y
Molecular Genetics and Enzymology Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt.
Department of Pediatrics, Faculty of Medicine, Cairo University, Cairo, Egypt.
J Genet Eng Biotechnol. 2023 Nov 29;21(1):149. doi: 10.1186/s43141-023-00585-8.
Aplastic anemia (AA) is a bone marrow disorder characterized by peripheral pancytopenia and marrow hypoplasia which can lead to life-threatening complications. Our objective was to study the telomerase genes (TERT and TERC) variants, explore their relationship to telomere shortening and TERT gene expression, and to identify variants in the MPL gene within Egyptian AA patients.
Forty AA patients and 40 sex- and age-matched healthy individuals as the control group were studied through sequencing of TERT, TERC, and MPL genes. Quantitative real-time PCR (qRT-PCR) was used for measuring TERT gene expression. Telomere length (TL) was measured using the Quantitative Fluorescence In Situ Hybridization (Q-FISH) technique. In silico analysis was performed for the prediction of the pathogenicity of resultant variants.
Sequencing of MPL, TERT, and TERC genes identified 26 variants. Eleven variants were identified in the MPL gene. Three of them are pathogenic: two missense [c.305 G>A, c.1589 C>T] and one splice site [g.9130T>G]. TERT gene sequencing showed thirteen variants, among them, four novel [c.484G>A, c.499G>A, c.512G>A, c.3164C>G] and two previously reported [c.835G>A, c.2031C>T] were predicted to be pathogenic. Two variants were characterized within the TERC gene; n.514A>G and n.463 C>T. TERT gene expression was downregulated in 70% of studied patients and the Q-FISH technique detected telomere shortening in 82.5% of patients.
Twenty-six pathogenic and benign variants within the TERC, TERT, and MPL genes were identified among the studied AA patients that were in several cases associated with shortened telomeres and/or lower TERT gene expression. Genotype/phenotype correlation in AA patients is of great importance in explaining the disease severity and guiding therapeutic decisions.
再生障碍性贫血（AA）是一种骨髓疾病，其特征为外周血全血细胞减少和骨髓发育不全，可导致危及生命的并发症。我们的目的是研究端粒酶基因（TERT和TERC）变异，探讨它们与端粒缩短和TERT基因表达的关系，并鉴定埃及AA患者中MPL基因的变异。
通过对TERT、TERC和MPL基因进行测序，研究了40例AA患者和40例性别和年龄匹配的健康个体作为对照组。采用定量实时PCR（qRT-PCR）测量TERT基因表达。使用定量荧光原位杂交（Q-FISH）技术测量端粒长度（TL）。对所得变异的致病性进行了计算机分析预测。
MPL、TERT和TERC基因测序鉴定出26个变异。在MPL基因中鉴定出11个变异。其中3个是致病性的：2个错义变异[c.305 G>A，c.1589 C>T]和1个剪接位点变异[g.9130T>G]。TERT基因测序显示13个变异，其中4个新变异[c.484G>A，c.499G>A，c.512G>A，c.3164C>G]和2个先前报道的变异[c.835G>A，c.2031C>T]被预测为致病性变异。在TERC基因中鉴定出2个变异；n.514A>G和n.463 C>T。70%的研究患者TERT基因表达下调，Q-FISH技术检测到82.5%的患者端粒缩短。
在所研究的AA患者中，TERC、TERT和MPL基因中鉴定出26个致病性和良性变异，其中一些病例与端粒缩短和/或TERT基因表达降低有关。AA患者的基因型/表型相关性对于解释疾病严重程度和指导治疗决策非常重要。
