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Sokkar MF, Hamdy M, Erian PS, Mosaad RM, Elaraby NM, Taher MB, El-Sayed H, Al Komy M, Eid MM, Mohamed AM, Amr KS, El-Kamah GY. Studying the pathogenicity of 26 variants characterized in the first molecular analyses of Egyptian aplastic anemia patients. J Genet Eng Biotechnol 2023; 21:149. [PMID: 38017244 PMCID: PMC10684839 DOI: 10.1186/s43141-023-00585-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/31/2023] [Indexed: 11/30/2023]
Abstract
BACKGROUND 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. METHODS 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. RESULTS 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. CONCLUSIONS 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.
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Affiliation(s)
- Mona F Sokkar
- Molecular Genetics and Enzymology Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt.
| | - Mona Hamdy
- Department of Pediatrics, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Peter Sf Erian
- Human Cytogenetics Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt
| | - Rehab M Mosaad
- Molecular Genetics and Enzymology Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt
| | - Nesma M Elaraby
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt
| | - Mohamed B Taher
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt
| | - Heba El-Sayed
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt
| | - Mohammed Al Komy
- Department of Pediatrics, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Maha M Eid
- Human Cytogenetics Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt
| | - Amal M Mohamed
- Human Cytogenetics Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt
| | - Khalda S Amr
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt
| | - Ghada Y El-Kamah
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre (NRC), Cairo, Egypt
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Shah A, Kumar C, Shanmukhaiah C, Rajendran A, Mudaliar S, Idicula-Thomas S, Vundinti BR. Genomic and computational analysis of four novel variants of MPL gene in Congenital Amegakaryocytic Thrombocytopenia. Ann Hematol 2023; 102:2683-2693. [PMID: 37438490 DOI: 10.1007/s00277-023-05347-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 06/29/2023] [Indexed: 07/14/2023]
Abstract
Congenital amegakaryocytic thrombocytopenia (CAMT) is a rare, genetic, autosomal recessive disorder characterized by severe thrombocytopenia, due to inefficient bone marrow megakaryopoiesis eventually leading to aplasia. Majority of the cases are due to homozygous or compound heterozygous mutations in MPL gene encoding for thrombopoietin (THPO) receptor protein. CAMT can be diagnosed at early phase of life, with major complication of transfusion dependency and hematopoietic transplantation as only curative treatment. We have investigated the sequence variations in MPL gene of 7 bone marrow failure (BMF) subjects, who presented with clinically diverse phenotypes, through next generation sequencing (NGS). Plasma THPO levels were estimated using ELISA. Insilico sequence and structure-based analyses were performed to understand the structural and functional implications of mutations, identified through NGS. We studied 7 CAMT subjects suspected of BMF, who presented with severe thrombocytopenia followed by pancytopenia, bleeding manifestation and physical anomalies. The plasma THPO levels were significantly elevated (p<0.05) in all the cases. Molecular analysis by NGS identified 9 genomic mutations in MPL gene. These included 7 non-synonymous substitution, 1 nonsense substitution and 1 in-del mutations, of which 4 are novel mutations. Insilico analysis predicted damaging effects on THPO-R and its reduced affinity for THPO for all the identified mutations. CAMT is a rare disorder with diverse clinical phenotypes and diagnosis is challenging. The elevated plasma THPO levels should be considered for the primary diagnosis and prognosis of the disease. However, molecular analysis of MPL gene is important for the diagnosis and management of the disease through genetic counselling. Though the cytokines, THPO-R agonist are used for the treatment of CAMT, HSCT is the only curative therapy.
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Affiliation(s)
- Anjali Shah
- Department of Cytogenetics, ICMR-National Institute of Immunohaematology, 13th floor, New Multi-storeyed building, KEM hospital Campus, Parel, Mumbai, Maharashtra, 400012, India
| | - Chandan Kumar
- Biomedical Informatics Centre, ICMR-National Institute for Research in Reproductive and Child Health, Mumbai, Maharashtra, 400012, India
| | - Chandrakala Shanmukhaiah
- Department of Haematology, KEM Hospital, 10th Floor, New Multistoried Building, Parel, Mumbai, Maharashtra, 400012, India
| | - Aruna Rajendran
- Department of Pediatric Hematology, Institute of Child Health and Hospital for Children, Chennai, India
| | | | - Susan Idicula-Thomas
- Biomedical Informatics Centre, ICMR-National Institute for Research in Reproductive and Child Health, Mumbai, Maharashtra, 400012, India
| | - Babu Rao Vundinti
- Department of Cytogenetics, ICMR-National Institute of Immunohaematology, 13th floor, New Multi-storeyed building, KEM hospital Campus, Parel, Mumbai, Maharashtra, 400012, India.
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