Novel ACTN1 variants in cases of thrombocytopenia
Anne Vincenot, Paul Saultier, Shinji Kunishima, Marjorie Poggi, Marie-Françoise Hurtaud-Roux, Alain Roussel, Actn Study Coinvestigators, Nicole Schlegel, Marie-Christine Alessi, Anne Vincenot, Paul Saultier, Shinji Kunishima, Marjorie Poggi, Marie-Françoise Hurtaud-Roux, Alain Roussel, Actn Study Coinvestigators, Nicole Schlegel, Marie-Christine Alessi
Abstract
The ACTN1 gene has been implicated in inherited macrothrombocytopenia. To decipher the spectrum of variants and phenotype of ACTN1-related thrombocytopenia, we sequenced the ACTN1 gene in 272 cases of unexplained chronic or familial thrombocytopenia. We identified 15 rare, monoallelic, nonsynonymous and likely pathogenic ACTN1 variants in 20 index cases from 20 unrelated families. Thirty-one family members exhibited thrombocytopenia. Targeted sequencing was carried out on 12 affected relatives, which confirmed presence of the variant. Twenty-eight of 32 cases with monoallelic ACTN1 variants had mild to no bleeding complications. Eleven cases harbored 11 different unreported ACTN1 variants that were monoallelic and likely pathogenic. Nine variants were located in the α-actinin-1 (ACTN1) rod domain and were predicted to hinder dimer formation. These variants displayed a smaller increase in platelet size compared with variants located outside the rod domain. In vitro expression of the new ACTN1 variants induced actin network disorganization and led to increased thickness of actin fibers. These findings expand the repertoire of ACTN1 variants associated with thrombocytopenia and highlight the high frequency of ACTN1-related thrombocytopenia cases. The rod domain, like other ACTN1 functional domains, may be mutated resulting in actin disorganization in vitro and thrombocytopenia with normal platelet size in most cases.
Keywords: ACTN1; actin; actinin; constitutional; platelet; rod domain; thrombocytopenia.
Conflict of interest statement
The authors declare that there are no conflict of interests.
© 2019 The Authors. Human Mutation Published by Wiley Periodicals, Inc.
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References
- Bottega, R. , Marconi, C. , Faleschini, M. , Baj, G. , Cagioni, C. , Pecci, A. , … Noris, P. (2015). ACTN1‐related thrombocytopenia: Identification of novel families for phenotypic characterization. Blood, 125(5), 869–872. 10.1182/blood-2014-08-594531
- Boutroux, H. , David, B. , Guéguen, P. , Frange, P. , Vincenot, A. , Leverger, G. , & Favier, R. (2017). ACTN1‐related Macrothrombocytopenia: A novel entity in the progressing field of pediatric thrombocytopenia. Journal of Pediatric Hematology/Oncology, 39(8), e515–e518. 10.1097/MPH.0000000000000885
- Burkhart, J. M. , Vaudel, M. , Gambaryan, S. , Radau, S. , Walter, U. , Martens, L. , … Zahedi, R. P. (2012). The first comprehensive and quantitative analysis of human platelet protein composition allows the comparative analysis of structural and functional pathways. Blood, 120(15), e73–e82. 10.1182/blood-2012-04-416594
- Chakravarty, D. , Chakraborti, S. , & Chakrabarti, P. (2015). Flexibility in the N‐terminal actin‐binding domain: Clues from in silico mutations and molecular dynamics. Proteins, 83(4), 696–710. 10.1002/prot.24767
- Djinovic‐Carugo, K. , Gautel, M. , Ylänne, J. , & Young, P. (2002). The spectrin repeat: A structural platform for cytoskeletal protein assemblies. FEBS Letters, 513(1), 119–123.
- Faleschini, M. , Melazzini, F. , Marconi, C. , Giangregorio, T. , Pippucci, T. , Cigalini, E. , … Noris, P. (2018). ACTN1 mutations lead to a benign form of platelet macrocytosis not always associated with thrombocytopenia. British Journal of Haematology, 183(2), 276–288. 10.1111/bjh.15531
- Fatkin, D. , MacRae, C. , Sasaki, T. , Wolff, M. R. , Porcu, M. , Frenneaux, M. , … McDonough, B. (1999). Missense mutations in the rod domain of the lamin A/C gene as causes of dilated cardiomyopathy and conduction‐system disease. The New England Journal of Medicine, 341(23), 1715–1724. 10.1056/NEJM199912023412302
- Foley, K. S. , & Young, P. W. (2013). An analysis of splicing, actin‐binding properties, heterodimerization and molecular interactions of the non‐muscle α‐actinins. The Biochemical Journal, 452(3), 477–488. 10.1042/BJ20121824
- Gache, Y. , Landon, F. , & Olomucki, A. (1984). Polymorphism of alpha‐actinin from human blood platelets. Homodimeric and heterodimeric forms. European Journal of Biochemistry, 141(1), 57–61.
- Gimona, M. , & Mital, R. (1998). The single CH domain of calponin is neither sufficient nor necessary for F‐actin binding. Journal of Cell Science, 111(Pt 13), 1813–1821.
- Golji, J. , Collins, R. , & Mofrad, M. R. K. (2009). Molecular mechanics of the alpha‐actinin rod domain: Bending, torsional, and extensional behavior. PLoS Computational Biology, 5(5), e1000389 10.1371/journal.pcbi.1000389
- Guéguen, P. , Rouault, K. , Chen, J.‐M. , Raguénès, O. , Fichou, Y. , Hardy, E. , … Férec, C. (2013). A missense mutation in the alpha‐actinin 1 gene (ACTN1) is the cause of autosomal dominant macrothrombocytopenia in a large French family. PLoS One, 8(9), e74728 10.1371/journal.pone.0074728
- Kaplan, J. M. , Kim, S. H. , North, K. N. , Rennke, H. , Correia, L. A. , Tong, H. Q. , … Pollak, M. R. (2000). Mutations in ACTN4, encoding alpha‐actinin‐4, cause familial focal segmental glomerulosclerosis. Nature Genetics, 24(3), 251–256. 10.1038/73456.
- Kircher, M. , Witten, D. M. , Jain, P. , O'Roak, B. J. , Cooper, G. M. , & Shendure, J. (2014). A general framework for estimating the relative pathogenicity of human genetic variants. Nature Genetics, 46(3), 310–315. 10.1038/ng.2892
- Kos, C. H. , Le, T. C. , Sinha, S. , Henderson, J. M. , Kim, S. H. , Sugimoto, H. , … Pollak, M. R. (2003). Mice deficient in alpha‐actinin‐4 have severe glomerular disease. The Journal of Clinical Investigation, 111(11), 1683–1690. 10.1172/JCI17988
- Kunishima, S. , Okuno, Y. , Yoshida, K. , Shiraishi, Y. , Sanada, M. , Muramatsu, H. , … Ogawa, S. (2013). ACTN1 mutations cause congenital macrothrombocytopenia. American Journal of Human Genetics, 92(3), 431–438. 10.1016/j.ajhg.2013.01.015
- Murphy, A. C. H. , Lindsay, A. J. , McCaffrey, M. W. , Djinović‐Carugo, K. , & Young, P. W. (2016). Congenital macrothrombocytopenia‐linked mutations in the actin‐binding domain of α‐actinin‐1 enhance F‐actin association. FEBS Letters, 590(6), 685–695. 10.1002/1873-3468.12101
- Nurden, A. T. , Freson, K. , & Seligsohn, U. (2012). Inherited platelet disorders. Haemophilia, 18(Suppl 4), 154–160. 10.1111/j.1365-2516.2012.02856.x
- Ribeiro, E. , Pinotsis, N. , Ghisleni, A. , Salmazo, A. , Konarev, P. , Kostan, J. , … Djinović‐Carugo, K. (2014). The structure and regulation of human muscle α‐actinin. Cell, 159(6), 1447–1460. 10.1016/j.cell.2014.10.056
- Richards, S. , Aziz, N. , Bale, S. , Bick, D. , Das, S. , Gastier‐Foster, J. , … ACMG Laboratory Quality Assurance Committee (2015). Standards and guidelines for the interpretation of sequence variants: A joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genetics in Medicine, 17(5), 405–424. 10.1038/gim.2015.30
- Saposnik, B. , Binard, S. , Fenneteau, O. , Nurden, A. , Nurden, P. , Hurtaud‐Roux, M.‐F. , … French MYH9 networka (2014). Mutation spectrum and genotype‐phenotype correlations in a large French cohort of MYH9‐Related Disorders. Molecular Genetics and Genomic Medicine, 2(4), 297–312. 10.1002/mgg3.68
- Saultier, P. , Vidal, L. , Canault, M. , Bernot, D. , Falaise, C. , Pouymayou, C. , … Alessi, M.‐C. (2017). Macrothrombocytopenia and dense granule deficiency associated with FLI1 variants: Ultrastructural and pathogenic features. Haematologica, 102(6), 1006–1016. 10.3324/haematol.2016.153577
- Sjöblom, B. , Salmazo, A. , & Djinović‐Carugo, K. (2008). Alpha‐actinin structure and regulation. Cellular and Molecular Life Sciences, 65(17), 2688–2701. 10.1007/s00018-008-8080-8
- Westbury, S. K. , Shoemark, D. K. , & Mumford, A. D. (2017). ACTN1 variants associated with thrombocytopenia. Platelets, 28(6), 625–627. 10.1080/09537104.2017.1356455
- Westbury, S. K. , Turro, E. , Greene, D. , Lentaigne, C. , Kelly, A. M. , Bariana, T. K. , … BRIDGE‐BPD Consortium (2015). Human phenotype ontology annotation and cluster analysis to unravel genetic defects in 707 cases with unexplained bleeding and platelet disorders. Genome Medicine, 7(1), 36 10.1186/s13073-015-0151-5
- Yasutomi, M. , Kunishima, S. , Okazaki, S. , Tanizawa, A. , Tsuchida, S. , & Ohshima, Y. (2016). ACTN1 rod domain mutation associated with congenital macrothrombocytopenia. Annals of Hematology, 95(1), 141–144. 10.1007/s00277-015-2517-6
Source: PubMed