1
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Jaspersen SL, Stacy AV, McGlynn MC, Gooch CF, Wilson DB, Bolton KL. Phenotypic heterogeneity associated with a novel MECOM variant: Mild thrombocytopenia to hydrops fetalis. Pediatr Blood Cancer 2024; 71:e30991. [PMID: 38602302 DOI: 10.1002/pbc.30991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 04/12/2024]
Affiliation(s)
- Sue L Jaspersen
- Department of Pediatrics, Division of Hematology and Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Andrea V Stacy
- Department of Pediatrics, Division of Hematology and Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Mary Claire McGlynn
- Department of Pediatrics, Division of Hematology and Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Catherine F Gooch
- Department of Pediatrics, Division of Genetics and Genomic Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - David B Wilson
- Department of Pediatrics, Division of Hematology and Oncology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kelly L Bolton
- John T. Milliken Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
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2
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Huang D, Jiang M, Zhu Y, Li D, Lu X, Gao J. A novel missense mutation in the MECOM gene in a Chinese boy with radioulnar synostosis with amegakaryocytic thrombocytopenia. BMC Pediatr 2024; 24:62. [PMID: 38245683 PMCID: PMC10799460 DOI: 10.1186/s12887-024-04552-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 01/11/2024] [Indexed: 01/22/2024] Open
Abstract
Radioulnar synostosis with amegakaryocytic thrombocytopenia (RUSAT) type 2, caused by MDS1 and EVI1 complex locus (MECOM) gene mutations, is a rare inherited bone marrow failure syndrome (IBMFS) with skeletal anomalies, characterized by varying presentation of congenital thrombocytopenia (progressing to pancytopenia), bilateral proximal radioulnar synostosis, and other skeletal abnormalities. Due to limited knowledge and heterogenous manifestations, clinical diagnosis of the disease is challenging. Here we reported a novel MECOM mutation in a Chinese boy with typical clinical features for RUSAT-2. Trio-based whole exome sequencing of buccal swab revealed a novel heterozygous missense mutation in exon 11 of the MECOM gene (chr3:168818673; NM_001105078.3:c.2285G > A). The results strongly suggest that the variant was a germline mutation and disease-causing mutation. The patient received matched unrelated donor hematopoetic stem cell transplantation (HSCT). This finding was not only expanded the pathogenic mutation spectrum of MECOM gene, but also provided key information for clinical diagnosis and treatment of RUSAT-2.
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Affiliation(s)
- Duowen Huang
- Department of Pediatric Hematology and Oncology, West China Second University Hospital, Sichuan University, No. 20 Section 3, South Renmin Road, Chengdu, 610041, Sichuan Province, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, 610041, Sichuan Province, China
| | - Mingyan Jiang
- Department of Pediatric Hematology and Oncology, West China Second University Hospital, Sichuan University, No. 20 Section 3, South Renmin Road, Chengdu, 610041, Sichuan Province, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, 610041, Sichuan Province, China
| | - Yiping Zhu
- Department of Pediatric Hematology and Oncology, West China Second University Hospital, Sichuan University, No. 20 Section 3, South Renmin Road, Chengdu, 610041, Sichuan Province, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, 610041, Sichuan Province, China
| | - Dongjun Li
- Department of Pediatric Hematology and Oncology, West China Second University Hospital, Sichuan University, No. 20 Section 3, South Renmin Road, Chengdu, 610041, Sichuan Province, China
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, 610041, Sichuan Province, China
| | - Xiaoxi Lu
- Department of Pediatric Hematology and Oncology, West China Second University Hospital, Sichuan University, No. 20 Section 3, South Renmin Road, Chengdu, 610041, Sichuan Province, China.
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, 610041, Sichuan Province, China.
| | - Ju Gao
- Department of Pediatric Hematology and Oncology, West China Second University Hospital, Sichuan University, No. 20 Section 3, South Renmin Road, Chengdu, 610041, Sichuan Province, China.
- Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University), Ministry of Education, Chengdu, 610041, Sichuan Province, China.
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3
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Ammeti D, Marzollo A, Gabelli M, Zanchetta ME, Tretti-Parenzan C, Bottega R, Capaci V, Biffi A, Savoia A, Bresolin S, Faleschini M. A novel mutation in MECOM affects MPL regulation in vitro and results in thrombocytopenia and bone marrow failure. Br J Haematol 2023; 203:852-859. [PMID: 37610030 DOI: 10.1111/bjh.19023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/21/2023] [Accepted: 07/21/2023] [Indexed: 08/24/2023]
Abstract
MECOM-associated syndrome (MECOM-AS) is a rare disease characterized by amegakaryocytic thrombocytopenia, progressive bone marrow failure, pancytopenia and radioulnar synostosis with high penetrance. The clinical phenotype may also include finger malformations, cardiac and renal alterations, hearing loss, B-cell deficiency and predisposition to infections. The syndrome, usually diagnosed in the neonatal period because of severe thrombocytopenia, is caused by mutations in the MECOM gene, encoding for the transcription factor EVI1. The mechanism linking the alteration of EVI1 function and thrombocytopenia is poorly understood. In a paediatric patient affected by severe thrombocytopenia, we identified a novel variant of the MECOM gene (p.P634L), whose effect was tested on pAP-1 enhancer element and promoters of targeted genes showing that the mutation impairs the repressive activity of the transcription factor. Moreover, we demonstrated that EVI1 controls the transcriptional regulation of MPL, a gene whose mutations are responsible for congenital amegakaryocytic thrombocytopenia (CAMT), potentially explaining the partial overlap between MECOM-AS and CAMT.
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Affiliation(s)
- Daniele Ammeti
- Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy
| | - Antonio Marzollo
- Pediatric Hematology, Oncology and Stem Cell Transplant Division, Padua University Hospital, Padua, Italy
| | - Maria Gabelli
- Pediatric Hematology, Oncology and Stem Cell Transplant Division, Padua University Hospital, Padua, Italy
- Maternal and Child Health Department, Padua University, Padua, Italy
| | | | - Caterina Tretti-Parenzan
- Pediatric Hematology, Oncology and Stem Cell Transplant Division, Padua University Hospital, Padua, Italy
- Maternal and Child Health Department, Padua University, Padua, Italy
| | - Roberta Bottega
- Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy
| | - Valeria Capaci
- Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy
| | - Alessandra Biffi
- Pediatric Hematology, Oncology and Stem Cell Transplant Division, Padua University Hospital, Padua, Italy
- Maternal and Child Health Department, Padua University, Padua, Italy
| | - Anna Savoia
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - Silvia Bresolin
- Pediatric Hematology, Oncology and Stem Cell Transplant Division, Padua University Hospital, Padua, Italy
- Maternal and Child Health Department, Padua University, Padua, Italy
| | - Michela Faleschini
- Institute for Maternal and Child Health, IRCCS Burlo Garofolo, Trieste, Italy
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4
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Nagai K, Niihori T, Muto A, Hayashi Y, Abe T, Igarashi K, Aoki Y. Mecom mutation related to radioulnar synostosis with amegakaryocytic thrombocytopenia reduces HSPCs in mice. Blood Adv 2023; 7:5409-5420. [PMID: 37099686 PMCID: PMC10509669 DOI: 10.1182/bloodadvances.2022008462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 04/20/2023] [Accepted: 04/23/2023] [Indexed: 04/28/2023] Open
Abstract
Radioulnar synostosis with amegakaryocytic thrombocytopenia (RUSAT) is an inherited bone marrow failure syndrome characterized by the congenital fusion of the forearm bones. RUSAT is largely caused by missense mutations that are clustered in a specific region of the MDS1 and EVI1 complex locus (MECOM). EVI1, a transcript variant encoded by MECOM, is a zinc finger transcription factor involved in hematopoietic stem cell maintenance that induce leukemic transformation when overexpressed. Mice with exonic deletions in Mecom show reduced hematopoietic stem and progenitor cells (HSPCs). However, the pathogenic roles of RUSAT-associated MECOM mutations in vivo have not yet been elucidated. To investigate the impact of the RUSAT-associated MECOM mutation on the phenotype, we generated knockin mice harboring a point mutation (translated into EVI1 p.H752R and MDS1-EVI1 p.H942R), which corresponds to an EVI1 p.H751R and MDS1-EVI1 p.H939R mutation identified in a patient with RUSAT. Homozygous mutant mice died at embryonic day 10.5 to 11.5. Heterozygous mutant mice (Evi1KI/+ mice) grew normally without radioulnar synostosis. Male Evi1KI/+ mice, aged between 5 and 15 weeks, exhibited lower body weight, and those aged ≥16 weeks showed low platelet counts. Flow cytometric analysis of bone marrow cells revealed a decrease in HSPCs in Evi1KI/+ mice between 8 and 12 weeks. Moreover, Evi1KI/+ mice showed delayed leukocyte and platelet recovery after 5-fluorouracil-induced myelosuppression. These findings suggest that Evi1KI/+ mice recapitulate the bone marrow dysfunction in RUSAT, similar to that caused by loss-of-function Mecom alleles.
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Affiliation(s)
- Koki Nagai
- Department of Medical Genetics, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Tetsuya Niihori
- Department of Medical Genetics, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Akihiko Muto
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yoshikazu Hayashi
- Division of Functional Structure, Department of Morphological Biology, Fukuoka Dental College, Fukuoka, Japan
| | - Taiki Abe
- Department of Medical Genetics, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kazuhiko Igarashi
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yoko Aoki
- Department of Medical Genetics, Tohoku University Graduate School of Medicine, Sendai, Japan
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5
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Voit RA, Sankaran VG. MECOM Deficiency: from Bone Marrow Failure to Impaired B-Cell Development. J Clin Immunol 2023:10.1007/s10875-023-01545-0. [PMID: 37407873 DOI: 10.1007/s10875-023-01545-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 06/26/2023] [Indexed: 07/07/2023]
Abstract
MECOM deficiency is a recently identified inborn error of immunity and inherited bone marrow failure syndrome caused by haploinsufficiency of the hematopoietic transcription factor MECOM. It is unique among inherited bone marrow failure syndromes, many of which present during later childhood or adolescence, because of the early age of onset and severity of the pancytopenia, emphasizing the importance and gene dose dependency of MECOM during hematopoiesis. B-cell lymphopenia and hypogammaglobulinemia have been described in a subset of patients with MECOM deficiency. While the mechanisms underlying the B-cell deficiency are currently unknown, recent work has provided mechanistic insights into the function of MECOM in hematopoietic stem cell (HSC) maintenance. MECOM binds to regulatory enhancers that control the expression of a network of genes essential for HSC maintenance and self-renewal. Heterozygous mutations, as seen in MECOM-deficient bone marrow failure, lead to dysregulated MECOM network expression. Extra-hematopoietic manifestations of MECOM deficiency, including renal and cardiac anomalies, radioulnar synostosis, clinodactyly, and hearing loss, have been reported. Individuals with specific genotypes have some of the systemic manifestations with isolated mild thrombocytopenia or without hematologic abnormalities, highlighting the tissue specificity of mutations in some MECOM domains. Those infants with MECOM-associated bone marrow failure require HSC transplantation for survival. Here, we review the expanding cohort of patient phenotypes and accompanying genotypes resulting in MECOM deficiency, and the proposed mechanisms underlying MECOM regulation of human HSC maintenance and B-cell development.
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Affiliation(s)
- Richard A Voit
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02115, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Vijay G Sankaran
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02115, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
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6
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Lozano Chinga MM, Bertuch AA, Afify Z, Dollerschell K, Hsu JI, John TD, Rao ES, Rowe RG, Sankaran VG, Shimamura A, Williams DA, Nakano TA. Expanded phenotypic and hematologic abnormalities beyond bone marrow failure in MECOM-associated syndromes. Am J Med Genet A 2023; 191:1826-1835. [PMID: 37067177 PMCID: PMC10330190 DOI: 10.1002/ajmg.a.63208] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 02/17/2023] [Accepted: 03/31/2023] [Indexed: 04/18/2023]
Abstract
The MECOM gene encodes multiple protein isoforms that are essential for hematopoietic stem cell self-renewal and maintenance. Germline MECOM variants have been associated with congenital thrombocytopenia, radioulnar synostosis and bone marrow failure; however, the phenotypic spectrum of MECOM-associated syndromes continues to expand and novel pathogenic variants continue to be identified. We describe eight unrelated patients who add to the previously known phenotypes and genetic defects of MECOM-associated syndromes. As each subject presented with unique MECOM variants, the series failed to demonstrate clear genotype-to-phenotype correlation but may suggest a role for additional modifiers that affect gene expression and subsequent phenotype. Recognition of the expanded hematologic and non-hematologic clinical features allows for rapid molecular diagnosis, early identification of life-threatening complications, and improved genetic counseling for families. A centralized international publicly accessible database to share annotated MECOM variants would advance their clinical interpretation and provide a foundation to perform functional MECOM studies.
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Affiliation(s)
- Michell M Lozano Chinga
- Primary Children's Hospital, University of Utah, Salt Lake City, Utah, USA
- University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | - Alison A Bertuch
- Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA
| | - Zeinab Afify
- Primary Children's Hospital, University of Utah, Salt Lake City, Utah, USA
| | - Kaylee Dollerschell
- Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Joanne I Hsu
- Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA
| | - Tami D John
- Baylor College of Medicine and Texas Children's Hospital, Houston, Texas, USA
| | - Emily S Rao
- Johns Hopkins Hospital, Baltimore, Maryland, USA
| | - Robert Grant Rowe
- Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Vijay G Sankaran
- Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Akiko Shimamura
- Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston Children's Hospital, Boston, Massachusetts, USA
| | - David A Williams
- Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Taizo A Nakano
- Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, Colorado, USA
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7
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Irie M, Niihori T, Nakano T, Suzuki T, Katayama S, Moriya K, Niizuma H, Suzuki N, Saito-Nanjo Y, Onuma M, Rikiishi T, Sato A, Hangai M, Hiwatari M, Ikeda J, Tanoshima R, Shiba N, Yuza Y, Yamamoto N, Hashii Y, Kato M, Takita J, Maeda M, Aoki Y, Imaizumi M, Sasahara Y. Reduced-intensity conditioning is effective for allogeneic hematopoietic stem cell transplantation in infants with MECOM-associated syndrome. Int J Hematol 2022; 117:598-606. [PMID: 36515795 PMCID: PMC10063491 DOI: 10.1007/s12185-022-03505-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 12/01/2022] [Accepted: 12/01/2022] [Indexed: 12/15/2022]
Abstract
Mutations in the MECOM encoding EVI1 are observed in infants who have radioulnar synostosis with amegakaryocytic thrombocytopenia. MECOM-associated syndrome was proposed based on clinical heterogeneity. Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for progressive bone marrow failure. However, data regarding allogeneic HSCT for this rare disease are limited. We retrospectively assessed overall survival, conditioning regimen, regimen-related toxicities and long-term sequelae in six patients treated with allogeneic HSCT. All patients received a reduced-intensity conditioning (RIC) regimen consisting of fludarabine, cyclophosphamide or melphalan, and rabbit anti-thymocyte globulin and/or low-dose total body/thoracic-abdominal/total lymphoid irradiation, followed by allogeneic bone marrow or cord blood transplantation from unrelated donors between 4 and 18 months of age. All patients survived and achieved stable engraftment and complete chimerization with the donor type. Moreover, no patient experienced severe regimen-related toxicities, and only lower grades of acute graft-versus-host disease were observed. Three patients treated with low-dose irradiation had relatively short stature compared to three patients not treated with irradiation. Therefore, allogeneic HSCT with RIC is an effective and feasible treatment for infants with MECOM-associated syndrome. Future studies are needed to evaluate the use of low-dose irradiation to avoid risks of other long-term sequelae.
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Affiliation(s)
- Masahiro Irie
- Department of Pediatrics, Tohoku University Graduate School of Medicine, 1-1 Seiryo-Machi, Aoba-Ku, Sendai, Miyagi, 980-8574, Japan
| | - Tetsuya Niihori
- Department of Medical Genetics, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Tomohiro Nakano
- Department of Pediatrics, Tohoku University Graduate School of Medicine, 1-1 Seiryo-Machi, Aoba-Ku, Sendai, Miyagi, 980-8574, Japan
| | - Tasuku Suzuki
- Department of Pediatrics, Tohoku University Graduate School of Medicine, 1-1 Seiryo-Machi, Aoba-Ku, Sendai, Miyagi, 980-8574, Japan
| | - Saori Katayama
- Department of Pediatrics, Tohoku University Graduate School of Medicine, 1-1 Seiryo-Machi, Aoba-Ku, Sendai, Miyagi, 980-8574, Japan
| | - Kunihiko Moriya
- Department of Pediatrics, Tohoku University Graduate School of Medicine, 1-1 Seiryo-Machi, Aoba-Ku, Sendai, Miyagi, 980-8574, Japan
| | - Hidetaka Niizuma
- Department of Pediatrics, Tohoku University Graduate School of Medicine, 1-1 Seiryo-Machi, Aoba-Ku, Sendai, Miyagi, 980-8574, Japan
| | - Nobu Suzuki
- Department of Hematology and Oncology, Miyagi Children's Hospital, Miyagi, Japan
| | - Yuka Saito-Nanjo
- Department of Hematology and Oncology, Miyagi Children's Hospital, Miyagi, Japan
| | - Masaei Onuma
- Department of Hematology and Oncology, Miyagi Children's Hospital, Miyagi, Japan
| | - Takeshi Rikiishi
- Department of Hematology and Oncology, Miyagi Children's Hospital, Miyagi, Japan
| | - Atsushi Sato
- Department of Hematology and Oncology, Miyagi Children's Hospital, Miyagi, Japan
| | - Mayumi Hangai
- Department of Pediatrics, The University of Tokyo, Tokyo, Japan
| | - Mitsuteru Hiwatari
- Department of Pediatrics, The University of Tokyo, Tokyo, Japan.,Department of Pediatrics, School of Medicine, Teikyo University, Tokyo, Japan
| | - Junji Ikeda
- Department of Pediatrics, Yokohama City University Graduate School of Medicine, Kanagawa, Japan
| | - Reo Tanoshima
- Department of Pediatrics, Yokohama City University Graduate School of Medicine, Kanagawa, Japan
| | - Norio Shiba
- Department of Pediatrics, Yokohama City University Graduate School of Medicine, Kanagawa, Japan
| | - Yuki Yuza
- Department of Hematology and Oncology, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Nobuyuki Yamamoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Hyogo, Japan
| | - Yoshiko Hashii
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan.,Department of Pediatrics, Osaka International Cancer Institute, Osaka, Japan
| | - Motohiro Kato
- Department of Pediatrics, The University of Tokyo, Tokyo, Japan.,Children's Cancer Center, National Center for Child Health and Development, Tokyo, Japan
| | - Junko Takita
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Miho Maeda
- Department of Pediatrics, Nippon Medical School, Tokyo, Japan
| | - Yoko Aoki
- Department of Medical Genetics, Tohoku University Graduate School of Medicine, Miyagi, Japan
| | - Masue Imaizumi
- Department of Hematology and Oncology, Miyagi Children's Hospital, Miyagi, Japan
| | - Yoji Sasahara
- Department of Pediatrics, Tohoku University Graduate School of Medicine, 1-1 Seiryo-Machi, Aoba-Ku, Sendai, Miyagi, 980-8574, Japan.
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8
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Phenotypic heterogeneity in individuals with MECOM variants in 2 families. Blood Adv 2022; 6:5257-5261. [DOI: 10.1182/bloodadvances.2020003812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 12/23/2021] [Indexed: 11/20/2022] Open
Abstract
MECOM encodes the transcriptional regulators, EVI1 and MDS1-EVI1, from two distinct transcription start sites. EVI1 plays important roles in hematopoiesis and stem cell self-renewal. Recently, our group and others revealed that individuals with MECOM variants present diverse hematological and skeletal defects, including radioulnar synostosis (RUS). In the present study, we analyzed two families suspected with MECOM-associated syndrome. In family 1, a MECOM splicing variant (c.2285+1G>A) was identified in an individual with bone marrow failure (TRS4) without RUS and her mother, who had mild leukocytopenia, thrombocytopenia, and bilateral RUS. A copy neutral loss of heterozygosity decreasing the variant allele frequency was observed in the bone marrow of TRS4 and the peripheral blood leukocytes of her mother. However, TRS4 remained transfusion-dependent. In family 2, a MECOM variant (c.2208-4A>G), which was predicted to cause a cryptic acceptor site that results in a 3-base insertion (an insertion of Ser) in the mRNA, was identified in the proband, with bone marrow failure; this variant was also observed in her brother and father, both of whom have skeletal malformations, but no cytopenia. RT-PCR using leukocytes revealed a transcript with a 3-bp insertion in the proband, her brother, and the father, suggesting that the transcript variant with a 3-bp insertion is independent of blood phenotype. Collectively, these results suggest the presence of intrafamilial clinical heterogeneity in both families with MECOM splicing variants. Somatic genetic event may complicate the understanding of clinical variability among family members.
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9
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Taniguchi R, Muramatsu H, Okuno Y, Yoshida T, Wakamatsu M, Hamada M, Shirota C, Sumida W, Hinoki A, Tainaka T, Gotoh Y, Tsuzuki T, Tanaka Y, Kojima S, Uchida H, Takahashi Y. A patient with very early onset FH-deficient renal cell carcinoma diagnosed at age seven. Fam Cancer 2021; 21:337-341. [PMID: 34156580 DOI: 10.1007/s10689-021-00268-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 06/13/2021] [Indexed: 12/20/2022]
Abstract
Hereditary leiomyomatosis and renal cell cancer (HLRCC) is caused by heterozygous germline variants in the fumarate hydratase (FH) gene and is associated with increased susceptibility to cutaneous leiomyomas, uterine leiomyomas, and renal cell carcinoma (RCC). HLRCC-associated RCC usually occurs in the middle age, with the median age being 40-44 years. This report describes a seven-year-old (84-month-old) male who developed a large right kidney tumor with multiple cystic lesions that contained enhanced solid components. There was no evidence of distant metastasis. The male patient underwent right nephrectomy and has been recovering well without metastasis or recurrence. Pathological examination revealed that tumor cells with relatively prominent nucleoli and surrounded by halos, were located in a limited area. Immunohistochemical staining was negative for FH. Whole-exome sequencing identified his germline variant in the FH gene and its loss of heterozygosity in the tumor. At nine years (114 months) of age, the male patient showed no recurrence of the tumor. This was the youngest-onset case of HLRCC-associated RCC to date. This report may affect the starting age for future RCC-surveillance programs for patients with HLRCC.
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Affiliation(s)
- Rieko Taniguchi
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Hideki Muramatsu
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
| | - Yusuke Okuno
- Medical Genomics Center, Nagoya University Hospital, Nagoya, Japan
| | - Taro Yoshida
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Manabu Wakamatsu
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Motoharu Hamada
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Chiyoe Shirota
- Department of Pediatric Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Wataru Sumida
- Department of Pediatric Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akinari Hinoki
- Department of Rare/ Intractable Cancer Analysis Research, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Takahisa Tainaka
- Department of Pediatric Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshimitsu Gotoh
- Department of Pediatric Nephrology, Japanese Red Cross Nagoya Daini Hospital, Nagoya, Japan
| | - Toyonori Tsuzuki
- Department of Surgical Pathology, Aichi Medical University Hospital, Nagakute, Japan
| | - Yukichi Tanaka
- Department of Pathology, Kanagawa Children's Medical Center, Kanagawa, Japan
| | - Seiji Kojima
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan
| | - Hiroo Uchida
- Department of Pediatric Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshiyuki Takahashi
- Department of Pediatrics, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, 466-8550, Japan.
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MECOM-associated syndrome: a heterogeneous inherited bone marrow failure syndrome with amegakaryocytic thrombocytopenia. Blood Adv 2019. [PMID: 29540340 DOI: 10.1182/bloodadvances.2018016501] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Heterozygous mutations in MECOM (MDS1 and EVI1 complex locus) have been reported to be causative of a rare association of congenital amegakaryocytic thrombocytopenia and radioulnar synostosis. Here we report on 12 patients with congenital hypomegakaryocytic thrombocytopenia caused by MECOM mutations (including 10 novel mutations). The mutations affected different functional domains of the EVI1 protein. The spectrum of phenotypes was much broader than initially reported for the first 3 patients; we found familial as well as sporadic cases, and the clinical spectrum ranged from isolated radioulnar synostosis with no or mild hematological involvement to severe bone marrow failure without obvious skeletal abnormality. The clinical picture included radioulnar synostosis, bone marrow failure, clinodactyly, cardiac and renal malformations, B-cell deficiency, and presenile hearing loss. No single clinical manifestation was detected in all patients affected by MECOM mutations. Radioulnar synostosis and B-cell deficiency were observed only in patients with mutations affecting a short region in the C-terminal zinc finger domain of EVI1. We propose the term MECOM-associated syndrome for this heterogeneous hereditary disease and inclusion of MECOM sequencing in the diagnostic workup of congenital bone marrow failure.
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