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Hirose R, Tsurutani Y, Sugisawa C, Inoue K, Suematsu S, Nagata M, Hasegawa N, Kakuta Y, Yonamine M, Takekoshi K, Kimura N, Saito J, Nishikawa T. Hereditary pheochromocytoma/paraganglioma syndrome with a novel mutation in the succinate dehydrogenase subunit B gene in a Japanese family: two case reports. J Med Case Rep 2021; 15:282. [PMID: 34020699 PMCID: PMC8140422 DOI: 10.1186/s13256-021-02852-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/05/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Pheochromocytoma and paraganglioma caused by succinate dehydrogenase gene mutations is called hereditary pheochromocytoma/paraganglioma syndrome. In particular, succinate dehydrogenase subunit B mutations are important because they are strongly associated with the malignant behavior of pheochromocytoma and paraganglioma . This is a case report of a family of hereditary pheochromocytoma/paraganglioma syndrome carrying a novel mutation in succinate dehydrogenase subunit B. CASE PRESENTATION A 19-year-old Japanese woman, whose father died of metastatic paraganglioma, was diagnosed with abdominal paraganglioma, and underwent total resection. Succinate dehydrogenase subunit B genetic testing detected a splice-site mutation, c.424-2delA, in her germline and paraganglioma tissue. Afterwards, the same succinate dehydrogenase subunit B mutation was detected in her father's paraganglioma tissues. In silico analysis predicted the mutation as "disease causing." She is under close follow-up, and no recurrence or metastasis has been observed for 4 years since surgery. CONCLUSIONS We detected a novel succinate dehydrogenase subunit B mutation, c.424-2delA, in a Japanese family afflicted with hereditary pheochromocytoma/paraganglioma syndrome and found the mutation to be responsible for hereditary pheochromocytoma/paraganglioma syndrome. This case emphasizes the importance of performing genetic testing for patients with pheochromocytoma and paraganglioma suspected of harboring the succinate dehydrogenase subunit B mutation (that is, metastatic, extra-adrenal, multiple, early onset, and family history of pheochromocytoma and paraganglioma) and offer surveillance screening to mutation carriers.
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Affiliation(s)
- Rei Hirose
- Endocrinology and Diabetes Center, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kouhoku-ku, Yokohama, Kanagawa, 222-0036, Japan
| | - Yuya Tsurutani
- Endocrinology and Diabetes Center, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kouhoku-ku, Yokohama, Kanagawa, 222-0036, Japan.
| | - Chiho Sugisawa
- Endocrinology and Diabetes Center, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kouhoku-ku, Yokohama, Kanagawa, 222-0036, Japan
| | - Kosuke Inoue
- Endocrinology and Diabetes Center, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kouhoku-ku, Yokohama, Kanagawa, 222-0036, Japan.,Department of Epidemiology, UCLA Fielding School of Public Health, 650 Charles E. Young Dr. South, 16-035 Center for Health Sciences, Los Angeles, CA, USA
| | - Sachiko Suematsu
- Endocrinology and Diabetes Center, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kouhoku-ku, Yokohama, Kanagawa, 222-0036, Japan
| | - Maki Nagata
- Department of Urology, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kouhoku-ku, Yokohama, Kanagawa, 222-0036, Japan
| | - Naoki Hasegawa
- Department of Pathology, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kouhoku-ku, Yokohama, Kanagawa, 222-0036, Japan
| | - Yukio Kakuta
- Department of Pathology, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kouhoku-ku, Yokohama, Kanagawa, 222-0036, Japan
| | - Masato Yonamine
- Laboratory of Laboratory/Sports Medicine, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Kazuhiro Takekoshi
- Laboratory of Laboratory/Sports Medicine, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8577, Japan
| | - Noriko Kimura
- Department of Diagnostic Pathology, National Hospital Organization Hakodate Hospital, 18-16 Kawahara-cho, Hakodate, Hokkaido, 041-8512, Japan
| | - Jun Saito
- Endocrinology and Diabetes Center, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kouhoku-ku, Yokohama, Kanagawa, 222-0036, Japan
| | - Tetsuo Nishikawa
- Endocrinology and Diabetes Center, Yokohama Rosai Hospital, 3211 Kozukue-cho, Kouhoku-ku, Yokohama, Kanagawa, 222-0036, Japan
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Gao W, Xu Y, Liu H, Gao M, Cao Q, Wang Y, Cui L, Huang R, Shen Y, Li S, Yang H, Chen Y, Li C, Yu H, Li W, Shen G. Characterization of missense mutations in the signal peptide and propeptide of FIX in hemophilia B by a cell-based assay. Blood Adv 2020; 4:3659-3667. [PMID: 32766856 PMCID: PMC7422117 DOI: 10.1182/bloodadvances.2020002520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 07/06/2020] [Indexed: 11/20/2022] Open
Abstract
Many mutations in the signal peptide and propeptide of factor IX (FIX) cause hemophilia B. A FIX variants database reports 28 unique missense mutations in these regions that lead to FIX deficiency, but the underlying mechanism is known only for the mutations on R43 that interfere with propeptide cleavage. It remains unclear how other mutations result in FIX deficiency and why patients carrying the same mutation have different bleeding tendencies. Here, we modify a cell-based reporter assay to characterize the missense mutations in the signal peptide and propeptide of FIX. The results show that the level of secreted conformation-specific reporter (SCSR), which has a functional γ-carboxyglutamate (Gla) domain of FIX, decreases significantly in most mutations. The decreased SCSR level is consistent with FIX deficiency in hemophilia B patients. Moreover, we find that the decrease in the SCSR level is caused by several distinct mechanisms, including interfering with cotranslational translocation into the endoplasmic reticulum, protein secretion, γ-carboxylation of the Gla domain, and cleavage of the signal peptide or propeptide. Importantly, our results also show that the SCSR levels of most signal peptide and propeptide mutations increase with vitamin K concentration, suggesting that the heterogeneity of bleeding tendencies may be related to vitamin K levels in the body. Thus, oral administration of vitamin K may alleviate the severity of bleeding tendencies in patients with missense mutations in the FIX signal peptide and propeptide regions.
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Affiliation(s)
- Wenwen Gao
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Yaqi Xu
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Hongli Liu
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Meng Gao
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Qing Cao
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Yiyi Wang
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Longteng Cui
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Rong Huang
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Yan Shen
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Sanqiang Li
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Haiping Yang
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
- First Affiliated Hospital, Henan University of Science and Technology, Luoyang, People's Republic of China
| | - Yixiang Chen
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
| | - Chaokun Li
- Sino-UK Joint Laboratory for Brain Function and Injury, School of Basic Medical Sciences, and
| | - Haichuan Yu
- Department of Biochemistry and Molecular Biology, School of Medical Laboratory, Xinxiang Medical University, Xinxiang, People's Republic of China; and
| | - Weikai Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO
| | - Guomin Shen
- Department of Medical Genetics, Institute of Hemostasis and Thrombosis, School of Basic Medical Sciences, and
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Rishavy MA, Hallgren KW, Zhang H, Runge KW, Berkner KL. Exon 2 skipping eliminates γ-glutamyl carboxylase activity, indicating a partial splicing defect in a patient with vitamin K clotting factor deficiency. J Thromb Haemost 2019; 17:1053-1063. [PMID: 31009158 PMCID: PMC7181818 DOI: 10.1111/jth.14456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/12/2019] [Indexed: 12/01/2022]
Abstract
Essentials A carboxylase mutation that impairs splicing to delete exon 2 sequences was previously reported. We found that the mutant was inactive for vitamin K-dependent (VKD) protein carboxylation. An incomplete splicing defect likely accounts for VKD clotting activity observed in the patient. The results indicate the importance of proper carboxylase embedment in the membrane for function. BACKGROUND Mutations in the γ-glutamyl carboxylase (GGCX), which is required for vitamin K-dependent (VKD) protein activation, can result in vitamin K clotting factor deficiency (VKCFD1). A recent report described a VKCFD1 patient with a homozygous carboxylase mutation that altered splicing and deleted exon 2 (Δ2GGCX). Only Δ2GGCX RNA was observed in the patient. OBJECTIVES Loss of exon 2 results in the deletion of carboxylase sequences thought to be important for membrane topology and consequent function. Carboxylase activity is required for life, and we therefore tested whether the Δ2GGCX mutant is active. METHODS HEK 293 cells were edited by the use of CRISPR-Cas9 to eliminate endogenous carboxylase. Recombinant wild-type GGCX and recombinant Δ2GGCX were then expressed and tested for carboxylation of the VKD protein factor IX. A second approach was used to monitor carboxylation biochemically, using recombinant carboxylases expressed in insect cells that lack endogenous carboxylase. RESULTS AND CONCLUSIONS Δ2GGCX activity was undetectable in both assays, which is strikingly different from the low levels of carboxylase activity observed with other VKCFD1 mutants. The similarity in clotting function between patients with Δ2GGCX and these mutations must therefore arise from a novel mechanism. Low levels of properly spliced carboxylase RNA that produce full-length protein would not have been observed in the previous study. The results suggest that the splicing defect is incomplete. Δ2GGCX RNA has been detected in normal human liver, and has been designated carboxylase isoform 2; however, Δ2GGCX protein was not observed in normal human liver. The lack of activity and protein expression suggest that isoform 2 is not physiologically relevant to normal VKD protein carboxylation.
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Affiliation(s)
- Mark A Rishavy
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine at CWRU, Cleveland Clinic, Cleveland, Ohio
| | - Kevin W Hallgren
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine at CWRU, Cleveland Clinic, Cleveland, Ohio
| | - Haitao Zhang
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine at CWRU, Cleveland Clinic, Cleveland, Ohio
| | - Kurt W Runge
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine at CWRU, Cleveland Clinic, Cleveland, Ohio
| | - Kathleen L Berkner
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine at CWRU, Cleveland Clinic, Cleveland, Ohio
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Warfarin and vitamin K epoxide reductase: a molecular accounting for observed inhibition. Blood 2018; 132:647-657. [PMID: 29743176 DOI: 10.1182/blood-2018-01-830901] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 05/06/2018] [Indexed: 01/05/2023] Open
Abstract
Vitamin K epoxide reductase (VKOR), an endoplasmic reticulum membrane protein, is the key enzyme for vitamin K-dependent carboxylation, a posttranslational modification that is essential for the biological functions of coagulation factors. VKOR is the target of the most widely prescribed oral anticoagulant, warfarin. However, the topological structure of VKOR and the mechanism of warfarin's inhibition of VKOR remain elusive. Additionally, it is not clear why warfarin-resistant VKOR mutations identified in patients significantly decrease warfarin's binding affinity, but have only a minor effect on vitamin K binding. Here, we used immunofluorescence confocal imaging of VKOR in live mammalian cells and PEGylation of VKOR's endogenous cytoplasmic-accessible cysteines in intact microsomes to probe the membrane topology of human VKOR. Our results show that the disputed loop sequence between the first and second transmembrane (TM) domain of VKOR is located in the cytoplasm, supporting a 3-TM topological structure of human VKOR. Using molecular dynamics (MD) simulations, a T-shaped stacking interaction between warfarin and tyrosine residue 139, within the proposed TY139A warfarin-binding motif, was observed. Furthermore, a reversible dynamic warfarin-binding pocket opening and conformational changes were observed when warfarin binds to VKOR. Several residues (Y25, A26, and Y139) were found essential for warfarin binding to VKOR by MD simulations, and these were confirmed by the functional study of VKOR and its mutants in their native milieu using a cell-based assay. Our findings provide new insights into the dynamics of the binding of warfarin to VKOR, as well as into warfarin's mechanism of anticoagulation.
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GGCX-Associated Phenotypes: An Overview in Search of Genotype-Phenotype Correlations. Int J Mol Sci 2017; 18:ijms18020240. [PMID: 28125048 PMCID: PMC5343777 DOI: 10.3390/ijms18020240] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/21/2016] [Accepted: 01/13/2017] [Indexed: 11/16/2022] Open
Abstract
Gamma-carboxylation, performed by gamma-glutamyl carboxylase (GGCX), is an enzymatic process essential for activating vitamin K-dependent proteins (VKDP) with important functions in various biological processes. Mutations in the encoding GGCX gene are associated with multiple phenotypes, amongst which vitamin K-dependent coagulation factor deficiency (VKCFD1) is best known. Other patients have skin, eye, heart or bone manifestations. As genotype–phenotype correlations were never described, literature was systematically reviewed in search of patients with at least one GGCX mutation with a phenotypic description, resulting in a case series of 47 patients. Though this number was too low for statistically valid correlations—a frequent problem in orphan diseases—we demonstrate the crucial role of the horizontally transferred transmembrane domain in developing cardiac and bone manifestations. Moreover, natural history suggests ageing as the principal determinant to develop skin and eye symptoms. VKCFD1 symptoms seemed more severe in patients with both mutations in the same protein domain, though this could not be linked to a more perturbed coagulation factor function. Finally, distinct GGCX functional domains might be dedicated to carboxylation of very specific VKDP. In conclusion, this systematic review suggests that there indeed may be genotype–phenotype correlations for GGCX-related phenotypes, which can guide patient counseling and management.
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