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Dirim AB, Safak S, Balci MC, Ozyavuz P, Garayeva N, Tiryaki TO, Oto OA, Ozluk Y, Kilicaslan I, Solakoglu S, Artan AS, Yazici H, Turkmen A, Ozturk S. Concurrent Cobalamin C and Plasminogen Deficiencies in a Patient with Chronic Thrombotic Microangiopathy. Nephron Clin Pract 2023; 148:54-62. [PMID: 37611544 DOI: 10.1159/000533417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 07/07/2023] [Indexed: 08/25/2023] Open
Abstract
BACKGROUND Although most patients with atypical hemolytic uremic syndrome (aHUS) have variants in genes participating in alternative complement pathways, rare variants in non-complement pathway-related genes, including DGKE, INF2, MMACHC, PLG, and THBD, have also been described. CASE PRESENTATION We report an 18-year-old male patient with renal biopsy-proven chronic thrombotic microangiopathy that raised suspicion of aHUS. Whole-exome sequencing revealed a novel pathogenic homozygous MMACHC c.484G>T (p.Gly162Trp) variant. Subsequently, clinical and laboratory findings confirmed cobalamin C (Cbl C) deficiency. Also, homozygous missense c.1112C>T PLG (p.Thr371Ile) variant was detected (it had been reported as a variant of unknown significance). However, the low serum plasminogen (PLG) activity proved the pathogenicity of c.1112C>T. Hence, the patient was diagnosed with concurrent Cbl C and PLG deficiencies. Segregation analysis revealed that the mother and father had the same heterozygous PLG and MMACHC variants. PLG variants have generally been described in aHUS patients concomitant with complement gene variants in the literature; therefore, the association between aHUS and PLG variants is controversial. The possible contribution of PLG deficiency to thrombotic microangiopathy was also discussed in this case. CONCLUSION Non-complement-mediated aHUS is an exceptional disorder. A limited number of genes are involved in this entity. To our knowledge, this is the first aHUS patient diagnosed with both Cbl C and PLG deficiencies in the literature.
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Affiliation(s)
- Ahmet Burak Dirim
- Division of Nephrology, Department of Internal Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
- Department of Genetics, Istanbul University Aziz Sancar Institute of Experimental Medicine, Graduate School of Health Sciences, Istanbul University, Istanbul, Turkey
| | - Seda Safak
- Division of Nephrology, Department of Internal Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Mehmet Cihan Balci
- Division of Pediatric Metabolic Disorders, Department of Pediatrics, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Pelin Ozyavuz
- Department of Genetics, Haseki Teaching and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Nurane Garayeva
- Division of Nephrology, Department of Internal Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Tarik Onur Tiryaki
- Division of Hematology, Department of Internal Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Ozgur Akin Oto
- Division of Nephrology, Department of Internal Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Yasemin Ozluk
- Department of Pathology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Isin Kilicaslan
- Department of Pathology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Seyhun Solakoglu
- Department of Histology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Ayse Serra Artan
- Division of Nephrology, Department of Internal Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Halil Yazici
- Division of Nephrology, Department of Internal Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Aydin Turkmen
- Division of Nephrology, Department of Internal Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Savas Ozturk
- Division of Nephrology, Department of Internal Medicine, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
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