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Allegrini B, Jedele S, David Nguyen L, Mignotet M, Rapetti-Mauss R, Etchebest C, Fenneteau O, Loubat A, Boutet A, Thomas C, Durin J, Petit A, Badens C, Garçon L, Da Costa L, Guizouarn H. New KCNN4 Variants Associated With Anemia: Stomatocytosis Without Erythrocyte Dehydration. Front Physiol 2022; 13:918620. [PMID: 36003639 PMCID: PMC9393219 DOI: 10.3389/fphys.2022.918620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Abstract
The K+ channel activated by the Ca2+, KCNN4, has been shown to contribute to red blood cell dehydration in the rare hereditary hemolytic anemia, the dehydrated hereditary stomatocytosis. We report two de novo mutations on KCNN4, We reported two de novo mutations on KCNN4, V222L and H340N, characterized at the molecular, cellular and clinical levels. Whereas both mutations were shown to increase the calcium sensitivity of the K+ channel, leading to channel opening for lower calcium concentrations compared to WT KCNN4 channel, there was no obvious red blood cell dehydration in patients carrying one or the other mutation. The clinical phenotype was greatly different between carriers of the mutated gene ranging from severe anemia for one patient to a single episode of anemia for the other patient or no documented sign of anemia for the parents who also carried the mutation. These data compared to already published KCNN4 mutations question the role of KCNN4 gain-of-function mutations in hydration status and viability of red blood cells in bloodstream.
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Affiliation(s)
- B. Allegrini
- Université Côte d’Azur, CNRS, INSERM, iBV, Nice, France
| | - S. Jedele
- Université Paris Cité and Université des Antilles, Inserm, BIGR, Paris, France
| | - L. David Nguyen
- Université Paris Cité, Paris, France
- AP-HP, Service d’Hématologie Biologique, Hôpital R. Debré, Paris, France
| | - M. Mignotet
- Université Côte d’Azur, CNRS, INSERM, iBV, Nice, France
| | | | - C. Etchebest
- Université Paris Cité and Université des Antilles, Inserm, BIGR, Paris, France
| | - O. Fenneteau
- AP-HP, Service d’Hématologie Biologique, Hôpital R. Debré, Paris, France
| | - A. Loubat
- Université Côte d’Azur, CNRS, INSERM, iBV, Nice, France
| | - A. Boutet
- Hôpital Saint Nazaire, Saint-Nazaire, France
| | - C. Thomas
- CHU Nantes, Service Oncologie-hématologie et Immunologie Pédiatrique, Nantes, France
| | - J. Durin
- Sorbonne Université, AP-HP, Hôpital Armand Trousseau, Service d'Hématologie Oncologie Pédiatrique, Paris, France
| | - A. Petit
- Sorbonne Université, AP-HP, Hôpital Armand Trousseau, Service d'Hématologie Oncologie Pédiatrique, Paris, France
| | - C. Badens
- Aix Marseille Univ, INSERM, MMG, Marseille, France
- AP-HM, Department of Genetic, Marseille, France
| | - L. Garçon
- Université Picardie Jules Verne, Unité EA4666 Hematim, Amiens, France
- CHU Amiens, Service d'Hématologie Biologique, Amiens, France
| | - L. Da Costa
- Université Paris Cité, Paris, France
- AP-HP, Service d’Hématologie Biologique, Hôpital R. Debré, Paris, France
- Université Picardie Jules Verne, Unité EA4666 Hematim, Amiens, France
| | - H. Guizouarn
- Université Côte d’Azur, CNRS, INSERM, iBV, Nice, France
- *Correspondence: H. Guizouarn,
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Wong P. A hypothesis of target cell formation in sickle cell disease. Med Hypotheses 2016; 93:102-5. [PMID: 27372866 DOI: 10.1016/j.mehy.2016.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 05/18/2016] [Accepted: 05/19/2016] [Indexed: 11/22/2022]
Abstract
A fraction of erythrocytes appear as target cells in stained blood smears in sickle cell disease, due to a inheritance of the hemoglobin variant Hb S, polymerizing upon deoxygenation. These cells appear in a three dimension as thin cups. A process of their formation in this disease is proposed based on a band 3-based mechanism of the erythrocyte shape control, able to explain the erythrocyte echinocytosis by glucose depletion. It indicates that their formation is due to a stomatocytogenic slow outward transport of the dibasic form of endogenous Pi with an H(+) by band 3, promoted by the decrease of the Donnan ratio, which decreases cell pH and volume, attributed by a decrease of cell KCl concentration by the higher efflux of K(+)Cl(-) cotransport and Ca(2+) activation of the Gardos channel. Its implications are briefly discussed with respect to target cells per se, target cell formation in other hemoglobinopathies, acquired and inherited disorders of the lipid metabolism and dehydrated hereditary stomatocytosis as well as a stomatocyte presence in a double heterozygote of Hb S and Hb C and of an involvement of the process of target cell formation in acanthocytosis in acquired and inherited disorders.
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Affiliation(s)
- P Wong
- Laboratoire de Chimie des Protéines, Montréal, Québec, Canada.
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