Functional characterization of 105 Factor H variants associated with HUS:lessons for variant classification

Autor: Emilia Arjona, Malkoa Michelena, Elena Gómez-Rubio, Richard J.H. Smith, Rui-Ru Ji, Renee X. Goodfellow, Yuzhou Zhang, Héctor Martín Merinero, Santiago Rodríguez de Córdoba, Guillermo del Angel
Přispěvatelé: Ministerio de Economía y Competitividad (España), Comunidad de Madrid, National Institute of Diabetes and Digestive and Kidney Diseases (US), Alexion Pharmaceuticals, Oxford PharmaGenesis, Martín Merinero, Héctor, Arjona, Emilia, Del Ángel, Guillermo, Gomez-Rubio, Elena, Ji, Rui-Ru, Rodríguez de Córdoba, Santiago, Martín Merinero, Héctor [0000-0002-9094-5934], Arjona, Emilia [0000-0002-0753-3657], Del Ángel, Guillermo [0000-0002-0104-1563], Gomez-Rubio, Elena [0000-0002-8037-4007], Ji, Rui-Ru [0000-0003-3795-9840], Rodríguez de Córdoba, Santiago [0000-0001-6401-1874]
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Digital.CSIC. Repositorio Institucional del CSIC
instname
Blood
Digital.CSIC: Repositorio Institucional del CSIC
Consejo Superior de Investigaciones Científicas (CSIC)
Popis: Atypical hemolytic uremic syndrome (aHUS) is a life-threatening thrombotic microangiopathy, and complement dysregulation due to pathogenic variants in factor H (FH) is a recognized cause. The clinical utility of genetic testing in aHUS is limited by the large number of variants reported as “variants of uncertain significance” for the FH gene. Martin Merinero and colleagues functionally characterized 105 FH variants and provide critical data that improve understanding of their clinical significance and should better informclinical practice.
Key Points Functional characterization of 105 aHUS-associated FH variants reveals limitations of routinely used variant-classification methods.Adapting prediction algorithms to FH domains markedly improves variant classification, and rarity in control databases can be misleading.
Visual Abstract
Atypical hemolytic uremic syndrome (aHUS) is a life-threatening thrombotic microangiopathy that can progress, when untreated, to end-stage renal disease. Most frequently, aHUS is caused by complement dysregulation due to pathogenic variants in genes that encode complement components and regulators. Among these genes, the factor H (FH) gene, CFH, presents with the highest frequency (15% to 20%) of variants and is associated with the poorest prognosis. Correct classification of CFH variants as pathogenic or benign is essential to clinical care but remains challenging owing to the dearth of functional studies. As a result, significant numbers of variants are reported as variants of uncertain significance. To address this knowledge gap, we expressed and functionally characterized 105 aHUS-associated FH variants. All FH variants were categorized as pathogenic or benign and, for each, we fully documented the nature of the pathogenicity. Twenty-six previously characterized FH variants were used as controls to validate and confirm the robustness of the functional assays used. Of the remaining 79 uncharacterized variants, only 29 (36.7%) alter FH expression or function in vitro and, therefore, are proposed to be pathogenic. We show that rarity in control databases is not informative for variant classification, and we identify important limitations in applying prediction algorithms to FH variants. Based on structural and functional data, we suggest ways to circumvent these difficulties and, thereby, improve variant classification. Our work highlights the need for functional assays to interpret FH variants accurately if clinical care of patients with aHUS is to be individualized and optimized.
Databáze: OpenAIRE