Functional Characterization and Pharmacological Evaluation of a Novel GLA Missense Mutation Found in a Severely Affected Fabry Disease Family

Author(s):Show less -

Varela, Patricia ^[1] ; Mastroianni Kirsztajn, Gianna ^[2] ; Ferrer, Henrique ^[1] ; Aranda, Carolina ^[3] ; Wallbach, Krissia ^[3] ; Ferreira da Mata, Gustavo ^[2] ; Moura, Luiz A. ^[2] ; Moreira, Silvia R. ^[2] ; Mendes, Carmen ^[3] ; Curiati, Marco A. ^[3] ; Martins, Ana Maria ^[3] ; Bosco Pesquero, Joao ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Dept Biophys, Ctr Res & Mol Diagnost Genet Dis, Rua Pedro Toledo 669, 9 Andar, BR-04039032 Sao Paulo, SP - Brazil

^[2] Univ Fed Sao Paulo, Dept Med, Div Nephrol, Rua Pedro Toledo 669, 9 Andar, BR-04039032 Sao Paulo, SP - Brazil

^[3] Univ Fed Sao Paulo, Dept Pediat, Reference Ctr Inborn Errors Metab, Sao Paulo - Brazil

• Document type: Journal article
• Source: NEPHRON; v. 144, n. 3, p. 147-155, MAR 2020.
• Web of Science Citations: 1

Abstract

Background: Fabry disease (FD) is a rare X-linked storage disorder resulting from the deficient activity of the lysosomal hydrolase alpha-galactosidase A (alpha-Gal A). Here we describe a 23-year-old man with FD possessing a novel mutation in the GLA gene, the evaluation of his family, and the functional characterization of the novel variant. Methods: Two generations of a family were screened for FD by clinical symptoms and low enzymatic activity. This step was followed by DNA sequencing that showed a novel GLA missense mutation. To confirm the pathogenicity potential of the mutation, we employed site-directed polymerase chain reaction mutagenesis. GLA wild-type and mutant plasmids were transfected into mammalian cells; RNA and proteins were extracted for expression and analysis of enzymatic activity. Results: The patient presents the variant p.Asn34Asp in the GLA and had several manifestations of FD since adolescence. The investigation of the deficiency of alpha-Gal A was initiated due to stage 4 of chronic kidney disease. All family members carrying the novel mutation presented early symptoms, including index case's mother, who received a renal transplant when she was 35 years old. In silico and in vitro analysis confirmed the pathogenic potential of the mutation p.Asn34Asp showing that the enzyme had only 4% of residual activity due to protein misfolding. The ability of the pharmacological chaperone 1-deoxygalactonojirimycin to recover the mutant was confirmed, producing 37.5% of residual activity. Conclusion: In this work, we present a novel missense mutation in GLA that leads to the production of a catalytically competent alpha-Gal A, which is degraded before its delivery to the lysosome, promoting severe manifestations of FD, with a very similar disease course in affected men and women. (AU)

• FAPESP's process: 14/27198-8 - Establishment of a center of genetic and molecular research for clinical challenges
• Grantee: João Bosco Pesquero
• Support Opportunities: Research Projects - Thematic Grants