Abstract: TH-PO470
Phenotypic Spectrum Analysis and Molecular Mechanism Study of PAX2 Variants in the Chinese Population
Session Information
- Genetic Diseases: Glomerulopathies - I
November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1202 Genetic Diseases of the Kidneys: Non-Cystic
Authors
- Shen, Qian, Children's Hospital of Fudan University, Shanghai, China
- Xu, Hong, Children's Hospital of Fudan University, Shanghai, China
- Sun, Man Qing, Children's Hospital of Fudan University, Shanghai, China
Background
Congenital anomalies of the kidneys and urinary tract (CAKUT) is the leading cause of renal failure in children. Dysfunction of transcription factors can cause human and mouse CAKUT. Variants in PAX2 gene are widely reported to cause CAKUT with or without optic nerve abnormalities (Renal coloboma syndrome, RCS). Interestingly, heterozygous variants in PAX2 gene were also reported to cause Focal Segmental Glomerulosclerosis (FSGS). However, the mechanism is not well studied.
Methods
Variants in PAX2 gene and phenotypic spectrum from 16 individuals were summarized. Functional effects of different PAX2 variants were confirmed by constructing wild-type and mutant PAX2 overexpression plasmids. Minigene splicing assay was performed to test function of splicing variants. The plasmid of mutant PAX2 gene associated with FSGS was also transfected into human podocytes. Meanwhile, we further performed RNA-seq to analysis the different signaling between different phenotype.
Results
A total of 16 individuals with 12 different variants PAX2 variants were included in this study. Among them, nonsense mutations (5/16, 31%) were the main type of variation. One variant caused FSGS phenotype. In vitro study, nonsense mutations produces truncated proteins and damaging the protein stability. Different PAX2 gene variant proteins all significantly reduced the expression level of PRS4-luc. Both c.43+1G>A and c.213-2A>G in PAX2 gene demonstrated abnormal splicing of mRNA. The FSGS phenotype-associated PAX2 gene variant c.975C>A mainly shows damage to podocytes dominated by mitochondrial dysfunction. Furthermore, by RNA-seq, we showed PAX2 gene mutations associated with CAKUT phenotype, mainly involved in PI3K-Akt signaling pathway, neural development, extracellular matrix and other factors,while FSGS phenotype-associated PAX2 gene variants, mainly involved in cell adhesion, actin cytoskeleton related to podocyte development.
Conclusion
Our study showed different PAX2 gene variants cause different phenotype. Functional study showed PAX2 gene mutations associated with CAKUT phenotype are mainly involved in PI3K-Akt molecular pathways, neural development and other factors, while PAX2 gene mutations associated with FSGS phenotype are mainly involved in cell adhesion, actin cytoskeleton and the development of podocytes.