Deciphering the Genetic Basis of Focal Segmental Glomerulosclerosis Using Next-Generation Sequencing

Abstract Introduction: Focal Segmental Glomerulosclerosis (FSGS) is a heterogeneous glomerular disorder characterized by segmental sclerosis of one or more glomeruli and prominent proteinuria. Podocyte injury underlies the pathogenesis and compromises the renal filtration barrier. FSGS can be classified into primary, genetic, and secondary forms, with secondary causes including maladaptive, infection-related, and drug-induced mechanisms. These subtypes differ in etiology, clinical course, treatment response, and prognosis. Methods Whole exome sequencing was conducted on patients with biopsy-proven FSGS to identify the underlying molecular etiopathogenesis utilizing the Illumina NextSeq2000 system. Bioinformatic analyses were performed on the SOPHIA DDM platform. Sanger sequencing was conducted to validate the detected variant in the proband and to conduct segregation analysis in her family members. Results Among the 50 FSGS patients, no clinically relevant variants were identified by NGS in 25 individuals. Known pathogenic variants in SDCCAG8 , NPHS2 , and COQ8B were confirmed by Sanger sequencing. Three novel variants in MAPKBP1 , ARHGAP24 , and PODXL were identified and validated through familial segregation analysis. Variants in seven probands were confirmed by Sanger sequencing, while 12 novel VUS variants failed to segregate with disease in family studies. Conclusion This study highlights the value of genetic analysis in understanding its molecular basis. Integration of WES with detailed clinical evaluation allowed the identification of multiple variants, improving insight into FSGS pathogenesis. Limitations include the lack of functional validation for novel variants and the inability to perform segregation analyses in some families.