Collagenofibrotic Glomerulopathy Associated With Homozygous STAB2 and Heterozygous STAB1 Variants: A Case Report

This case report investigates the genetic basis of collagenofibrotic glomerulopathy (CG), a type of collagen type III glomerulopathy. It is a rare kidney disease characterized by collagen III deposition. A 47-year-old man with CG, born to consanguineous parents, underwent whole-exome sequencing. A homozygous truncating variant in STAB2 and a heterozygous variant in STAB1 were identified. Neither of the proteins encoded by STAB2 and STAB1 was expressed in the kidney glomeruli, suggesting a systemic mechanism for CG development. The patient's mother and brother, with homozygous or heterozygous STAB1 and heterozygous STAB2 variants, were unaffected. These observations suggest that the homozygous truncating variant of STAB2 was crucial for CG in our patient. This study provides initial evidence implicating STAB1 and STAB2 in CG pathogenesis. Further studies are needed to confirm the present findings, elucidate the roles of stabilin-1 and stabilin-2 in CG, and investigate their potential for systemic involvement.