A Case Report of a Patient with COQ8B Nephropathy Manifesting Atypical Renal Pathological Changes.

Background: COQ8B nephropathy is a hereditary mitochondrial kidney disease. Most cases present with steroidresistant nephrotic syndrome and focal segmental glomerulosclerosis, whereas this patient exhibited asymptomatic isolated proteinuria and mild renal histopathology. Methods: Appropriate laboratory tests, abdominal ultrasonography, renal biopsy, and whole exome sequencing were performed to explore the cause of the disease. Results: Laboratory results revealed that the patient was asymptomatic. Abdominal ultrasonography confirmed left renal vein nutcracker. Renal histopathology showed mild mesangial proliferation. An unreported splice mutation in the COQ8B (c.893+2T>A) gene was identified by whole exome sequencing. Conclusions: COQ8B nephropathy is an emerging cause of isolated proteinuria, particularly prevalent among adolescents. For nephritis of unknown etiology following renal biopsy, prompt consideration of gene sequencing is advisable. [ABSTRACT FROM AUTHOR]