The First Observation and Diagnosis of Nail-Patella Syndrome Using LV-SEM: GBM Abnormalities Mimicking Alport Syndrome.

Abstract

We report the case of a 32-year-old man with a family history of nail patella syndrome (NPS) who presented with severe kidney dysfunction, hematuria, and proteinuria. A renal biopsy was performed to rule out other kidney diseases and obtain information on the possibility of future renal transplantation, as the renal morphology was relatively preserved and abnormal urinary findings indicative of nephritis. The scarcity of viable glomeruli for conventional transmission electron microscopy (TEM) prompted us to use low-vacuum scanning electron microscopy (LV-SEM) on light microscopy samples. LV-SEM analysis revealed characteristic glomerular basement membrane (GBM) alterations, including a coarse meshwork structure and a ragged pattern, similar to the GBM changes observed in Alport syndrome. These findings, combined with genetic testing results, confirmed the diagnosis of NPS-associated nephropathy. This case represents the first reported use of LV-SEM for observing and diagnosing NPS-associated nephropathy, demonstrating its potential as a valuable diagnostic tool wherein sample availability or quality limits the conventional TEM.