A 16-year-old boy has persistent microscopic haematuria, bilateral sensorineural hearing loss, and anterior lenticonus. Renal biopsy light microscopy is non-specific. Which electron microscopic finding establishes the diagnosis?

• A Diffuse effacement of epithelial foot processes
• B Subepithelial hump-shaped immune deposits
• C Linear IgG deposition along the glomerular basement membrane on immunofluorescence
• D Alternating thickening and thinning of the glomerular basement membrane with splitting into a basket-weave pattern ✓

Explanation

Alport syndrome results from mutations in type IV collagen genes, classically COL4A5 on the X chromosome, producing abnormal GBM assembly. Electron microscopy shows irregular alternating thinning and thickening with lamellation and splitting of the lamina densa, described as a basket-weave appearance. Foot process effacement alone suggests podocytopathy, subepithelial humps indicate post-infectious GN, and linear IgG staining defines anti-GBM disease, none of which fits the triad of haematuria, deafness, and ocular lesions.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.