An 8-year-old boy has persistent microscopic haematuria detected on school screening. His mother had deafness and died of kidney failure at age 40. Audiometry confirms bilateral sensorineural hearing loss. Light microscopy of the biopsy is non-specific. What is the expected finding on electron microscopy?

• A Diffuse effacement of epithelial podocyte foot processes
• B Alternating thinning and thickening of the glomerular basement membrane with splitting into a basket-weave pattern ✓
• C Subepithelial electron-dense humps
• D Linear IgG deposition along the glomerular basement membrane

Explanation

Alport syndrome results from mutations affecting type IV collagen (most commonly COL4A5, X-linked). The characteristic ultrastructural lesion is irregular thickening and thinning of the glomerular basement membrane with lamellation and splitting, described as a basket-weave appearance. Foot process effacement is seen in minimal change disease, subepithelial humps in post-infectious glomerulonephritis, and linear IgG in anti-GBM disease. Haematuria with sensorineural deafness and a maternal family history points directly to Alport syndrome.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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