A 22-year-old man has persistent microscopic hematuria discovered on a routine checkup. Renal function is normal, there is no proteinuria, and family history reveals benign hematuria in his father. Electron microscopy shows uniform thinning of the glomerular basement membrane. What is the diagnosis?

• A Alport syndrome
• B IgA nephropathy
• C Thin basement membrane lesion (benign familial hematuria) ✓
• D C3 glomerulopathy

Explanation

Thin basement membrane lesion is usually autosomal dominant, caused by heterozygous mutations in COL4A3 or COL4A4, and presents as isolated hematuria with normal renal function, no proteinuria and uniformly thinned GBM on electron microscopy. It carries an excellent long-term prognosis. Alport syndrome differs by showing GBM splitting and basket-weave appearance, sensorineural deafness and ocular changes. IgA nephropathy would show mesangial IgA deposits on immunofluorescence.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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