A 22-year-old woman is found to have persistent microscopic hematuria on routine testing. She has no proteinuria, normal blood pressure, and normal creatinine. Her father has had isolated hematuria for decades without renal failure. Audiometry and eye examination are normal. Renal biopsy electron microscopy shows uniform thinning of the glomerular basement membrane. The most likely diagnosis is:

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

Explanation

Benign familial hematuria results from heterozygous mutations in COL4A3 or COL4A4, producing uniform GBM thinning with isolated hematuria, preserved hearing, normal eyes, and no progression to renal failure. Alport syndrome, caused usually by hemizygous COL4A5 mutation, shows the basket-weave splitting on EM with sensorineural deafness and ocular lesions, so the normal audiometry kills that distractor. IgA nephropathy would show mesangial IgA deposits rather than pure ultrastructural thinning.

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.