A 22-year-old woman evaluated for persistent asymptomatic microscopic hematuria has a family history of isolated hematuria in her father. Hearing, vision, and renal function are normal. Renal biopsy electron microscopy shows uniform attenuation of the lamina densa of the GBM. Which statement is correct?
- A She has thin basement membrane nephropathy, usually due to a heterozygous COL4A3 or COL4A4 mutation, with an excellent prognosis ✓
- B She has Alport syndrome and will develop end-stage kidney disease by age 40
- C She has IgA nephropathy and should receive corticosteroids
- D She has dense deposit disease and requires complement testing
Correct answer: A. She has thin basement membrane nephropathy, usually due to a heterozygous COL4A3 or COL4A4 mutation, with an excellent prognosis
Explanation
Thin basement membrane nephropathy, also called benign familial hematuria, results from heterozygous mutations in COL4B3 or COL4B4 causing diffuse GBM thinning. It produces lifelong isolated hematuria with preserved renal function and no extrarenal features. Alport syndrome, killed by the normal hearing and vision, requires biallelic or X-linked COL4B5 defects and shows basket-weave splitting rather than uniform 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.