MEDizzy - An asymptomatic 24-year-old woman is found to have

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Urinary System

An asymptomatic 24-year-old woman is found to have microscopic hematuria with a routine urinalysis. Her blood pressure and kidney function are within normal limits, but it is discovered that several members of her family also have asymptomatic microscopic hematuria. Which of the following abnormalities is most likely to be present in this woman?

ExplanationTwo of the most common renal causes of asymptomatic hematuria are IgA nephropathy and thin basement membrane disease (benign familial hematuria). Most patients with thin basement disease do not have symptoms and microscopic hematuria is incidentally found with urinalysis. Blood pressure and kidney function are usually within normal limits, and the prognosis is excellent. Gross hematuria with or without pain is not seen with benign familial hematuria and if present, other causes to be considered include renal stones. Alport syndrome is also in the differential of an individual with microscopic hematuria. This disease is characterized by glomerular injury (resulting in recurrent hematuria), progressive hearing impairment (especially to high frequencies), and ocular abnormalities (such as cataracts and dislocated lens). Alport syndrome is particularly common in the Mormon population (ie, Salt Lake City) and is also called hereditary nephritis, as most cases have an X-linked dominant inheritance pattern. Microscopic sections from the kidney reveal thinning, splitting, and fragmentation of basement membrane and foam cells in glomeruli and tubules. This disease results from defective GBM synthesis, which may cause an absence of the globular region of the alpha 3 chain of type IV collagen. Since this is the region to which the antibodies in Goodpasture syndrome react, sera from a patient with Goodpasture syndrome would fail to react with the glomeruli from a patient with Alport syndrome.