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Diagnose This (August 31, 2020)

Alport Syndrome, COL4A5, COL4A3, COL4A4, Alport, X-linked, Hearing loss, GBM multilamellation
What is your diagnosis based on this IF staining pattern in a patient with hematuria and proteinuria?     ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​   ​...

Alport Syndrome

Alport Syndrome
This biopsy from a 22-year-old Hispanic male with a history of hematuria, subnephrotic proteinuria, and chronic kidney disease shows essentially unremarkable glomeruli (Fig 1) with moderate interstitial fibrosis and tubular atrophy, and frequent interstitial foam cells (Fig 2).  Furthermore, electron microscopy shows irregular glomerular basement membranes (GBM) that vary between thick and thin, along with segmental lamellation and diffuse epithelial foot process effacement (Fig 3).  These findings, along with the clinical history are consistent with Alport syndrome. Alport syndrome is a spectrum of diseases affecting the synthesis of type IV collagen, which is the main component of the glomerular basement...

Alport Skin

X-linked Alport syndrome
The most common form of Alport syndrome shows an X-linked dominant inheritance pattern and is caused by mutations in the COL4A5 gene located in the Xq22 region that encodes for the alpha5 chain of type IV collagen. The glomerular basement membrane consists of alpha1, alpha2, alpha3, alpha4 and alpha5 chains, whereas no alpha6 chains are present.  Within the glomerular basement membranes, the alpha3, alpha4, and alpha5 form a network of collagen. Abnormalities, even in one of the chains, can alter this network formation. However, there will be persistence of the alpha1 and alpha2 chains. As a result, diagnosis of Alport is...

Thin GBM Disease

This 41-year-old female presents with microscopy hematuria and subnephrotic proteinuria. The clinical workup is negative for urinary tract infection, nephrolithiasis or other lower urinary tract diseases. A renal biopsy shows essentially unremarkable glomeruli by light microscopy (Fig 1), with scattered red blood cells within the tubular lumens and marked, uniform thinning of the glomerular basement membranes by electron microscopy (Fig 2). These findings are consistent with thin basement membrane disease (TBMD). TBMD affects approximately 1 to 5% of the general population. Mutations in the COL4A3 and COL4A4 genes are identified in up to 40% of affected patients.  Furthermore, TBMD may...