LabMed

Alport Syndrome

At a Glance

Alport syndrome is one of the many familial glomerulonephritis (GN). Often, this is seen as a GN (hematuria and proteinuria) in males, but only microscopic hematuria in females (carriers of the genetic risk). It has an age of onset in the late school age to early adolescence but has been identified in the new born male. Like any GN, it will present with blood and protein in the urine with risks of hypertension, edema, and renal insufficiency.

What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

One of the most important tests for Alport syndrome is a family history. If there is a family history of end stage renal disease (ESRD) in males with associated high frequency hearing loss in the early adult years, this is typical. In the male with Alport syndrome, the diagnosis is that of exclusion of other GNs. The usual workup for Alport syndrome is renal function labs, urinalysis, quantitative urine protein, presence of a normal C3, C4, anti-DNA, anti-neutrophil cytoplastic antibody (ANCA), as well as other normal autoantibodies. The confirmation of this syndrome is made on renal biopsy.(Table 1)

Table 1

Test Results Indicative of the Disorder
evidence of high frequency hearing loss in the male evidence of anterior lenticonus on ophthalmologic exam Blood and urine studies can show evidence of normal complete glomeulonephritis but no blood work is diagnostc of this disease. Only a renal biopsy demonstrating the presence of "basket weaving" or "splitting" of the glomerular basement membrane (GBM) is diagnostic.

Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications - OTC drugs or Herbals - that might affect the lab results?

The renal biopsy may not be 100% diagnostic if done "too early" in life. The basement membrane of the glomeruli may be thin in other conditions that may mimic Alport syndrome (e.g., thin basement membrane syndrome, which is not associated with ESRD.

What Lab Results Are Absolutely Confirmatory?

Renal biopsy with antibodies directed to the GBM is absolutely confirmatory of Alport syndrome.

What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?

Diagnosis of Alport syndrome is based on male risk, family history, and exclusion of other familial renal diseases (e.g., polycystic kidney disease, IgA nephropathy, renal stone risk), and it is confirmed by the presence of anterior lenticonus on ophthalmologic exam and findings on renal biopsy.

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