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  #1  
Old 06-09-2011
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Question Confirmatory Test for Alport Syndrome!

Which of the following is the confirmatory test to Alport syndrome?

a) Audiologic assessment
b) CT scan of the head
c) kidney biopsy
d) upper GI endoscopy
e) skin biopsy
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Old 06-09-2011
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C. renal biopsy will show (foam cell )
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c) kidney biopsy
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Quote:
Originally Posted by miss patho View Post
C. renal biopsy will show (foam cell )
nope... the answer is e
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Diagnosis/testing. The diagnosis of collagen IV-related nephropathies rests on (1) history and physical examination, which may include audiologic and ophthalmic evaluation; (2) detailed family history and possibly urinalyses on first- and second-degree relatives; (3) immunohistochemical analysis of basement membrane type IV collagen expression, using skin and/or renal biopsy specimens; and (4) examination of renal biopsy specimens by electron microscopy. With these tools, the diagnosis can be confirmed in most cases. Molecular genetic testing of the type IV collagen genes COL4A3, COL4A4, and COL4A5 is available on a clinical basis.

http://www.ncbi.nlm.nih.gov/books/NBK1207/
so either renal or skin biopsy
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Quote:
Originally Posted by miss patho View Post
so either renal or skin biopsy
Yeah, but skin biopsy is much easier to take than kidney biopsy, that's why it's preferred
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Quote:
Originally Posted by juanpabloq View Post
nope... the answer is e


Alport syndrome is due to mutation in type 4 collagen synthesis affecting kidney, eye and ear. Interestingly-Yes-skin biopsy is useful!

Skin biopsy studied by immunofluorescence is the diagnostic procedure of choice for the X-linked variant of the syndrome.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2464308/

The question is-what about in other variants (autosomal recessive and dominant-although they contribute 20%)?
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Old 06-09-2011
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That can be a tricky question!

Audiometry: All children with a history suggestive of Alport syndrome should undergo high-frequency audiometry to confirm the diagnosis (ie, high-frequency sensorineural hearing loss), as well as periodic monitoring.

Ophthalmologic evaluation: Ophthalmologic examination is important for the early detection and monitoring of anterior lenticonus, perimacular flecks, and other eye lesions.

Percutaneous renal biopsy is an important part of the diagnostic workup. Biopsy may be deferred in a patient with a strong family history of biopsy-proven Alport disease who presents with characteristic clinical features.
The most characteristic finding Is GBM splitting.

Because the a5 chain of type IV collagen is also expressed in the epidermis, immunofluorescence examination of a skin biopsy specimen can be used to establish the diagnosis. Approximately 80% of male patients and 60% of female patients with X-linked Alport syndrome have no a5(IV) collagen in epidermal BM.This approach is especially useful if a kidney biopsy poses an excessive risk, such as in patients with end-stage renal disease (ESRD).

Genetic analyss is the only means for diagnosing the carrier state in asymptomatic female individuals with a family history of X-linked Alport syndrome. Genetic analysis is also the only means for making a prenatal diagnosis. However, screening for randomly distributed mutations within the large collagen-chain genes is tedious, expensive, and time consuming.. In addition, the sensitivity is not high, and the current rate of identification of mutations in Alport kindreds is 50-80% at best.


Electron micrograph from a patient with Alport syndrome revealing the typical splitting and splintering of the glomerular basement membrane.
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Old 06-13-2011
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Quote:
Originally Posted by drmuh View Post
That can be a tricky question!

Audiometry: All children with a history suggestive of Alport syndrome should undergo high-frequency audiometry to confirm the diagnosis (ie, high-frequency sensorineural hearing loss), as well as periodic monitoring.

Ophthalmologic evaluation: Ophthalmologic examination is important for the early detection and monitoring of anterior lenticonus, perimacular flecks, and other eye lesions.

Percutaneous renal biopsy is an important part of the diagnostic workup. Biopsy may be deferred in a patient with a strong family history of biopsy-proven Alport disease who presents with characteristic clinical features.
The most characteristic finding Is GBM splitting.

Because the a5 chain of type IV collagen is also expressed in the epidermis, immunofluorescence examination of a skin biopsy specimen can be used to establish the diagnosis. Approximately 80% of male patients and 60% of female patients with X-linked Alport syndrome have no a5(IV) collagen in epidermal BM.This approach is especially useful if a kidney biopsy poses an excessive risk, such as in patients with end-stage renal disease (ESRD).

Genetic analyss is the only means for diagnosing the carrier state in asymptomatic female individuals with a family history of X-linked Alport syndrome. Genetic analysis is also the only means for making a prenatal diagnosis. However, screening for randomly distributed mutations within the large collagen-chain genes is tedious, expensive, and time consuming.. In addition, the sensitivity is not high, and the current rate of identification of mutations in Alport kindreds is 50-80% at bes


Electron micrograph from a patient with Alport syndrome revealing the typical splitting and splintering of the glomerular basement membrane.
Kidney bx. I guess.
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Quote:
Originally Posted by surg View Post
so the confirmatory test will be genetic testing and the best confirmatory test among the options could be renal biopsy?!

lathibv: skin biopsy is easy means it can be done primarily, but it is not 100% sensitive as mentioned by 1TA2B ,so the absence of disease requires rena biopsy?!

am i thinking right???

p.s: im a medical student who just now realised that i ve to study, so please put up with my doubts till im on the track
I would go with renal biopsy as confirmation in non-x linked Alport!

Juanpablog-That would be helpful if you can share the explanation!

Thanks
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Old 06-16-2011
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Quote:
Originally Posted by 1TA2B View Post
I would go with renal biopsy as confirmation in non-x linked Alport!

Juanpablog-That would be helpful if you can share the explanation!

Thanks
The explanation is the following:

Skin biopsy is the preferred and always initial confirmatory test, patients with Alport syndrome have a defect in collagen type IV which will show also on skin. If the skin biopsy is equivocal and you have doubts then you proceed with the kidney biopsy. So in conclusion, skin biopsy is preferred because is less invasive!
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Old 06-28-2011
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I would agree with skin biosy (a non ivasive one which is more available than kidney Bx that require much more skills). And there is many good reasons for that.


Most of Alport's syndrome belong to The 3 genetic forms :
  • XLAS (X-linked Alport Syndrome) – The most common form that accounts for 80% to 85% of the cases and results from mutations of the alpha-5 chain type IV collagen (gene COL4A5)
  • ARAS (autosomal recessive Alport Syndrome) – This form accounts for 10% to 15% of the cases and is caused by mutations in the alpha-3 or alpha-4 chains (genes COL4A3 or COL4A4)
  • ADAS (autosomal dominant Alport Syndrome) – Rare form that accounts for about 5% of the cases and is caused by mutations in the alpha-3 or alpha-4 chains (genes COL4A3 or COL4A4).
And at the skin, The type IV collagen alpha-5 chain (COL4A5) is normally present in the skin and a biopsy of the skin can be tested for the presence or absence of this collagen chain. A skin biopsy is less invasive than a kidney biopsy and can be done in a doctor’s office so this should be considered first for diagnosis of suspected XLAS patients.

In conclusion, if we suspect the presence of x-link disease, we should do skin Bx first and then later with kidney bx.

http://www.alportsyndrome.org/what-i...ome-diagnosis/

God blesses everyone
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