ALPORT SYNDROME Flashcards
What is the collagen affected in Alport syndrome?
Type 4 collagen (α3α4α5)
What are the 3 characteristic findings in Alport Syndrome?
- KIDNEYS: inevitable progression to ESKD
- EARS: deafness
- EYES: ocular abnormalities
Alport syndrome usually manifests in which 2 population groups?
- CHILDREN
- YOUNG ADULTS
What is the difference in disease manifestations in patients with Alport syndrome in males vs females?
MALES: slow progression to ESKD
FEMALES: mild disease
Where is the site of aural lesion in Alport Syndrome?
COCHLEA
What is pathognomonic of Alport syndrome?
ANTERIOR LENTICONUS
What is the condition wherein there is protrusion of the central portion of the lens into the anterior capsule?
ANTERIOR LENTICONUS
What is a variant of Alport syndrome, which includes the association of hereditary nephritis with thrombocytopathia (megathrombocytopenia)
EPSTEIN SYNDROME
The diagnosis of Alport Syndrome is based on what histologic imaging?
EM
What are the 2 special stains that reveal thickening and lamellation of the GBM?
- JONES METHANAMINE SILVER STAIN
- PAS
How many types of Type 4 Collagen?
6 types
Which chain of type 4 collagen is found in all renal basement membranes?
Type IV α1, α1, α2
What chain of the type 4 collagen are present in mature GBM and distal tubular basement membrane (TBM)?
Type IV α3, α4, α5
What chain of type 4 collagen is found in Bowman’s capsule, collecting duct TBM, and in epidermal basement membrane?
Type IV α5, α5, α6
Absence of what kind of chain staining in skin biopsies is highly specific for the diagnosis of X-linked Alport syndrome?
α5
What is the earliest change in young males with Alport syndrome in EM?
Thinning of the GBM
What is the cardinal ultrastructural abnormality in EM in Alport Syndrome?
variable thickening, thinning, basket weaving, and lamellation of the GBM
In males, what is the percentage increase in the number of glomeruli showing lamellation by age 30 years?
90%
What are three genetic forms of hereditary nephritis?
- X-LINKED
- AUTOSOMAL
- DIGENIC
What is the most common pattern of inheritance in hereditaty nephritis?
X-LINKED
What type of collagen defect causes Hereditary nephritis?
TYPE 4
Mutations in this gene are responsible for the more frequent X-linked form of hereditary nephritis
COL4A5 gene
What gene encodes the α5 subunit of collagen type IV?
COL4A5 gene
Is there a proven therapy for Alport syndrome?
NONE
