Sara Kline
Period 6
3/25/10

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Chromosomal disorder that damages tiny blood vessels in the kidneys - - these tiny blood vessels are called glomeruli.
The disorder decreases the effectiveness of the kidney’s filtering system which causes build up of fluids and waste in the body.
 The disorder is mild in women and for men the symptoms are more severe and get worse faster.

 The syndrome was named for Dr. Alport
(1927) who noted that a British family who developed renal disease and deafness were mainly men who ended up dying as a result of kidney problems. He also noted that the females were less affected and lived longer.

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Abnormal urine color
Ankle, feel, leg, around the eye swelling
(swelling in general on the body)
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Blood in urine
Decrease or loss in vision (loss is most common in males)
 Sometimes there are no symptoms

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2 nd most common inherited cause of Kidney failure
Occurs when a special type of collagen found in the
Kidney is missing or abnormal
1 in 5,000 children are affected
More common in males due to inheritance
Difficult to detect (except genetic testing in certain families)
The disorder does not affect the phenotype of a person. You cannot tell from the looks of someone whether or not they have the disease with the exception of some swelling.

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No real treatment
To reduce the severity and rapidity one can have restrictions on salt, protein and phosphate in their diet.
Eventually some people with the disorder may need dialysis and/or a kidney transplant
**Stem cell research on a model mouse found that stem cells were able to regenerate damaged cells affected by Alport Syndrome (this could mean some type of better treatment in the future)

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Caused by defects in the chains of type 4-
Collagen
Type 4-Collagen is a family of 6 different proteins: alpha-1 through alpha-6
 Mutations in alpha-3, alpha-4 and alpha-5 chains cause Alport Syndrome

1.
XLAS
2.
ARAS
3.
ADAS

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X-linked
Most common form of the disorder
Type 4 Alpha-5 Collagen Mutations
Accounts for 80-85% of cases
 When the mother is the carrier, the chance of her children getting the disorder is 50% because she has to X chromosomes (which is where the disorder is carried). She has 1 X-chromosome affected, and 1 X-chromosome unaffected.

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Males who carry the mutation will pass on the disease to their daughter because they only have one X-chromosome which is affected by the disorder. They will not pass it to their sons because they give their sons their Y-chromosome which does not carry the disorder.
Daughters who inherit will be carriers because the good X-
Chromosome “masks” the bad X-Chromosome but this does not happen in men because they only have one X-
Chromosome.
Daughters can inherit the disease from their mom or dad and boys can only inherit the disease from their mothers.
10% of children have spontaneous mutation and neither parent carries a mutation.

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Autosomal recessive
10-15% of cases
Mutations in alpha-3 or alpha-4 Collagen
Happens when both copies of a gene are defective
 When each parent carries a mutation in Collagen
Alpha-3 or 4 there is a 25% probability that with every pregnancy the child could have the ARAS form of Alport Syndrome

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Autosomal Dominant
Rare form
5% of cases
Mutations in EITHER alpha-3 or alpha-4 in each cell. Each child of affected parent has
50% chance of inheriting the mutation.

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Alport Syndrome can be Dominant (ADAS) or
Recessive (ARAS) due to the different kinds of inheritance
The disorder is a genetic AND chromosomal disorder.
 Genetic forms are ARAS and ADAS (mentioned above)
 Chromosomal form is XLAS through the X-
Chromosome ONLY.

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 http://www.bbc.co.uk/health/conditions/alport1.
shtml https://www.alportsyndrome.org/alportsub/alport_syndrome_genetics.html
http://www.squidoo.com/alport_syndrome http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?b
ook=gnd&part=alportsyndrome http://www.scielo.br/img/revistas/rboto/v71n6/e n_a20fig04.gif
http://ghr.nlm.nih.gov/condition=alportsyndrom e