Definition of Hereditary amyloidosis
< b>Hereditary amyloidosis: A familial (inherited) disorder in which protein
deposits (amyloid) accumulate in one or more organ systems in the body.
Hereditary amyloidosis is a relatively uncommon cause of amyloidosis. The more
common forms of amyloidosis are primary an secondary amyloidosis. However, hereditary
amyloidosis is found worldwide. It occurs in families of nearly every ethnic background.
The protein deposits in hereditary amyloidosis are made up of the transthyretin
or TTR protein. The transthyretin protein is manufactured in the liver, and it is
a mutation of this protein that causes hereditary amyloidosis. More than 50 different
mutations in transthyretin are known in connection with this type of amyloidosis.
There are also other proteins which, when mutated, can cause familial amyloidosis,
but these situations are quite rare. (These proteins include apolipoprotein A1,
gelsolin, fibrinogen, and lysozyme.)
In hereditary amyloidosis, the nervous system and gastrointestinal tract are
often involved. This can cause numbness and tingling in the arms and legs, dizziness
upon standing, and diarrhea. Each family with hereditary amyloidosis has its own
pattern of organ involvement and associated symptoms.
The mode of transmission in hereditary amyloidosis is autosomal dominant, which
means that if a male or female has this type of amyloidosis each of their children
has a 1-in-2 (50%) chance of inheriting the same mutation and of having the same
disease. If the child does not inherit the gene, he/she cannot pass it on to future
generations.
The only treatment that offers a potential cure for hereditary amyloidosis is
liver transplantation. Since the transthyretin protein which causes familial amyloidosis
is made in the liver, replacing this organ removes the source of mutant protein
production. A new liver should make entirely normal transthyretin. Whether or not
previously formed amyloid TTR deposits will disappear after liver transplantation
is uncertain and is under study.
Common Misspellings: hereditory amyloidosis
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