Amyloidosis
Amyloidosis is a group of diseases in which abnormal proteins, known as amyloid fibrils, build up in tissue.[4] There are several types with varying symptoms; signs and symptoms may include diarrhea, weight loss, feeling tired, enlargement of the tongue, bleeding, numbness, feeling faint with standing, swelling of the legs, or enlargement of the spleen.[2]
There are about 30 different types of amyloidosis, each due to a specific protein misfolding.[5] Some are genetic while others are acquired.[3] They are grouped into localized forms, and systemic ones.[2] The four most common types of systemic amyloidosis are light chain (AL), inflammation (AA), dialysis-related (Aβ2M), and hereditary and old age (ATTR and familial amyloid polyneuropathy[6]).[2]
Diagnosis may be suspected when protein is found in the urine, organ enlargement is present, or problems are found with multiple peripheral nerves and it is unclear why.[2] Diagnosis is confirmed by tissue biopsy.[2] Due to the variable presentation, a diagnosis can often take some time to reach.[3]
Treatment is geared towards decreasing the amount of the involved protein.[2] This may sometimes be achieved by determining and treating the underlying cause.[2] AL amyloidosis occurs in about 3–13 per million people per year and AA amyloidosis in about 2 per million people per year.[2] The usual age of onset of these two types is 55 to 60 years old.[2] Without treatment, life expectancy is between six months and four years.[2] In the developed world about 1 per 1,000 people die annually from amyloidosis.[3] Amyloidosis has been described since at least 1639.[2]
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