Various Types of Amyloidosis

Various Types of Amyloidosis

The types of systemic amyloidosis differ from each other with regards to the biochemical nature of the amyloid deposit. While some conditions are inherited, the others are acquired. Moreover, some types of systemic amyloidosis share similar features with other diseases. As a result, these types of amyloid are difficult to define during diagnosis, as there is a difference in the treatment:

1. AL (primary) amyloidosis
The acquired plasma cell disorder or primary amyloidosis occurs when the monoclonal immunoglobulin light chain is formed in the bone marrow, which is mostly found in the urine or blood. Primary amyloidosis occurs occasionally with Waldenstrom’s macroglobulinemia, lymphoma, or myeloma. In this type of amyloidosis, the amyloid fibrils are formed of lambda or kappa proteins. Primary amyloidosis is considered to be amyloid because of the light chains. Symptoms of this type of amyloidosis can develop in any organ and can include kidney or heart failure, protein in the urine, swollen tongue or liver, and neuropathy. Treating the condition through chemotherapy would include high doses of medications and stem cell transplantation. This can put the disease of the bone marrow in remission and protect the target organs.

2. AA (secondary) amyloidosis
Inflammatory diseases like granulomatous ileitis, osteomyelitis, Familial Mediterranean Fever (FMF) or rheumatoid arthritis, and chronic infections can cause secondary amyloidosis. Inflammation or infection can cause the elevation of acute-phase protein. This type of amyloidosis is known as secondary amyloidosis as a disease starts in the kidneys. However, it can also affect other organs. The surgical or medical treatment given for the underlying chronic inflammatory disease or infection can be decelerated or the progression of amyloid can be stopped.

3. Familial ATTR amyloidosis
There are some types of amyloidosis that can be inherited. This happens when there is a mutation in the transthyretin gene. As a result, the transthyretin protein is not normal. Since there are abnormal deposits of the transthyretin protein in the form of amyloid fibrils, it gets the name of familial amyloidosis. The symptoms of this disease are mostly cardiomyopathy and neuropathy and can develop in middle-aged people. Over 100 various mutations in the transthyretin are identified and most of them lead to amyloidosis. Familial amyloidosis can also develop with wild forms of unmutated transthyretin protein in older men, resulting in cardiomyopathy. This is also known as senile systemic amyloidosis. The treatments for such a condition include the transplantation of the liver, transthyretin stabilization, or genetically suppressing the production of transthyretin.

There are many more gene mutations that can form proteins which result in amyloidosis. But such cases are rare.