Prognosis varies with the type of amyloidosis. Prognosis for untreated AL amyloidosis is poor with median survival of one to two years. More specifically, AL amyloidosis can be classified as stage I, II or III based on cardiac biomarkers like troponin and BNP. Survival diminishes with increasing stage, with estimated survival of 26, 11 and 3.5 months at stages I, II and III, respectively.

Outcomes in a person with AA amyloidosis depend on the underlying disease and correlate with the concentration of serum amyloid A protein.

People with ATTR have better prognosis and may survive for over a decade.

Senile systemic amyloidosis was determined to be the primary cause of death for 70% of people over 110 who have been autopsied.

The disorder typically affects the heart and its prevalence increases in older age groups. Men are affected much more frequently than women. In fact, up to 25% of men over the age of 80 may have evidence of WTTA.

Patients often present with increased thickness of the wall of the main heart chamber, the left ventricle. People affected by WTT amyloidosis are likely to have required a pacemaker before diagnosis and have a high incidence of a partial electrical blockage of the heart, known as left bundle branch block. Low ECG signals such as QRS complexes are widely considered a marker of cardiac amyloidosis.

A much better survival has been reported for patients with WTTA as opposed to cardiac AL amyloidosis .

The three most common forms of amyloidosis are AL, AA, and ATTR amyloidoses. The median age at diagnosis is 64.

In the western hemisphere, AL is the most prevalent, comprising 90% of cases. In the United States it's estimated that there are 1,275 to 3,200 new cases of AL amyloidoses a year.

AA amyloidoses is the most common form in developing countries and can complicate longstanding infections with tuberculosis, osteomyleitis, and bronchiectesis. In the west, AA is more likely to occur from autoimmune inflammatory states. The most common causes of AA amyloidosis in the West are rheumatoid arthritis, inflammatory bowel disease, psoriasis, and familial Mediterranean fever.

People undergoing long term hemodialysis (14–15 years) can develop amyloidosis from accumulation of light chains of the HLA 1 complex which is normally filtered out by the kidneys.

Senile amyloidosis resulting from deposition of normal transthyretin, mainly in the heart, is found in 10–36% of people over 80.

Median survival for patients diagnosed with AL amyloidosis was 13 months in the early 1990s, but had improved to c. 40 months a decade later.

Wild-type transthyretin amyloid accumulates mainly in the heart, where it causes stiffness and often thickening of its walls, leading consequently to shortness of breath and intolerance to exercise, called diastolic dysfunction. Excessively slow heart rate can also occur, such as in sick sinus syndrome, with ensuing fatigue and dizziness. Wild-type transthyretin deposition is also a common cause of carpal tunnel syndrome in elderly men, which may cause pain, tingling and loss of sensation in the hands. Some patients may develop carpal tunnel syndrome as an initial symptom of wild-type transthyretin amyloid.

There appears to be an increase in the risk for developing hematuria or blood in the urine due to urological lesions.

AL amyloidosis is a rare disease; only 1200 to 3200 new cases are reported each year in the United States. Two thirds of patients with AL amyloidosis are male and less than 5% of patients are under 40 years of age.

AA amyloidosis is a complication of a number of inflammatory diseases and infections, although only a small portion of patients with these conditions will go on to develop AA amyloidosis. A natural history study of AA amyloidosis patients published in the New England Journal of Medicine reported a number of conditions associated with AA amyloidosis. The most common presentation of AA amyloidosis is renal in nature, including proteinuria, nephrotic syndrome and progressive development of renal insufficiency leading to End Stage Renal Disease (ESRD) and need for renal replacement therapy (e.g. dialysis or renal transplantation).

- Autoimmune diseases

- Rheumatoid arthritis

- Ankylosing spondylitis

- Crohn's disease and ulcerative colitis

- Chronic infections

- Tuberculosis

- Bronchiectasis

- Chronic osteomyelitis

- Autoinflammatory diseases

- Familial Mediterranean fever (FMF)

- Muckle–Wells syndrome (MWS)

- Cancer

- Hodgkin's lymphoma

- Renal cell carcinoma

- Chronic foreign body reaction

- HIV/AIDS

- Silicone-induced granulomatous reaction

Although not based on a human clinical trial, the only currently accepted disease-modifying therapeutic strategy available for familial amyloid cardiomyopathy is a combined liver and heart transplant. Treatments aimed at symptom relief are available, and include diuretics, pacemakers, and arrhythmia management. Thus, Senile systemic amyloidosis and familial amyloid polyneuropathy are often treatable diseases that are misdiagnosed.

In 2013, the European Medicines Agency approved the drug tafamidis (Vyndaqel) to slow the progression of familial amyloid polyneuropathy, a related disease caused by TTR aggregation that first presents as an autonomic and/or peripheral neuropathy (later progressing to a cardiomyopathy).

There is evidence that eating amyloid fibers may lead to amyloidosis. This evidence is based on studies in cattle, chickens, mice, and cheetahs. Thus, in a sense, SAA amyloidosis may be considered a contagious disease, although whether this occurs or is important in the development of naturally occurring amyloidosis remains unknown. Nevertheless, because amyloid fibers can be detected in muscle in low amounts, it raises some concern about whether people could develop amyloidosis as a result of ingesting meat from an animal with the disease.

Most individuals diagnosed with LECT2 amyloidosis in the United States (88%) are of Mexican descent and reside in Southwest region of the United States (New Mexico, Arizona, far Western Texas). Other groups with higher incidence rates of the disorder include First Nation Peoples in Canada, Punjabis, South Asians, Sudanese, Native Americans, and Egyptians. In Egyptians, for example, LECT2 is second most common cause of renal amyloidosis, accounting for nearly 31% of all cases.

ALECT2 amyloidosis is generally diagnosed in individuals between the ages 40 and 90, with a mean age of 67 years old. The disorder commonly presents with renal disease that in general is advanced or at an end stage. Associated signs and symptoms of their renal disease may include fatigue, dehydration, blood in urine, and/or other evidence for the presence of the nephrotic syndrome or renal failure. Further studies may find that these individuals have histological or other evidence of LECT2 amyloid deposition in the liver, lung, spleen, kidney, and/or adrenal glands but nonetheless they rarely show any symptoms or signs attributable to dysfunction in these organs. Unlike many other forms of systemic amyloidosis, LECT2 deposition has not been reported to be deposited in the myocardium or brain of affected individuals. Thus, LECT2 amyloidosis, while classified as a form of systemic amyloidosis, almost exclusively manifests clinically as renal amyloidosis. No familial link has been found in the disorder although there have been several cases described among siblings.

LECT2 Amyloidosis is a form of amyloidosis caused by the LECT2 protein. It was found to be the third most common (~3% of total) cause of amyloidosis in a set of more than 4,000 individuals studied at the Mayo Clinic; the first and second most common forms the disorder were AL amyloidosis and AA amyloidosis, respectively. Amyloidosis is a disorder in which the abnormal deposition of a protein in organs and/or tissues gradually leads to organ failure and/or tissue injury.

Although more than 30 different proteins can cause amyloidosis, the disorder caused by LECT2 is distinctive in three ways. First, it has an unusually high incidence in certain ethnic populations. Second, it is a systemic form of amyloidosis (i.e. amyloid deposited in multiple organs), as opposed to a localized form (amyloid deposits limited to a single organ) but nonetheless injures the kidney without or rarely injuring the other organs in which it is deposited. Third, LECT2 amyloidosis is diagnosed almost exclusively in elderly individuals.

Given its relatively recent discovery, exceptionally strong ethnic bias, limitation to causing kidney disease, and restriction to elderly individuals, LECT2 amyloidosis appears at present to be an under-recognized cause of chronic kidney disease particularly in the ethnic groups that exhibit a high incidence of the disorer.

Haemodialysis-associated amyloidosis is a form of systemic amyloidosis associated with chronic kidney failure.

Familial Amyloid Cardiomyopathy (FAC), or Transthyretin Amyloid Cardiomyopathy (ATTR-CM) results from the aggregation and deposition of mutant and wild-type transthyretin (TTR) protein in the heart. TTR amyloid fibrils infiltrate the myocardium, leading to diastolic dysfunction from restrictive cardiomyopathy, and eventual heart failure. Both mutant and wild-type transthyretin comprise the aggregates because the TTR blood protein is a tetramer composed of mutant and wild-type TTR subunits in heterozygotes. Several mutations in TTR are associated with FAC, including V122I, V20I, P24S, A45T, Gly47Val, Glu51Gly, I68L, Gln92Lys, and L111M. One common mutation (V122I), which is a substitution of isoleucine for valine at position 122, occurs with high frequency in African-Americans, with a prevalence of approximately 3.5%. FAC is clinically similar to senile systemic amyloidosis, in which cardiomyopathy results from the aggregation of wild-type transthyretin exclusively.

The median time to progression to end stage renal disease is 2.7 years. After 5 years, about 37% of patients with LCDD are alive and do not have end stage renal disease.

Long-term haemodialysis results in a gradual accumulation of β microglobulin, a serum protein, in the blood. It accumulates because it is unable to cross the dialysis filter.

Affected individuals usually present after 5 years of dialysis rarely before that. The tendency of haemodialysis-associated amyloidosis is to be articular in general affecting the joints.

Liver transplantation has proven to be effective for ATTR familial amyloidosis due to Val30Met mutation.

Alternatively, a European Medicines Agency approved drug Tafamidis or Vyndaqel now exists which stabilizes transthyretin tetramers comprising wild type and different mutant subunits against amyloidogenesis halting the progression of peripheral neuropathy and autonomic nervous system dysfunction.

Currently there are two ongoing clinical trials undergoing recruitment in the United States and worldwide to evaluate investigational medicines that could possibly treat TTR.

The familial amyloid neuropathies (or familial amyloidotic neuropathies, neuropathic heredofamilial amyloidosis, familial amyloid polyneuropathy) are a rare group of autosomal dominant diseases wherein the autonomic nervous system and/or other nerves are compromised by protein aggregation and/or amyloid fibril formation.

Organ-limited amyloidosis is a category of amyloidosis where the distribution can be associated primarily with a single organ. It is contrasted to systemic amyloidosis, and it can be caused by several different types of amyloid.

In almost all of the organ-specific pathologies, there is significant debate as to whether the amyloid plaques are the causal agent of the disease or instead a downstream consequence of a common idiopathic agent. The associated proteins are indicated in parentheses.

Primary systemic amyloidosis (AL amyloidosis or just primary amyloidosis) is a disease that involves the mesenchymal tissue, the tongue, heart, gastrointestinal tract, and skin.

Familial renal amyloidosis (or familial visceral amyloidosis, or hereditary amyloid nephropathy) is a form of amyloidosis primarily presenting in the kidney.

It is associated most commonly with congenital mutations in the fibrinogen alpha chain and classified as a dysfibrinogenemia (see Hereditary Fibrinogen Aα-Chain Amyloidosis). and, less commonly, with congenital mutations in apolipoprotein A1 and lysozyme.

It is also known as "Ostertag" type, after B. Ostertag, who characterized it in 1932 and 1950.

The disease mechanism (pathophysiology) of RS3PE remains unknown. One study suggested a possible role for vascular endothelial growth factor. A study using magnetic resonance imaging found that tenosynovitis of the extensors of the hands and feet is the major contributor to edema.

The pathogenesis of this disease is unclear. Arteriosclerosis obliterans has been postulated as the cause, along with errors of the clotting and fibrinolytic pathways such as antiphospholipid syndrome.

This disease is endemic in Portuguese locations Póvoa de Varzim and Vila do Conde (Caxinas), with more than 1000 affected people, coming from about 500 families, where 70% of the people develop the illness. ll the analysed Portuguese families presented the same haplotype (haplotype I) associated with the Met 30 mutation. In northern Sweden, more specifically Piteå, Skellefteå and Umeå, 1.5% of the population has the mutated gene. There are many other populations in the world who exhibit the illness after having developed it independently.

Secondary systemic amyloidosis is a condition that involves the adrenal gland, liver, spleen, and kidney as a result of amyloid deposition due to a chronic disease such as Behçet's disease, ulcerative colitis, etc.

RS3PE is a constellation of symptoms that can be caused by many other conditions. Since there is no definitive diagnostic test, other conditions have to be ruled out before this rare condition can be diagnosed.

The main differential diagnosis is polymyalgia rheumatica (PMR), although pain, stiffness and weakness at the level of the shoulders and pelvic girdle with associated systemic symptoms (fever, malaise, fatigue, weight loss) is more typical of PMR. Prospective studies have found a subgroup of PMR patients with hand edema, as well as other similarities. Thus, RS3PE has been proposed as a condition related to PMR or even that they are both part of the same disorder. However, PMR typically requires protracted courses of steroids, whereas corticosteroids can be tapered more quickly with persisting remission in RS3PE.

Other rheumatological disorders that can cause the features typical for RS3PE include late onset (seronegative) rheumatoid arthritis, acute sarcoidosis, ankylosing spondylitis and other spondyloarthropathies such as psoriatic arthropathy, mixed connective tissue disease, chondrocalcinosis and arthropathy due to amyloidosis.

RS3PE has been documented in patients with cancers (Non-Hodgkin's lymphoma, gastric cancer, pancreatic cancer, lung cancer, breast cancer, colon cancer, prostate cancer and bladder cancer, among others), in whom it might represent a paraneoplastic manifestation.

Other underlying disorders include vasculitides such as polyarteritis nodosa.

Other causes of edema include heart failure, hypoalbuminemia, nephrotic syndrome and venous stasis. The key distinguishing feature is that these conditions don't tend to manifest with pitting edema at the back of the hands.