Simple Glossary

[Last updated February 28, 2015)]
[Page initially created May 1, 2013]

This page is a simple glossary of mostly medical terms that are used in the medical literature related to amyloidosis, and fibrinogen amyloidosis in particular. I call this a simple glossary because the intent is not to provide an accurate medical definition of these terms, since medical definitions can easily be found elsewhere on the internet. (Keep in mind that I am not a medical professional, so some of these definitions below could be completely wrong or misleading.)

My goal here is to provide very simple definitions to: A) Help you understand the articles in medical journals, and B) Help you explain things to friends and family without giving them a lesson in medical terminology first.

AA Amyloidosis: A type of amyloidosis that is secondary to some other condition or disease in the body. Often referred to as secondary amyloidosis.

AL Amyloidosis: Also known as primary amyloidosis. This form of amyloidosis is the most commonly diagnosed. It is not hereditary and the cause is unknown.

Amyloidosis: Think of amyloidosis as a disease where the body generates little of pieces of plastic that float around in the blood. The body doesn't know what to do with these little pieces of plastic or how to get rid of them, so they end up accumulating in various organs, essentially gumming up the works. These little pieces of "plastic" are actually abnormal proteins. (The word "protein" in this case does not refer to the protein found in various foods, but rather to various types of molecules that make up any living organism.)

ATTR: A type of familial amyloidosis caused by a mutation in the transthyretin gene.

Autosomal Dominant: If a genetic disease is inherited in an autosomal dominant fashion, it means you only need to get the abnormal gene from one parent in order to inherit the disease. Fibrinogen amyloidosis mutations are autosomal dominant. (Autosomal recessive means the abnormal gene must be inherited from both parents.)

Azotemia: Kidney issues characterized by elevated BUN (blood urea nitrogen) and serum creatinine levels. This term is more specific than nephrotic syndrome.

Bone Marrow Biopsy: A diagnostic test for amyloidosis. The bone marrow biopsy of a fibrinogen amyloidosis patient will typically not show any signs of amyloidosis, since the liver is the "factory," not the bone marrow.

Buttonhole Technique: Using the exact same needle location for hemodialysis access every time. A tunnel of scar tissue is formed, which significantly reduces the pain of needle insertion.

Congo Red, or Congo Red Staining: Congo Red is a substance used when analyzing tissue biopsies to detect the presence of amyloidosis (more specifically, amyloid fibrils). 

Coumadin: An anti-coagulant sometimes used to prevent clotting during hemodialysis sessions, especially in patients who are allergic to heparin.

CPHPC: A drug that has shown some effectiveness in enabling the body to eliminate amyloid deposits. As of 2013 it is only available through clinical trials in England.

Creatinine: Creatinine is a breakdown product of creatine, an important part of muscle. Creatinine is constantly produced by the body and appears in the blood, then gets filtered out by the kidneys. A serum creatinine test measures the level of creatinine in the blood. As the kidneys fail to filter creatinine out of the blood, the serum creatinine level increases.

Dialysis: A process for removing waste and excess water from the blood, which is usually a function of the kidneys. The two main types of dialysis are hemodialysis and peritoneal dialysis.

Domino Liver Transplant: A domino liver transplant is when a liver from a deceased person (person A) is transplanted into a recipient (person B), and then the liver removed from that recipient (person B) is transplanted into a second recipient (person C). Liver A goes to B, liver B goes to C, liver C is disposed of. A fibrinogen amyloidosis patient may be a good candidate for person B of a domino liver transplant because his or her liver is perfectly fine in all aspects other than producing amyloids, so an elderly patient waiting on a liver transplant would gladly take that liver to extend their life by 10 to 20 years, since they would likely be unaffected by the amyloids.

Doxycycline: An antibiotic, sometimes used by people who are allergic to penicillin, that has shown some effectiveness in breaking down amyloid deposits in mice. As of 2013 there is a clinical trial through Boston University testing its effectiveness against amyloid deposits in humans.

Dry Weight: The weight of a hemodialysis patient without any excess fluid. Ideally this is what a dialysis patient weighs immediately after a hemodialysis session.

eGFR: See GFR.

Familial: Hereditary

Fibril: A threadlike fiber. Amyloid deposits are often described as consisting of protein fibrils, which means they are like short pieces of thread instead of small chunks of protein.

Fibrinogen: A substance in the blood that is part of the blood clotting process. Most fibrinogen amyloidosis mutations, including the most common one (Glu526Val), do not affect blood clotting.

Fibrinogen Amyloidosis: A disease caused by a genetic mutation in the fibrinogen gene. It typically affects the kidneys first, with the first symptoms usually appearing well after a person reaches the age of 40. Some people with the mutation never develop symptoms.

Fistula: Also known as an arteriovenous fistula (AV fistula). A connection between an artery and a vein that is surgically created as an access for hemodialysis.

GFR: Glomerular Filtration Rate. (same thing as eGFR) A test that estimates how much blood is flowing through the kidneys, based on your serum creatinine level and factors such as your age, gender, height, weight and race. As the kidneys fail, this number will decrease. This test is important in the early detection of kidney issues, especially if fibrinogen amyloidosis is a possibility.

Glomerular: Having to do with the glomerulus (see below).

Glomeruli: Plural of glomerulus.

Glomerulus: Part of the kidneys. Think of it as the first stage of what goes on in the kidney. The glomerulus is a cluster of small blood vessels in the kidney where impurities and water are initially filtered out. The glomerulus is part of the nephron.

Hematologist: A doctor specializing in hematology, the study of blood and blood diseases.

Hemodialysis: A method of dialysis where the patient's blood is pumped through a filter to remove waste and excess water, then returned to the patient's body.

Heparin: An anti-coagulant typically used to prevent clotting during hemodialysis sessions. See also: Coumadin.

Hepatic: Having to do with the liver.

Hepatologist: A liver doctor.

Hepatorenal: Relating to the liver and the kidney. A hepatorenal transplant is when a patient receives a combined liver and kidney transplant.

Heterozygous: Having one normal copy of a gene and one abnormal (mutated) copy. Most patients with fibrinogen amyloidosis are heterozygous, indicating they inherited the mutation from one parent. See also: Homozygous.

Homozygous: Having two abnormal (mutated) copies of a gene. This condition indicates that the mutated gene was inherited from both parents. See also: Heterozygous.

Kindred: A group of people who are biologically related. This term is more accurate than "family" since a family includes people related by marriage.

Nephrologist: Kidney doctor. 

Nephron: The basic structural and functional unit of the kidney. A normal human kidney has about a million nephrons. 

Nephropathy: Any damage to or disease of a kidney. Sometimes used interchangeably with nephrotic syndrome.

Nephrotic Syndrome: Kidney disease that typically includes proteinuria and edema.

Neuropathy: A disease of the nervous system. The most common form of familial amyloidosis, ATTR, typically causes neuropathy. Fibrinogen amyloidosis rarely causes neuropathy, so it is considered nonneuropathic.

Oncologist: A doctor specializing in oncology, the branch of medicine that deals with cancer.

Orthotopic: Occurring at the normal place in the body. A liver transplant is typically orthotopic because the old liver is removed and the new liver is put in its place. Kidney transplants are typically not orthotopic because the old kidneys are left in place and the new kidney is placed below them.

Pathogenesis: This word appears frequently in the medical literature. The pathogenesis of a disease is simply a description of its origin and development.

Penetrance: How likely a person with a genetic mutation is to develop symptoms associated with that mutation. If a disease has 100% penetrance that means everyone with the mutation has symptoms of the disease. The penetrance  of fibrinogen amyloidosis is not 100%, and is often described as low, meaning people with the mutation often do not develop clinically significant symptoms.

Peritoneal Dialysis: A method of dialysis that uses fluid exchanges in the abdomen to extract impurities from the body when the kidneys are no longer able to function properly.

Precursor Protein: In the context of amyloidosis, a precursor protein is a protein that is known to contribute to the buildup of amyloid deposits. Fibrinogen is one of many precursor proteins. Here the word "protein" is not referring to dietary protein, but rather to the various organic molecules manufactured by the body.

Primary Amyloidosis: Also known as AL amyloidosis. This form of amyloidosis is the most commonly diagnosed. It is not hereditary and the cause is unknown.

Proband: The first person in a family diagnosed with a hereditary disease. Also called the propositus.

Propositus: The first person in a family diagnosed with a hereditary disease. Also called the proband.

Proteinuria: When excess protein is in the urine.

Renal: Having to do with the kidneys

SAP Scintigraphy: An imaging technique that shows amyloid deposits in the body. Think of it as an amyloid x-ray, or an amyloid CT scan. Used at National Amyloidosis Centre in the UK.

Scintigraphy: See SAP Scintigraphy.

Secondary Amyloidosis: A type of amyloidosis that is secondary to some other condition or disease in the body. Officially referred to as AA amyloidosis.

Serum Creatinine: A test that measures the level of creatinine in the blood. This test is important in the early detection of kidney issues, especially if fibrinogen amyloidosis is a possibility.

Stem Cell Transplant: One method of treating AL amyloidosis. Not applicable to any of the familial types of amyloidosis.

1 comment:

  1. As ever David, your information is both accurate and helpful. Thanks for being on the case