A-Z of kidney terms

Our resources and support services aim to empower individuals with knowledge and understanding of Alport syndrome disease, its treatments of and the latest research. If you need assistance beyond what is listed, please reach out to us for support.

This list of terms and definitions has been gathered from several sources in the kidney health community:

https://www.genome.gov/genetics-glossary
https://renalus.com/kidney-101/kidney-glossary/
https://rarediseases.info.nih.gov/diseases?category=&page=1&letter=&search=Fraser
Kidney Health Australia
Alport Syndrome Foundation
KIDGEN Australia
Alport UK
Alport syndrome News

Albumin

This is the major protein in blood. Large amounts of this protein in your urine may be a sign of chronic kidney disease. See albuminuria below.

Albuminuria

A condition in which your urine has more than the normal amounts of albumin. This may be a sign of kidney disease.

Anaemia

A condition in which the number of red blood cells is lower than average. Anaemia reflects low level of haemoglobin in the blood. This results in less oxygen being carried to the body’s cells and can cause reduced energy levels, breathlessness, and feeling of weakness.

Anti-rejection medications

Medication to control your immune system that is needed for as long as your transplanted kidney functions, to reduce the risk of your body rejecting your new kidney.

ACE inhibitors or RAS blockade

This group of medications were originally prescribed to reduce blood pressure. ACE inhibitors also reduce the scarring process in the glomeruli, slowing the progression of kidney disease. It is normally prescribed as a pill to be taken once a day. A blood test is usually performed before starting treatment to record the level of kidney function. Side effects of the treatment are uncommon but may include persistent irritating cough.

ACE inhibitors may be used in conditions where there are high levels of protein in the urine.

In Alport syndrome this group of medications is found to slow the progression of kidney disease.

Angiotensive Receptor Blocker - ARB

Similar to ACE inhibitors, this is another form of medication designed to reduce blood pressure. It is often prescribed if ACE inhibitors have caused side effects such as a persistent cough. Brand names often end in ’sartan’ such as Losartan and Irbesartan. As with ACE inhibitors a blood test is usually performed before starting treatment. ARB medication is used like ACE inhibitors to slow the progression of certain types of kidney disease.

Autosomal Dominant - AD

Autosomal dominant is a pattern of inheritance characteristic of some genetic disorders. “Autosomal” means that the gene in question is located on one of the numbered, or non-sex, chromosomes. “Dominant” means that a single copy of the mutated gene is enough to cause the disorder. A biological child of a person affected by an autosomal dominant condition has a 50% chance of being affected by that condition via inheritance of a dominant allele.

It is important to remember that chance has no memory and the 50% chance of inheriting the altered gene for the condition applied to each child, irrespective of whether or not the parents already have children with, or without the condition.

In autosomal dominant conditions, males and females are affected in roughly equal proportions, and both affected males and females are both able to pass the conditions to their sons or daughters.

Sometimes autosomal dominant conditions can develop for the first time in the affected individual’s family, this is called “de novo”.

Autosomal Recessive. - AR

Autosomal recessive is a pattern of inheritance characteristic of some genetic disorders. “Autosomal” means that the gene in question is located on one of the numbered, or non-sex, chromosomes. “Recessive” means that two copies of the mutated gene (one from each parent) are required to cause the disorder. In a family where both parents are carriers and do not have the disease, roughly a quarter of their biological children will inherit two disease-causing alleles and have the disease.

Automated Peritoneal Dialysis (APD)

A type of dialysis where a special fluid is put into the peritoneal cavity (abdomen) through a soft, plastic tube (catheter) then drained out of the body continuously for a few hours by a machine called a cycler, usually at night.

Blood Pressure

This is the force of blood exerted on the inside walls of blood vessels. Blood pressure is expressed as two numbers. For example, a blood pressure result of 120/80 is said as “120 over 80.” The first number is systolic pressure, or the pressure when the heart pushes blood out into the arteries. The second number is the diastolic pressure, or the pressure when the heart rests.

Carrier

A genetic carrier is an individual who does not show any symptoms of a disease, but “carries” a genetic variant which is associated with disease. The carrier has inherited the variant allele from one parent and a normal allele from the other parent. A carrier can also pass on this genetic variant to their biological children in an autosomal recessive or X-linked manner.

Chromosome

Chromosomes are threadlike structures made of protein and a single molecule of DNA that serve to carry the genomic information from cell to cell. Humans have 22 pairs of numbered chromosomes (autosomes) and one pair of sex chromosomes (XX or XY), for a total of 46. Each pair contains two chromosomes, one coming from each parent, which means that children inherit half of their chromosomes from their biological mother and half from their biological father.

Chronic Kidney Disease - CKD

A progressive reduction in kidney function or kidney damage which is present for at least three months. CKD may develop over many years and may lead to kidney failure, which requires dialysis or a kidney transplant to keep you alive.

Collagen

The main protein in your skin, which gives strength and support for your tendons, cartilage, bone and connective tissue which surround many of your organs.

Creatinine

This is a marker of kidney function, being a waste product of muscular activity. It is usually removed from your blood by your kidneys and passes out in your urine. When your kidneys aren’t working properly, creatinine stays in your blood, and creatinine levels in your blood tests can be higher than normal.

Deletions

This is a type of mutation that involves the loss of one or more nucleotides from a segment of DNA. A deletion can involve the loss of any number of nucleotides, from a single nucleotide to an entire piece of a chromosome.

DNA

Deoxyribonucleic acid (abbreviated DNA) is the molecule that carries genetic information for the development and functioning of an organism. DNA is made of two linked strands that wind around each other to resemble a twisted ladder — a shape known as a double helix.

Dialysis

When the kidneys stop working properly, machines are used to take over some of their function. There are two different kinds of dialysis - haemodialysis and peritoneal dialysis. Both systems control the amount of water and salt in the body and help to remove some of the waste products that our bodies produce. Dialysis can take over the function of the kidneys but does not make them better.

DNA sequencing

DNA sequencing refers to the general laboratory technique for determining the exact sequence of nucleotides, or bases, in a DNA molecule. The sequence of the bases (often referred to by the first letters of their chemical names: A, T, C, and G) encodes the biological information that cells use to develop and operate. Establishing the sequence of DNA is key to understanding the function of genes and other parts of the genome.

Duplication

This refers to a type of mutation in which one or more copies of a DNA segment is produced. This can be as small as a few bases or as large as a major region on a chromosome.

End Stage Renal Disease / End Stage Kidney Disease - ESRD / ESKD

At this stage there is total and permanent kidney failure. When the kidneys fail, the body retains fluid. Harmful wastes build up. A person with ESRD needs treatment with dialysis or transplantation to replace the work of the failed kidneys. (Also see Kidney Failure)

Enzymes

Substances which cause chemical changes to take place in the body.

Erythropoietin - EPO

This is a hormone that is made mostly in the kidneys. The cells that make it are found in the lining of the capillary blood vessels. EPO is released into the blood stream and is picked up by the developing immature red blood cells and allows red cell development to continue. Without EPO, red cell production stops. This way EPO controls the production of red cells and therefore the red cell composition of blood.

In chronic kidney disease the ability of the kidneys to produce EPO falls, and this leads to anaemia.

Estimated Glomerular Filtration Rate - eGFR

This is a blood test result based on creatinine and your age and indicates how well the kidney’s function. The result is like a percentage of your kidney function compared to normal. It helps work out the stage of CKD.

Exome

Each gene has protein-coding regions that are referred to as exons. The human genome contains about 180,000 exons, which are collectively called an exome.

Exon

This is a region of the genome that ends up within an mRNA molecule. Some exons are called “coding” exons containing information to make a protein, and others are “non-coding”.

Gene

The gene is considered the basic unit of inheritance. Genes are passed from parents to their biological children and contain the information needed to code specific proteins which have their individual functions within the body.

Gene Panels

Investigates a defined number of genes, that could include tens to thousands of genes.

Gene Therapy

Gene therapy is a technique that uses a gene(s) to treat a medical disorder. Often, gene therapy works by adding new copies of a gene that is broken, or by replacing a defective or missing gene in a patient’s cells with a healthy version of that gene.

Genetic Counselling

This refers to the guidance relating to genetic disorders that a specialised healthcare professional (genetic counsellor) provides to an individual or family.

Genetic Counsellor

Someone trained to help people understand and made decisions around the medical, psychological, and reproductive effects of your genetic condition. See The Australasian Society of Genetic Counsellors (ASGC) at www.hgsa.org.au/asgc for more information.

Genetic testing

A type of medical test that identifies changes in chromosomes, genes or proteins.

Glomerulus: One of the key structures that make up the nephron which is the filtering unit of the kidney.

Genetics

This is the study of inheritance, including the interplay of genes, DNA variation and their interactions with environmental factors.

Genetic Testing

Genetic testing is the use of a laboratory test to examine an individual’s DNA for variations. In a medical setting, the results of a genetic test can be used to confirm or rule out a suspected genetic disease. Results may also be used to determine the likelihood of parents passing on a genetic mutation to their biological children. Genetic testing may be performed before or after birth.

Genetic testing - PGT

Pre-implantation Genetic Testing (PGT) , sometimes referred to as Pre-implantation genetic diagnosis (PGD), is a sophisticated scientific technique which can be used to test embryos for either a specific known single gene condition or chromosome variation. This enables only chromosomally healthy embryos or those unaffected by a specific disorder to be selected for transfer during an IVF cycle, maximising the chance of a healthy baby.

IVFAustralia offers an internationally recognised pre-implantation genetics program, managed by Australia’s leading pre-implantation genetics laboratory Virtus Diagnostics.

Genomics

This is the study of all the DNA of a person – the genome. Genomics involves identifying all the genes and functional elements in a person’s genome and how they interact.

Genotype

A genotype is an individual’s genetic makeup. It is a scoring of the type of variant present at a given location (i.e., a locus) in the genome. It can be represented by symbols.

Glomerular Basement Membrane GBM

A mesh of proteins found in the kidneys which forms the boundary between the blood and urine. Water and other small molecules are filtered across this membrane from the blood to pass out of the body in the urine.

Glomerular Filtration Rate - GFR

This is a test used to check how well the kidneys are working. Specifically, it estimates how much blood passes through the glomeruli each minute.

Glomerulus (singular) Glomeruli (plural)

Tiny filters found in the outer part of the kidneys which are responsible for filtering the blood stream. Glomeruli are actually tiny arteries folded up into a ball, and tucked inside a capsule which collects the filtered fluid. These microscopic blood vessels are thin walled and very permeable to water and small molecules. They are commonly known as glomerular capillaries. Each capillary is a tiny tube with blood flowing inside it. The wall of the tube has a perforated lining like a colander. This is surrounded by a strong membrane called the Glomerular Basement Membrane.

Haematuria

This is when blood is found in the urine. This occurs when the kidneys aren’t filtering well and red blood cells leak into the urine. Sometimes it can be obvious and the urine changes colour to red or brown (called Macroscopic Haematuria), or it may only be a small amount found when the urine is tested (called Microscopic Haematuria).

Haemodialysis

This is a form of dialysis treatment that takes over the role of the kidneys. Haemodialysis is a way of treating the blood by passing it through an artificial filtering system. Blood is pumped through a filter and cleaned before being returned to the body. Most patients require at least three sessions of haemodialysis a week, with each session lasting around four hours. Treatment usually takes place in hospital but can be set-up at home.

Hypertension

This describes the state of high blood pressure. Blood pressure measures the force of the blood on the walls of the blood vessels. Blood pressure is measured as two numbers: the systolic blood pressure (when the heart contracts), and the diastolic blood pressure (when the heart relaxes). A blood pressure reading of 130/85 means a systolic BP of 130 and a diastolic BP of 85. These two numbers show how hard the heart is working. The harder it is for the blood to flow through the vessels, the higher the blood pressure will be. High blood pressure is one of the major risk factors of kidney disease and kidney failure.

Inherited

This refers to a trait passed on to you by your biological parents. This can include your personality, traits, physical appearance and some health conditions.

In genetics, this term refers to a trait or variant encoded in DNA and passed from biological parent to children during reproduction.

Kidney Biopsy

This is a routine medical test for a wide number of kidney conditions. It is usually done using local anaesthetic, although in younger children sedation or general anaesthesia is often preferred. Mostly biopsies can be done as a day case. Using an imaging technique, usually an ultrasound scan, the doctor steers a needle to the position of one of the kidneys. Thin cores of kidney tissue are taken from the body to be examined under a microscopy to provide a diagnosis.

Kidney Failure or End Stage Kidney Disease (ESKD)

At this stage there is total and permanent kidney failure. When the kidneys fail, the body retains fluid. Harmful wastes build up. A person with ESKD needs treatment with dialysis or transplantation to replace the work of the failed kidneys.

Kidney Function

The amount of work done by the kidneys. A decline in kidney function means the kidneys are not filtering wastes and fluid from the blood as well as they should.

Kidneys

Two bean shaped organs that filter wastes from the blood. The kidneys are located near the middle of the back, one on each side of the spine. Most people have two kidneys, each about the size of an adult fist and weighing 150 grams. Inside each kidney there are about one million tiny units called nephrons. The nephrons are the part of the kidney that filters the blood. Each nephron is made up of a very small filter called a glomerulus. As blood passes through the nephron, water and waste products are removed. Most of the water returns to the blood and the waste products collect in the bladder then leave the body as urine.

Missense Mutation

A missense mutation is a DNA change that results in different amino acids being encoded at a particular position in the resulting protein. Some missense mutations alter the function of the resulting protein.

Mutation

A gene that is faulty and does not work like it should. This can be inherited or caused by environmental factors including diet and chemicals.

Nephron

The tiny parts of the kidney that filter blood to make urine. There are over one million filters in each kidney.

Nephrologist

A medical doctor who specialises in kidney function.

Nocturnal haemodialysis

Where haemodialysis performed at night while you are asleep. This is usually performed in your home.

Nonsense Mutation

A nonsense mutation is a change in the DNA sequence that causes a protein to terminate or end its translation earlier than expected. This change gives rise to a stop codon, which results in the production of a shortened protein that is likely non-functional.

Panel or Gene panel sequencing

Gene panels are collections of genes that have been grouped for testing. This enables DNA sequencing of all the genes with variants known to cause a particular disease, syndrome, or a collection of clinical features.

Pathogenic variant - Pathogenic mutation

This involves a change in the DNA sequence that results in the formation of a non-functioning or faulty gene. It is this gene defect that is known to cause a certain health or developmental condition.

Pedigree

This is a diagram that illustrates the inheritance of a trait or health condition through generations of a family. The pedigree particularly shows the relationships among family members and, when the information is available, indicates which individuals have traits of interest.

Peritoneal Dialysis

This is a form of dialysis treatment that takes over the role of the kidneys. In peritoneal dialysis, fluid is passed in and out of the abdomen through a catheter to remove waste products. The peritoneal dialysis catheter is inserted under a general anaesthetic and dialysis takes place every day in order to be effective. This can take place at home either automatically during the night or manually several times a day following training.

Phenotype

Phenotype refers to an individual’s observable traits, such as height, eye colour and blood type. A person’s phenotype is determined by both their genomic makeup (genotype) and environmental factors.

Point Mutation

This occurs in a genome when a single base pair is added, deleted or changed. While most point mutations are benign, they can also have various functional consequences, including changes in gene expression or alterations in encoded proteins.

Precision / Personalised Medicine

This is an innovative approach that uses information about an individual’s genomic, environmental and lifestyle information to guide decisions related to their medical management. The goal of precision medicine is to provide more a precise approach for the prevention, diagnosis and treatment of disease.

Protein

Proteins are large, complex molecules that play many important roles in the body. They are critical to most of the work done by cells and are required for the structure, function and regulation of the body’s tissues and organs. A protein is made up of one or more long, folded chains of amino acids, whose sequences are determined by the DNA sequence of the protein-encoding gene.

Proteinuria

This is when protein is found in the urine usually because the kidney filters (nephrons) are damaged and leaking. The most common protein found is called albumin (see Albuminuria)

Renal

Of or relating to the kidneys. A renal disease is a disease of the kidneys. Renal failure means the kidneys are damaged.

Risk

In genetics, this refers to the probability that an individual will be affected by a particular genetic disorder. Both a person’s genome and environmental exposures can influence risk. An individual’s risk may be higher because they inherit a genetic variant (orallele) in one gene or a combination of many variants in different genes that increases susceptibility to a particular condition.

Sex Chromosome

This is a type of chromosome involved in sex determination. Humans have two sex chromosomes, X and Y, that in combination determine the sex of an individual. Females have two X chromosomes (XX) in their cells, while males have one X and one Y (XY).

Sex-Linked

This term refers to traits that are influenced by genes carried on the sex chromosomes. This term often refers to traits influenced by genes on the X chromosome, as it contains many more genes than the smaller Y chromosome. Males, who have only a single copy of the X chromosome, are more likely to be affected by a sex-linked disorder than females, who have two copies. In females, the presence of a second, non-mutated copy may cause different, milder, or no symptoms of a sex-linked disorder. (refer to X-linked)

Syndrome

In genetics, related to a group of traits or conditions that tend to occur together and characterise a recognisable disease. Some syndromes have a genetic cause.

Trait

A specific characteristic of an individual. These can be determined by genes, environmental factors or by a combination of both. Traits can be descriptive (i.e. eye colour) or numerical (i.e. blood pressure). A given trait is part of an individual’s overall phenotype.

Transplant

A medical operation involving inserting a donated healthy organ into a recipient in need. Most transplants come from people who have died in hospital on life support machines. They can also come from living people like a close relative or friend. Transplanted organs are carefully chosen to give the best possible chance of success.

Urea

Waste product from the breakdown of protein.

Uraemia

A raised level in your blood of urea and other wastes that are normally removed by your kidneys.

X-Chromosome

The X chromosome is one of the two sex chromosomes that are involved in sex determination. We have two sex chromosomes (X and Y) that in combination determine the sex of an individual. Females have two X chromosomes in their cells (XX), while males have one X and one Y (XY).

X-linked inheritance

This refers to traits that are influenced by genes on the X chromosome. X-linked conditions occur when a pathogenic variant in a gene on the X chromosome leads to disease.

Males, who have only a single copy of the X chromosome, are more likely to be affected by an X-linked disorder than females, who have two copies. In females, the presence of a second, non-mutated copy may cause different, milder, or no symptoms of an X-linked disorder.

Males with X-linked conditions cannot pass their pathogenic variant on to their sons, but they always pass their affected X chromosome to their daughters.

Sons of females with a pathogenic variant on one of their X chromosomes have a 1-in-2 or 50% chance of being affected by the condition.

Y-Chromosome

The Y chromosome is one of the two sex chromosomes that are involved in sex determination. We have two sex chromosomes (X and Y) that in combination determine the sex of an individual. Females have two X chromosomes in their cells (XX), while males have one X and one Y (XY).