Term Glossary

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Adenine: One of the four nucleotide bases that form DNA (the others are cytosine, guanine and thymine) which stores genetic information of all known living organisms

AGT (alanine-glyoxylate aminotransferase): A liver enzyme. Low levels of this enzyme create elevated levels of oxalate and this causes PH Type I.

Allopurinol: Medication used to treat APRT deficiency

Amino aciduria: Presence of amino acids in the urine. Normally amino acids are fully reabsorbed form the urine.

Analysis of kidney stones: Testing to elucidate the ingredients of kidney stones

Arginine: Non-essential amino acid (made only by the urea cycle)

Asymptomatic: No symptoms present

Autosomal: An autosome is a chromosome that is not a sex chromosome. The term autosomal refers to a hereditary condition that is transmitted with an autosome.

Autosomal recessive: In an autosomal recessive disease (like PH) the child inherits an abnormal gene from each parent. Each parent has one normal gene and one abnormal gene and doesn’t show signs of the disease. It takes 2 copies of an abnormal gene to cause PH.


C.E. Dent: Physician at University College London who initially described Dent disease in the 1950s

Citrate: Small molecule found in fruits and vegetables that can also be given as a medication in the form of potassium citrate. Higher levels of citrate in the urine can help to prevent kidney stones.

CLCN5: Name of the gene that that is mutated in most cases of Dent disease. It encodes a protein that acts as a chloride channel in kidney cells.

Crystalluria: Crystals in the urine

Defective gene: Gene that is not working properly (damaged gene)

Deficiency: Lack or shortage of a substance or an enzyme

Dialysis: A medical procedure used to replace kidney function in patients with kidney failure

Disorder: Disease or condition

2,8-dihydroxyadenine: A substance made in the human body from adenine, closely related to uric acid and xanthine. Under abnormal circumstances 2,8,dihydroxyadenine can be found in large amounts in human urine.

Enzyme: A protein that controls chemical reactions involved in metabolism

ESRD: End Stage Renal Disease; kidney failure


Genetic testing: Blood test to identify DNA mutations or changes that cause specific diseases

Genetics: The science of heredity in living organisms

Glycosuria: Presence of glucose in the urine. Normally glucose is fully reabsorbed form the urine.

GRHPR: Glyoxylate reductase (GR) or hydroxpyruvate reductase; a liver enzyme. Liver tissue missing this enzyme creates elevated levels of oxalate and cause PH Type II.

Hypercalciuria: High levels of calcium in the urine. A frequent cause of kidney stones.

Hyperoxaluria: High levels of oxalate in the urine

Hypokalemia: Low blood potassium

Inborn: Present from birth, most often hereditary


Kidney failure: A medical condition where the kidneys fail to adequately filter waste products from the blood

Kidney function: A measure of how much blood the kidneys can filter during a given amount of time

Kidney stones: Stones that form in the kidney

Low molecular weight protein: Smaller proteins (< 30,000 Da) that can be filtered by the kidney but are normally completely reabsorbed and therefore not present in urine

Lowe syndrome: A genetic disease manifested by cataracts and cognitive problems that caused by mutations in the OCRL1 gene. Some patients with OCRL1 mutation have kidney findings similar to Dent disease patients (high levels of calcium and low molecular weight proteins).

Microscopy: Examination or viewing of samples (i.e. urine) or objects with a microscope

Mutation: A change in the genetic code (a gene) that in some instances may cause a disease (disease causing mutation)

Nephrocalcinosis: Severe calcification of the kidney

Nephrolithiasis: A stone present in the kidney

ORCL1: Name of the gene that causes some cases of Dent disease. Also causes Lowe syndrome

Osteomalacia: Weak bones

Oxalate: Small molecule that is found in certain plants and is also produced in the liver. Humans cannot degrade oxalate, and it is eliminated by the kidney. It can combine with calcium to make calcium oxalate kidney stones.

Oxalosis: A state where calcium oxalate deposits are found in multiple tissues including blood vessels, bone, eyes and the heart. Oxalosis can occur if the kidney becomes damaged in a patient with PH and oxalate cannot be removed from the body as rapidly as it is produced leading to a buildup of oxalate in the blood.

Parathyroid hormone: Hormone that controls blood calcium by increasing calcium release from bones and production of vitamin D by the kidney

Prevalence: How many have the disease in a given population at a given time


Radiolucent kidney stones: Stones that are not visualized with on a regular x-ray. These stones are, however, seen with other medical imaging techniques such as ultrasound and computerized tomography (CT-scan).

Radiopaque kidney stones: Stones that are visualized with on a regular x-ray

Recessive inheritance: In recessive disorders/diseases, 25% of offsprings/children will have the disease (one copy of the defective gene from each parent), 50% will be asymptomatic carriers (one copy of the gene is defective) and 25% neither carry the defective gene (both copies of the gene are normal) nor have the disease.

Registry: A database used to collect medical records on many patients. Physicians and researchers can learn about a lot about a disease by studying the records of many different patients.



Uloric® (febuxostat): Medication used to treat APRT deficiency

Ultraviolet spectrophotometry: An accurate method used to determine the chemical composition of materials such as kidney stones

Urolithiasis: Stones in the kidney, ureters, or bladder



Xanthine: A substance found in the human body that is closely related to uric acid and 2,8-dihydroxyadenine. All these substances that belong to a group of substances called purines can form kidney stones.

X-linked: A gene that is present on the X-chromosome

X-ray crystallography: An accurate method used to determine the chemical composition of materials such as kidney stones