Rare Medical News

Spotlight On

Cystinuria

Cystinuria is an inherited condition characterized by a buildup of the amino acid, cystine, in the kidneys and bladder

Prevalence

1-5 / 10 000

33,100 - 165,500

US Estimated

51,350 - 256,750

Europe Estimated

Age of Onset

ageofonset-all.svg

ICD-10

E72.0

Inheritance

Autosomal dominant

no.svg

Autosomal recessive

rnn-autosomalrecessive.svg

Mitochondrial/Multigenic

no.svg

X-linked dominant

no.svg

X-linked recessive

no.svg

Rare View

Cystinuria is a rare condition in which stones made from an amino acid called cysteine form in the kidney, ureter, and bladder. Cystinuria is caused by mutations in the SLC3A1 and SLC7A9 genes. Mutations in either of these genes disrupt the ability of this transporter protein to reabsorb these amino acids, allowing them to become concentrated in the urine. As the levels of cystine in the urine increase, it forms cystine crystals, resulting in kidney stones. Cystine crystals form hexagonal-shaped crystals that can be viewed upon microscopic analysis of the urine. People with cystinuria pass stones monthly, weekly, or daily, and need ongoing care.

rv-cystinuria.svg

5 Facts you should know

FACT

1

Cystinuria is characterized by the inadequate reabsorption of cystine in the proximal convoluted tubules

FACT

2

This leads to the formation of cystine crystals and/or stones which may block the urinary tract

FACT

3

Signs and symptoms of the condition are related to the presence of stones and may include nausea, hematuria, flank pain, and/or frequent urinary tract infections

FACT

4

It is usually an inherited condition characterized by a buildup of cystine in the kidneys and bladder

FACT

5

Cystinuria is caused by changes (mutations) in the SLC3A1 and SLC7A9 genes and is inherited in an autosomal recessive manner

Cystinuria is also known as...

Cystinuria

CSNU; Cystinuria-lysinuria

What’s your Rare IQ?

Typically, what color are cystine stones when removed?

Common signs & symptoms

Abnormality of amino acid metabolism

Hematuria

Blood in urine

Nephrolithiasis

Kidney stones

Hyperuricemia

High blood uric acid level

Renal insufficiency

Renal failure

Abnormality of the nervous system

Neurologic abnormalities

Argininuria

 High urine arginine levels

High urine arginine levels

High urine lysine levels

Current treatments

Treatment of cystinuria is focused on relieving symptoms and preventing the formation of additional stones. A more conservative approach is typically tried first. This may include increasing fluid intake, regular monitoring of urinary pH, dietary restrictions (i.e. eating less salt) and increasing the pH of urine with potassium citrate supplements. If these strategies do not prevent the formation of stones, medications may be added to help dissolve the cystine crystals.[1][2][3]

Treatment for cystinuria-related stones varies depending on the size and location of the stone, but may include:[1][2][3]

Medscape Reference's Web site offers more specific information regarding the treatment and management of cystinuria. Please click on the link to access this resource.

FDA-Approved Treatments

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition. Learn more orphan products.

Tiopronin

(Brand name: Thiola®) Manufactured by Retrophin, Inc.
FDA-approved indication: Prevention of cystine nephrolithiasis in patients with homozygous cystinuria.

Top Clinical Trials

TitleDescriptionPhasesStatusInterventionsMore Information
Lipoic Acid Supplement for Cystine StoneThis study evaluates how daily alpha lipoic acid supplementation affects cystine kidney stone recurrence. Half of the subjects will receive 1200 mg alpha lipoic acid orally daily for three years, while the other half will receive a placebo.Phase 2Active, not recruitingDietary Supplement: Alpha lipoic acid|Drug: PlaceboClick here for more information
The Effect of Sodium-glucose Cotransporter (SGLT) 2 Inhibitors on Cystine Stone Formation: A Preliminary StudyThis is a single center, proof of concept prospective cohort trial designed to assess the effect of daily oral administration of dapagliflozin on cystine formation in freshly voided urine. Phase 2RecruitingDrug: DapagliflozinClick here for more information

Top Treatments in Research

AgentClass/Mechanism of ActionDevelopment StatusCompanyClinical StudiesMore Information
Lipoic AcidLipoic acid (LA), also known as α-lipoic acid, alpha-lipoic acid (ALA) and thioctic acid, is an organosulfur compound derived from caprylic acid (octanoic acid)Phase 2Thomas Chi, MD, University of California, San FranciscoClick here for more informationClick here for more information
SGLT 2 InhibitorsSGLT-2 inhibitor is an abbreviation for sodium-glucose cotransporter-2 inhibitors. SGLT-2 inhibitors are a class of medicine used to lower high blood glucose levels in people with type 2 diabetesPhase 2University of California, San FranciscoClick here for more informationClick here for more information

Medline Plus, National Library of Medicine