ConditionKidneys & urinary tract
Bartter Syndrome
Bartter syndrome is a group of rare inherited kidney disorders in which part of the kidney tubule cannot reabsorb salt properly. The body loses large amounts of salt, water and potassium in the urine, causing low potassium, a blood alkalosis (too little acid) and dehydration with normal or low blood pressure. Severe forms start before birth or in infancy, with excess amniotic fluid, premature birth, heavy urination and poor growth. Lifelong supplements and medicines control it.
Also called: Bartter's syndrome, salt-losing tubulopathy, hypokalemic salt-losing tubulopathy
At a glance
- What it is
- Inherited kidney tubule defects causing salt, water and potassium loss.
- Key lab findings
- Low potassium, metabolic alkalosis, high renin and aldosterone, normal or low blood pressure.
- Who gets it
- Present from birth. Antenatal forms appear before birth; classic forms in early childhood.
- Symptoms
- Heavy urination, thirst, dehydration, poor growth, weakness, cramps, kidney calcium deposits.
- Treatment
- Salt and potassium supplements, NSAIDs such as indomethacin, and potassium-sparing diuretics.
When to get help
Call 911 or go to the ER
- A baby or child with vomiting or diarrhea who becomes floppy, very drowsy, or stops passing urine
- Severe muscle weakness, inability to stand, or palpitations and fainting (possible dangerously low potassium)
See a doctor within a day or two
- A child with Bartter syndrome who cannot keep supplements or fluids down
- Fever with vomiting or diarrhea in a known patient, as dehydration develops fast
Book a routine appointment
- Poor weight gain, frequent urination at night or excessive thirst in a child
- Muscle cramps, weakness or fatigue with known low potassium
How Bartter syndrome works
The kidney filters large amounts of salt each day and reabsorbs most of it. In Bartter syndrome, gene variants disable the transport proteins in a section of the tubule called the thick ascending limb of the loop of Henle. This is the same site where loop diuretics such as furosemide act, so Bartter syndrome behaves like lifelong, uncontrolled diuretic use.
Salt loss leads to:
- loss of water and low blood volume, triggering high renin and aldosterone
- increased potassium and acid loss in the urine, producing hypokalemia and metabolic alkalosis
- high calcium in the urine (in most types), causing calcium deposits in the kidneys (nephrocalcinosis)
- high prostaglandin E2 production, which worsens salt loss and causes fever, vomiting and diarrhea in infants
Types
| Type | Gene | Features |
|---|---|---|
| Type 1 and 2 (antenatal) | SLC12A1, KCNJ1 | Excess amniotic fluid, premature birth, severe salt loss, nephrocalcinosis. Type 2 can have temporary high potassium at birth |
| Type 3 (classic) | CLCNKB | Onset in infancy or childhood, variable severity, may resemble Gitelman syndrome |
| Type 4a and 4b | BSND, or CLCNKA plus CLCNKB | Antenatal onset with sensorineural deafness |
| Type 5 (transient antenatal) | MAGED2 | X-linked, severe before birth but resolves within weeks to months |
Most types are autosomal recessive: both parents carry one copy of the gene variant.
Symptoms
Before and around birth (antenatal Bartter)
- polyhydramnios (excess amniotic fluid) from heavy fetal urination, often from mid-pregnancy
- premature birth
- heavy urination, dehydration and weight loss after birth
- fever, vomiting and poor feeding
In childhood (classic Bartter)
- excessive thirst and urination, including bedwetting
- salt craving
- poor growth and failure to thrive
- muscle weakness, cramps and tiredness from low potassium
- constipation
- a triangular face and prominent forehead in some children
- kidney stones and nephrocalcinosis
Blood pressure is normal or low, which separates Bartter syndrome from other causes of low potassium with alkalosis such as aldosterone-producing tumors.
Bartter vs Gitelman syndrome
| Bartter syndrome | Gitelman syndrome | |
|---|---|---|
| Kidney site | Loop of Henle | Distal tubule |
| Age at onset | Before birth or childhood | Usually adolescence or adulthood |
| Severity | Often severe | Usually milder |
| Urine calcium | High | Low |
| Blood magnesium | Usually normal | Low |
| Growth problems | Common | Uncommon |
Diagnosis
- Blood tests: low potassium, high bicarbonate (alkalosis), high renin and aldosterone, normal or low magnesium.
- Urine tests: high sodium, chloride, potassium and usually calcium despite low blood levels.
- Kidney ultrasound: nephrocalcinosis.
- Genetic testing: confirms the type and helps family planning.
- Hearing tests for type 4.
Doctors rule out hidden diuretic or laxative use and chronic vomiting, which can cause similar blood results.
Treatment
Treatment is lifelong and aims to correct salt and potassium losses and support growth.
- Salt (sodium chloride) and potassium chloride supplements, often several times a day. Potassium is hard to normalize completely, so the goal is a safe level and good symptoms.
- NSAIDs, especially indomethacin, reduce prostaglandin-driven salt loss and are very effective in antenatal forms. Side effects on the stomach and kidneys are monitored.
- Potassium-sparing diuretics such as spironolactone or amiloride help some patients.
- Good hydration and free access to water and salt.
- Nutrition and growth support, sometimes growth hormone for persistent short stature.
- Sick-day plans: extra fluids and early medical care during vomiting, diarrhea or fever, as dehydration develops quickly.
- Monitoring: regular blood tests, growth checks and kidney ultrasound.
Complications and outlook
Complications include dehydration crises, heart rhythm problems from low potassium, nephrocalcinosis, kidney stones, and in some people chronic kidney disease over time. Hearing loss is permanent in type 4. With consistent treatment, most children grow and develop well and reach adulthood. Pregnancy in women with Bartter syndrome needs specialist care.
Frequently asked questions
What is Bartter syndrome?
It is a rare inherited kidney disorder in which the kidneys cannot reabsorb salt normally. This causes loss of salt, water and potassium in the urine, leading to low potassium, dehydration and alkalosis. It usually appears before birth or in childhood.
What are the symptoms of Bartter syndrome in babies?
Babies often have a history of excess amniotic fluid and premature birth, then pass large amounts of urine, become dehydrated, feed poorly, vomit and fail to gain weight. Some have fever without infection. Blood tests show low potassium and alkalosis.
How is Bartter syndrome different from Gitelman syndrome?
Both are inherited salt-wasting disorders with low potassium. Bartter syndrome affects the loop of Henle, starts earlier, is usually more severe, and causes high urine calcium. Gitelman syndrome starts later, is milder, and causes low urine calcium and low magnesium.
Is Bartter syndrome curable?
There is no cure, as it is genetic. Lifelong treatment with salt and potassium supplements, NSAIDs and sometimes potassium-sparing diuretics controls symptoms and supports normal growth. The transient type 5 resolves on its own after birth.
Is Bartter syndrome inherited?
Yes. Most types are autosomal recessive, so both parents carry one altered gene and each pregnancy has a 1 in 4 chance of an affected child. Type 5 is X-linked. Genetic counseling is recommended for families.
Sources
This guide was written from current patient and clinical guidance, including:
- NIH Genetic and Rare Diseases Information Center: Bartter syndrome
- MedlinePlus Genetics: Bartter syndrome
- National Organization for Rare Disorders: Bartter syndrome
- Konrad M, et al. Diagnosis and management of Bartter syndrome: consensus of the ERKNet working group (Nature Reviews Nephrology)
- National Kidney Foundation: Hypokalemia