Autosomal Dominant Pseudohypoaldosteronism Type 1 (AD-PHA1)

Autosomal dominant pseudohypoaldosteronism type 1 is a rare genetic condition. In this condition, the kidneys do not respond properly to the hormone aldosterone. Aldosterone normally helps the kidneys keep salt (sodium) in the body and remove potassium. In AD-PHA1, a change (mutation) in the NR3C2 gene damages the mineralocorticoid receptor, so the kidney “does not listen” to aldosterone. Newborns and infants can lose too much salt in urine and sweat, become dehydrated, have low sodium, high potassium, and acidic blood (metabolic acidosis). This type is usually limited to the kidneys, is autosomal dominant, and often improves with age. Children may need extra sodium early on; many become much better later in childhood. This is different from the autosomal recessive (systemic?) form, which affects many organs. PMC+5MedlinePlus+5MedlinePlus+5

In AD-PHA1, the problem is aldosterone resistance (not a lack of aldosterone). The adrenal glands? produce aldosterone, but kidney cells—especially in the distal nephron? where the epithelial sodium channel (ENaC) and MR work—do not “hear” the signal well. As a result, sodium is lost in urine and potassium builds up in the blood. This is why renin and aldosterone levels are typically elevated, yet fludrocortisone (a mineralocorticoid drug) often does not help. Bioscientifica+1

The genetic cause in the autosomal dominant (renal) form is usually a single disease-causing variant in NR3C2 (haploinsufficiency or dominant-negative effect). The disease tends to be milder than the autosomal recessive (systemic) form and often gets better during childhood; some adults may only show high aldosterone levels with no symptoms. Nature+2BioMed Central+2

Other names

AD-PHA1 is also known as Pseudohypoaldosteronism type 1A (PHA1A), Renal pseudohypoaldosteronism type 1, Mineralocorticoid receptor (MR)–related PHA1, or NR3C2-related PHA1. These names reflect that the problem is in the kidney and is linked to the NR3C2 gene. Orpha+1

Types

1) Renal (autosomal dominant) PHA1 — PHA1A. This is the form described in this article. It is caused by NR3C2 variants and is largely limited to the kidneys. It presents in newborns with salt wasting and hyperkalemia but usually improves with age. Sweat and saliva sodium concentrations are typically normal. Orpha+1

2) Generalized?/systemic (autosomal recessive) PHA1 — PHA1B. This severe? form is caused by variants in the ENaC subunit genes (SCNN1A, SCNN1B, SCNN1G) and affects multiple organs (kidneys, colon?, sweat and salivary glands). It causes very high sodium loss in sweat and stool, frequent chest infections, and persistent symptoms. (Included here only to contrast with AD-PHA1.) Orpha+1

Causes

1) Pathogenic variants in NR3C2 (mineralocorticoid receptor). The core cause of AD-PHA1 is a single harmful change in NR3C2, which reduces the receptor’s function. Orpha

2) Haploinsufficiency. Many cases occur because one working copy of NR3C2 is not enough for normal MR signaling; the reduced dosage? weakens aldosterone effects. Nature

3) Dominant-negative MR variants. Some MR variants can interfere with the normal receptor, worsening resistance and clinical? severity. BioMed Central

4) Missense variants. A single amino-acid change can impair MR’s ability to bind ligand or DNA, reducing sodium reabsorption. OUP Academic

5) Nonsense/frameshift/splice variants. Truncating or splicing defects can abolish MR production or create a nonfunctional protein. Nature

6) Large NR3C2 deletions. Some families lack one or more exons of NR3C2, removing essential receptor regions. Joe Bioscientifica

7) Reduced MR-dependent transcription. Defective MR cannot properly switch on aldosterone-regulated genes that reclaim sodium and secrete potassium. OUP Academic

8) Decreased ENaC activity (secondary). In the renal form, ENaC is present but under-stimulated because MR signaling is weak, so sodium uptake falls. Bioscientifica

9) Intercurrent illness (stressors). Vomiting?, diarrhea?, or fever? can trigger salt-wasting crises in infants with AD-PHA1 because the kidney already struggles to conserve salt. Bioscientifica

10) Low sodium intake. In early life, if dietary sodium is marginal, the impaired MR pathway cannot compensate, precipitating hyponatremia. Bioscientifica

11) Dehydration? or heat exposure. Fluid losses concentrate potassium and magnify salt wasting, revealing the underlying defect. Bioscientifica

12) Medications that raise potassium (ACE inhibitors/ARBs). These drugs reduce aldosterone activity or effect, worsening hyperkalemia in someone already resistant. Merck Manuals

13) Potassium-sparing diuretics (spironolactone, eplerenone, amiloride). These block aldosterone action or ENaC directly and can aggravate hyperkalemia and hyponatremia. Merck Manuals

14) NSAIDs. They can blunt renal prostaglandins and reduce renin/aldosterone dynamics, potentially worsening electrolyte balance in at-risk infants. Merck Manuals

15) Prematurity. Premature kidneys have limited sodium reabsorption capacity; with MR resistance, risks are higher. Bioscientifica

16) Intercurrent urinary tract infections or obstructive uropathy (differential triggers). These conditions can cause secondary aldosterone resistance and must be excluded; in AD-PHA1, underlying MR defect persists. Bioscientifica

17) Metabolic acidosis. Acid-base imbalance from salt loss reduces distal potassium secretion, feeding into hyperkalemia. Merck Manuals

18) Genetic variability within families. Different NR3C2 variants—or the same variant with variable expression—can cause different severities among relatives. PMC

19) Epigenetic or modifier effects. Background genes and developmental factors may modulate clinical severity in AD-PHA1. (Inferred from variable expressivity seen across families.) PubMed

20) Diagnostic delays. Late recognition means longer periods of inadequate salt and fluid replacement, worsening clinical episodes early in life. Bioscientifica

Symptoms and signs

1) Poor feeding and weight gain (failure to thrive?) in early infancy. Babies may feed poorly and gain weight slowly due to chronic? salt loss and dehydration. Genetic & Rare Diseases Info Center

2) Dehydration. Dry mouth, less urine, sunken fontanelle?, and lethargy are common during salt-wasting episodes. Genetic & Rare Diseases Info Center

3) Vomiting. GI upset often accompanies electrolyte imbalance and dehydrates infants further. Bioscientifica

4) Lethargy or irritability. Brain function is sensitive to sodium shifts; babies can be very sleepy or fussy. Bioscientifica

5) Hyponatremia-related symptoms. These include headaches in older children, confusion?, or seizures in severe cases. Merck Manuals

6) Hyperkalemia-related symptoms. Muscle weakness?, flaccidity, or life-threatening heart rhythm changes can occur if potassium is very high. Merck Manuals

7) Metabolic acidosis. Fast breathing or deep respirations may appear as the body tries to balance acid levels. Merck Manuals

8) Low blood pressure or orthostatic dizziness?. Salt loss lowers effective circulating volume. Bioscientifica

9) Normal sweat and saliva sodium. Unlike the systemic form, the renal (AD) form usually does not show high sodium in sweat/saliva. Orpha

10) Episodes often triggered by illness or heat. Stressors can precipitate crises. Bioscientifica

11) Symptoms improve with age. Many children become asymptomatic? by later childhood or adulthood. NCBI

12) Family history?. A parent may have had neonatal? salt-wasting or may be asymptomatic but carry high aldosterone levels. NCBI

13) Normal adrenal cortisol function. Cortisol deficiency is not part of AD-PHA1; the issue is aldosterone resistance. Merck Manuals

14) No chronic lung/sweat gland problems. Recurrent? lung infections and high sweat sodium suggest the recessive systemic form, not AD-PHA1. Orpha

15) Possible neonatal jaundice? or nonspecific malaise around crises. Non-specific stress signs can accompany electrolyte disturbances. Bioscientifica

Diagnostic tests

A) Physical examination

1) Hydration status and vital signs. Check weight, heart rate, blood pressure, mucous membranes, capillary refill; dehydration plus low/normal BP in a sick neonate with salt loss is a red flag. Bioscientifica

2) Growth chart review. Plot weight/length across time; failure to thrive supports chronic salt-wasting. Genetic & Rare Diseases Info Center

3) Signs of hyponatremia. Look for lethargy, irritability, seizures in severe cases. Merck Manuals

4) Signs of hyperkalemia. Muscle weakness or flaccidity may be present; cardiac monitoring is urgent when K⁺ is high. Merck Manuals

5) Differential clues to systemic form. Very salty sweat (salt crystals) or recurrent chest infections point toward recessive systemic PHA1 rather than the renal AD form. Orpha

B) “Manual” bedside tests

6) Orthostatic BP/HR assessment (if age-appropriate). A drop in BP or rise in HR on standing suggests volume depletion from sodium loss. Bioscientifica

7) Capillary refill time. Prolonged refill (>2 seconds) supports dehydration. Bioscientifica

8) Bedside glucose. Hypoglycemia can accompany severe illness in neonates and should be corrected promptly while evaluating electrolytes. Merck Manuals

9) Bedside ECG monitoring. Immediate rhythm monitoring helps detect hyperkalemia-related arrhythmias (peaked T waves, widening QRS). Merck Manuals

10) Urine dipstick and output tracking. Low specific gravity and high output during crises can reflect salt loss; careful input/output measurement guides treatment. Merck Manuals

C) Laboratory and pathological tests

11) Serum electrolytes (Na⁺, K⁺, HCO₃⁻). Hyponatremia, hyperkalemia, and low bicarbonate/metabolic acidosis are typical during episodes. Merck Manuals

12) Blood gas. Confirms metabolic acidosis and helps guide urgent correction. Merck Manuals

13) Plasma renin activity and aldosterone. Both are elevated because the body is trying (unsuccessfully) to retain sodium—this pattern distinguishes PHA1 from hypoaldosteronism. Bioscientifica

14) Serum creatinine/urea. Assesses dehydration impact and kidney function. Merck Manuals

15) Urine sodium and potassium; fractional excretion of sodium (FENa). Inappropriately high urine sodium in the setting of hyponatremia supports renal salt wasting. Bioscientifica

16) Transtubular potassium gradient (TTKG). A low TTKG when potassium is high suggests impaired distal K⁺ secretion consistent with aldosterone resistance. Merck Manuals

17) Sweat chloride/sodium. Usually normal in AD-PHA1; high values point toward systemic recessive PHA1 and other disorders. Orpha+1

18) Genetic testing of NR3C2. Sequencing and deletion/duplication analysis confirm the autosomal dominant, renal form; testing parents clarifies inheritance and recurrence risk. Joe Bioscientifica+1

19) Targeted ENaC gene testing (SCNN1A/B/G) when systemic form suspected. Consider if sweat sodium is high or symptoms are severe/persistent beyond the kidney. Orpha

D) Electrodiagnostic tests

20) Twelve-lead ECG. Detects hyperkalemia changes (peaked T waves, PR prolongation, QRS widening) and guides urgent therapy; repeat as potassium normalizes. Merck Manuals

21) Continuous cardiac monitoring (telemetry). Used during acute correction of hyperkalemia to detect arrhythmias early. Merck Manuals

E) Imaging tests

22) Renal and bladder ultrasound. Looks for structural uropathy or infection-related changes that can mimic or worsen salt-wasting and should be ruled out. Bioscientifica

23) Chest radiograph (if clinically indicated). Consider during severe illness or if systemic form suspected with recurrent infections; not routinely needed for AD-PHA1. Orpha

24) Echocardiography (selected cases). Rarely used; may be considered if severe hyperkalemia produces concerning rhythms or if dehydration is profound; primarily to exclude other pathology. Merck Manuals

Non-pharmacological treatments (therapies & others)

There is no evidence for gene or stem-cell therapy in AD-PHA1 today. These practical measures do help and are used in clinics.

1. Personalized sodium plan
   A pediatrician/nephrologist sets an oral sodium chloride (NaCl) plan for daily use, adjusted to growth, labs, and symptoms. The goal is to prevent dehydration and keep sodium in the normal range. Doses often decrease with age as kidneys cope better. Parents are taught how to mix sodium solutions safely and to never improvise without medical advice. Regular labs check sodium, potassium, and acid–base status to guide dosing. PMC

2. Sick-day and heat plans
   Illness, fever, vomiting, diarrhea, or hot weather can trigger salt loss. Families get written sick-day rules: increase fluids, use the clinician-approved sodium plan, watch for signs of dehydration (dry mouth, no tears, less urine), and seek care early. In hot climates, proactive hydration and shaded, cool environments are essential. PMC

3. Low-potassium diet during flares
   Daily diets can be normal for many children, but during hyperkalemia risk or illness, clinicians may recommend temporarily limiting high-potassium foods (some juices, bananas, potatoes) while ensuring adequate calories and nutrients. Diet changes are guided by a clinician/dietitian to avoid malnutrition. PMC

4. Oral rehydration solutions (ORS) for intercurrent illness
   Clinician-approved ORS helps replace both water and electrolytes during gastroenteritis. Parents learn which products to use and how much to give based on weight and age, and when to escalate to medical care. PMC

5. Home monitoring & early warning
   Daily weights (for infants), urine output tracking, and symptom logs help catch salt-wasting early. Families also keep a written emergency plan (what to do, where to go, whom to call). PMC

6. Medication review to avoid potassium-raising drugs
   Clinicians screen for medicines that can raise potassium or worsen kidney handling (e.g., ACE inhibitors, ARBs, potassium-sparing diuretics, high-dose NSAIDs) and either avoid them or monitor very closely. NCBI

7. Care coordination (pediatrics, nephrology, endocrinology, dietetics)
   Because needs change as children grow, a team coordinates sodium dosing, lab frequency, nutrition, vaccination/illness guidance, and school/day-care planning. PMC

8. Family education & genetic counseling
   Because this condition is autosomal dominant, a parent may carry the variant. Genetic counseling explains recurrence risk and options for family testing. Education helps caregivers understand sick-day rules and prevents dangerous delays in care. MedlinePlus

9. Temperature and sweat management
   Heat increases sweat sodium loss. Practical steps include light clothing, cool environments, and planned, frequent fluids during hot seasons or exertion. PMC

10. Vaccination and infection control
    Infections can dehydrate children quickly. Up-to-date vaccines, early fever management, and prompt care for vomiting/diarrhea reduce emergency events. PMC

11. School/day-care action plans
    Written instructions for trusted adults (symptoms to watch, when to call parents or emergency services, permitted drinks/ORS). PMC

12. Transition planning to adult care
    As symptoms often improve, adolescents still benefit from education on recognizing dehydration, keeping regular checkups, and sharing their condition and medication list with new providers. NCBI

Drug treatments

There are no FDA-approved drugs specifically for AD-PHA1. Medicines are used to treat complications, mainly hyperkalemia or acidosis, or to replace sodium. Below are the core options with FDA-label citations.

A. Oral sodium chloride
Purpose: replace sodium losses and prevent dehydration. Given as clinician-prescribed NaCl solution or mixed capsules/solutions. Dose is individualized, often higher in infancy and reduced over time. Mechanism: provides sodium that kidneys fail to retain due to aldosterone resistance. (General management principle for renal PHA1; not an FDA-labeled product for this indication.) PMC

B. Potassium binders (for hyperkalemia)

1. Sodium polystyrene sulfonate (Kayexalate) – exchanges sodium for potassium in the gut to lower serum potassium. Label notes variable efficacy and GI risks (including rare colonic necrosis); avoid in neonates with reduced gut motility; careful administration is required. Dosing is weight- and situation-specific; clinicians monitor electrolytes closely. FDA Access Data+2FDA Access Data+2

2. Patiromer (Veltassa) – a non-absorbed polymer that binds potassium in the colon. Indicated for hyperkalemia; not for emergency/life-threatening hyperkalemia. Adult starting dose often 8.4 g once daily, titrated to effect; pediatric dosing exists for ≥12 years in label updates. Separate from other oral drugs (binding interactions). FDA Access Data+2FDA Access Data+2

3. Sodium zirconium cyclosilicate (Lokelma) – inorganic cation exchanger that captures potassium; 10 g three times daily for up to 48 hours for initial correction in adults, then maintenance (e.g., 10 g daily, adjusted). Not for emergency/life-threatening hyperkalemia due to delayed onset. Monitor for edema due to sodium load. FDA Access Data+2FDA Access Data+2

C. Emergency hyperkalemia protocols (hospital use)
Depending on severity and ECG changes, clinicians may use:

• IV calcium gluconate (stabilizes cardiac membrane; does not lower potassium),

• Insulin plus dextrose (drives potassium into cells),

• Nebulized albuterol (β2-agonist shifts potassium intracellularly),

• Sodium bicarbonate (in acidosis), and IV fluids. These are standard emergency measures used per pediatric protocols; dosing and monitoring occur in the hospital. (Use is guided by clinical practice and drug labels for each product.) NCBI

D. Fludrocortisone
In renal (autosomal dominant) PHA1, mineralocorticoids typically do not correct salt wasting because the mineralocorticoid receptor is impaired. Therefore, they are usually ineffective and not a long-term solution for AD-PHA1. PMC

If you want, I can build a full drug compendium (up to 20 items) with FDA-label snippets and dosing ranges for different ages/settings; I kept this section realistic to what’s actually used in AD-PHA1.

Dietary “molecular supplements

There are no special “molecular supplements” proven to treat AD-PHA1. Helpful nutrition focuses on safe sodium replacement and potassium awareness under clinical guidance:

• Clinician-approved sodium solutions (NaCl) mixed to a prescribed concentration to meet daily sodium needs; not over-the-counter sports drinks. PMC

• Oral rehydration solution (ORS) during illnesses to replace water and electrolytes, under a pediatric plan. PMC

• Temporary low-potassium food choices during periods of hyperkalemia risk, guided by a dietitian so growth and nutrition remain normal. PMC

Immunity booster / regenerative / stem-cell drugs

There are no FDA-approved immune boosters, regenerative medicines, or stem-cell treatments for AD-PHA1. Management is supportive and focused on salt balance and potassium control. Any claim to the contrary is not evidence-based. PMC

Surgeries

There are no surgeries that treat or cure AD-PHA1. Surgery is not part of standard care for this kidney-limited hormone resistance. PMC

Preventions

1. Follow the personalized sodium plan and lab schedule. PMC

2. Written sick-day rules for fever, vomiting, or diarrhea. PMC

3. Heat management: fluids, shade, breaks. PMC

4. Avoid potassium-raising drugs (unless necessary with monitoring). NCBI

5. Early care for GI illnesses to prevent dehydration. PMC

6. Dietitian-guided potassium awareness during risk periods. PMC

7. Care coordination with specialists. PMC

8. Family education and emergency plan. PMC

9. Genetic counseling for family planning/testing. MedlinePlus

10. Regular follow-up because needs often change with age. NCBI

When to see a doctor

• Immediately for poor feeding, repeated vomiting, lethargy, fainting, very little urine, or high fever—these can mean dehydration or dangerous electrolyte changes.

• Urgently for signs of high potassium, such as weakness, palpitations, or unusual heart symptoms.

• Routinely for lab checks, dose adjustments, growth monitoring, and diet review, especially after illnesses or during hot seasons. PMC

What to eat / what to avoid

Eat: balanced meals for age with enough calories and protein; clinician-approved sodium solutions in the doses prescribed; normal foods most of the time if potassium is normal; ORS during gastroenteritis per pediatric plan. PMC

Avoid (or limit during risk periods): very high-potassium foods (certain fruit juices, bananas, potatoes) when potassium is high; over-the-counter salt substitutes (many contain potassium); and sports/energy drinks that do not match the sodium plan. Never change sodium or fluid plans without your clinician’s advice. PMC

Frequently Asked Questions

1. Is AD-PHA1 the same as the severe systemic type?
   No. AD-PHA1 is kidney-limited and often improves with age; the systemic (autosomal recessive) type involves many tissues and is more severe. Orpha

2. What gene is involved?
   NR3C2, which makes the mineralocorticoid receptor. MedlinePlus

3. Why is sodium so important here?
   Sodium is lost in urine and sweat because the kidney does not respond to aldosterone. Replacing it prevents dehydration. PMC

4. Will my child outgrow it?
   Many children with AD-PHA1 need less sodium over time and may be well later in childhood, but they still need follow-up. PMC

5. Do aldosterone-like drugs fix it?
   Usually not in AD-PHA1; the receptor itself is the problem. PMC

6. Is there a special vitamin or supplement that cures it?
   No. There is no supplement proven to fix AD-PHA1. PMC

7. How is high potassium treated?
   Diet steps, potassium binders (Kayexalate, patiromer, SZC), and emergency hospital measures if severe. FDA Access Data+2FDA Access Data+2

8. Are potassium binders safe for infants?
   Use is clinician-directed. SPS has important GI warnings; newer binders have age limits and specific dosing. Always follow pediatric specialist guidance. FDA Access Data

9. Can we use sports drinks for salt?
   No—use the prescribed sodium plan; sports drinks usually do not contain the right amount of sodium and may add unwanted potassium. PMC

10. Do we need a genetic counselor?
    Yes. AD inheritance affects family planning and testing. MedlinePlus

11. What triggers crises?
    Illness with vomiting/diarrhea, fever, heat, poor intake, or drugs that raise potassium. PMC+1

12. Is surgery ever needed?
    No. There is no surgery for AD-PHA1. PMC

13. What specialists should we see?
    Pediatrics plus nephrology/endocrinology; a dietitian helps with growth and potassium plans. PMC

14. What labs are checked?
    Sodium, potassium, bicarbonate/CO₂ (acid–base), and sometimes renin/aldosterone, guided by the clinician. PMC

15. Where can I read more in plain language?
    MedlinePlus Genetics and Orphanet provide accessible summaries. MedlinePlus+1

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Last Updated: October 04, 2025.