Condition Deep-Dives 11 min read·Updated 22 July 2026 Clinician-reviewed

Nephronophthisis (NPHP)

A UK Consultant Nephrologist on nephronophthisis — the commonest genetic cause of childhood-onset ESKD, often missed because the kidneys look small and the urine looks normal.

  • Clinically Reviewed
  • NHS & NICE Aligned
  • UK Evidence-Based
  • Last Reviewed 22 July 2026

Professor Mohammed Mahdi Althaf

Consultant Nephrologist & Acute Physician

View Credentials

Professor Mohammed Mahdi Althaf

MD, MSc, PgDip (Clin Ed), FRCP, FHEA, FASN

Consultant Nephrologist & Acute Physician · GMC 7216325

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Direct answer

Autosomal recessive ciliopathy. Polyuria, polydipsia, anaemia, growth failure, small-to-normal echogenic kidneys ± corticomedullary cysts. Confirm with NPHP gene panel (NHS R193/R194). No specific treatment — support and plan for transplant; disease does NOT recur.

Key recommendation: Commonest genetic cause of paediatric ESKD.

Quick answer

✓ Best choices

  • Vegetables, lower-potassium fruit and whole grains
  • Sensible portions of fish, eggs, chicken or tofu
  • Olive oil and unsalted nuts in small amounts

✓ Foods to limit

  • Added salt and ultra-processed foods
  • Phosphate additives in processed meats and ready meals
  • Sugary and energy drinks

Key takeaway

Autosomal recessive ciliopathy. Polyuria, polydipsia, anaemia, growth failure, small-to-normal echogenic kidneys ± corticomedullary cysts. Confirm with NPHP gene panel (NHS R193/R194). No specific treatment — support and plan for transplant; disease does NOT recur.

Who should be cautious

People on dialysis, post-transplant, pregnant or breastfeeding, or taking prescription medication — confirm with your renal team before changes.

Nephronophthisis (NPHP)

Genetics & forms

GENES (> 25 identified):

  • NPHP1 (commonest — ~ 20%; 290 kb homozygous deletion screen first)
  • NPHP2 (INVS) — infantile form
  • NPHP3 — adolescent form, hepatic fibrosis
  • NPHP4, NPHP5 (IQCB1) — Senior-Løken
  • NPHP6 (CEP290) — Joubert / Meckel
  • NPHP10 (SDCCAG8) — Bardet-Biedl overlap
  • All encode 'nephrocystins' localising to the primary cilium
  • Autosomal recessive; 25% sibling recurrence

Clinical Forms

  • INFANTILE (NPHP2): ESKD < 4 years; often enlarged cystic kidneys + situs inversus
  • JUVENILE (NPHP1): median ESKD age 13; commonest
  • ADOLESCENT/ADULT (NPHP3): ESKD 15–30 years

Syndromic Associations

  • Senior-Løken — retinitis pigmentosa + NPHP
  • Joubert — cerebellar vermis hypoplasia (molar tooth sign), apnoea, ataxia
  • Meckel-Gruber — occipital encephalocele, polydactyly, lethal
  • Bardet-Biedl — obesity, polydactyly, retinopathy, hypogonadism
  • Cogan oculomotor apraxia, Caroli disease overlap

Clinical features & diagnosis

Presentation

  • Polyuria, polydipsia (concentrating defect early)
  • Secondary nocturnal enuresis in older children
  • Growth failure, fatigue
  • Anaemia disproportionate to eGFR
  • No / minimal proteinuria
  • Blood pressure often NORMAL or low (salt wasting) until ESKD
  • Extrarenal symptoms (visual loss, ataxia) in syndromic forms

Bloods

  • Rising creatinine over months/years
  • Anaemia
  • Normal or low Na, low K, low Mg (salt-wasting)

Urine

  • Low specific gravity, low osmolality despite fluid restriction
  • Minimal proteinuria, no haematuria

Imaging

  • Ultrasound: small-to-normal echogenic kidneys; LOSS of corticomedullary differentiation; corticomedullary cysts (often LATE finding; absent in 30%)
  • MRI/CT can show cysts not seen on US

BIOPSY (if genetics negative or unclear):

  • Diffuse tubular atrophy and interstitial fibrosis
  • Tubular basement membrane disruption/thickening (pathognomonic)
  • Cysts at corticomedullary junction
  • Relatively preserved glomeruli early

Genetics

  • NHS R193 (cystic kidney) and R194 (ciliopathy) panels
  • Step 1: NPHP1 deletion (MLPA)
  • Step 2: NGS panel of NPHP genes
  • Definitive diagnosis — avoids biopsy

Management & transplant

General

  • Free access to water and salt (do NOT restrict)
  • Salt supplementation often needed
  • Monitor and replace Mg, K
  • Treat anaemia (iron + ESA)
  • Renal bone disease — vitamin D, phosphate as per stage
  • ACE-i / ARB if hypertension or proteinuria
  • No specific drug therapy (no role for tolvaptan)

Dialysis

  • Most need RRT in childhood / adolescence
  • Pre-emptive transplant preferred
  • PD or HD as standard pathway

Transplant

  • Disease does NOT recur in graft — excellent long-term outcomes
  • Living donors (heterozygous parents are unaffected)
  • Standard immunosuppression
  • Screen donors for NPHP1 deletion if related

Extrarenal Surveillance

  • Annual ophthalmology — ERG/OCT (Senior-Løken)
  • MRI brain if neurological features (Joubert)
  • Liver imaging / LFTs (NPHP3 hepatic fibrosis)
  • Echo + situs if NPHP2
  • Multidisciplinary clinic

Family

  • Genetic counselling — 25% sibling recurrence
  • Cascade testing
  • Prenatal diagnosis / PGD available

UK Pathway

  • Paediatric nephrology + clinical genetics from diagnosis
  • Transition to adult renal genetics clinic in late teens
  • National Renal Genetics Service input
ARPKD — Autosomal Recessive Polycystic Kidney Disease
Related reading: ARPKD — Autosomal Recessive Polycystic Kidney Disease.

Key practical tips

Designed for quick scanning — what to order, what to avoid, sensible portions, common mistakes.

  • Cook from scratch when you can
  • Read sodium labels (≤ 0.3 g per 100 g is low)
  • Take any concerns to your GP or renal team early

Clinical guidance

TL;DR summary

Autosomal recessive ciliopathy. Polyuria, polydipsia, anaemia, growth failure, small-to-normal echogenic kidneys ± corticomedullary cysts. Confirm with NPHP gene panel (NHS R193/R194). No specific treatment — support and plan for transplant; disease does NOT recur.

Key takeaways
  • Commonest genetic cause of paediatric ESKD.
  • Polyuria / polydipsia / nocturnal enuresis are early clues.
  • Kidneys are SMALL or normal (not enlarged like ADPKD).
  • Extrarenal features in up to 15% (eye, brain, liver).
  • Does not recur after kidney transplant.
Kidney Diet & Nutrition Considerations

Diet is one of the most powerful tools you have to look after your kidneys. UK renal guidance points to a Mediterranean-style, reduced-salt pattern: plenty of vegetables, lower-potassium fruit, whole grains, sensible protein, beans and pulses in moderation, oily fish and olive oil. Personal targets — for potassium, phosphate, protein and fluid — should be set by your renal team based on your bloods.

Foods to prioritise

  • Vegetables, lower-potassium fruit and whole grains
  • Sensible portions of fish, eggs, chicken or tofu
  • Olive oil and unsalted nuts in small amounts

Foods to limit

  • Added salt and ultra-processed foods
  • Phosphate additives in processed meats and ready meals
  • Sugary and energy drinks

Potassium, phosphate and protein needs vary between individuals — please confirm personal targets with your renal team or dietitian. Browse the Kidney Diet Hub for more guides in this cluster.

Frequently asked questions

What is nephronophthisis?

Nephronophthisis (NPHP) is an autosomal recessive ciliopathy and the COMMONEST genetic cause of end-stage kidney disease in children and adolescents. It is characterised by reduced urinary concentrating ability (polyuria/polydipsia), tubular atrophy, interstitial fibrosis and small to normal-sized kidneys with corticomedullary cysts on imaging. Over 25 NPHP genes are recognised; NPHP1 deletion is the commonest (~ 20% of cases).

How does it present?

Three forms by age: INFANTILE (NPHP2 — INVS) — ESKD before age 4, often with extrarenal features. JUVENILE (commonest, NPHP1) — polyuria, polydipsia, enuresis, anaemia, growth failure → ESKD at median age 13. ADOLESCENT/ADULT (NPHP3) — ESKD between 15–30 years. Up to 15% have extrarenal features: retinitis pigmentosa (Senior-Løken), cerebellar ataxia (Joubert), liver fibrosis, situs inversus or skeletal dysplasia.

How is it diagnosed?

Suspect in any child or young adult with unexplained CKD, polyuria, anaemia and small-to-normal echogenic kidneys with corticomedullary cysts on ultrasound (cysts may be absent early). Biopsy shows tubular basement membrane thickening/disruption, tubular atrophy, interstitial fibrosis, with relative sparing of glomeruli. CONFIRM with NHS National Genomic Test Directory R193/R194 (cystic kidney/ciliopathy gene panel) — NPHP1 deletion screening first, then full panel.

What is the treatment?

No disease-modifying treatment exists. Management is supportive: maintain salt and water intake (avoid dehydration — patients are obligate salt-losers), nutritional support, treat anaemia and renal bone disease, ACE-i/ARB for proteinuria/hypertension. Plan for renal replacement therapy and transplantation early. Disease does NOT recur in the graft. Screen for and manage extrarenal features (annual ophthalmology, neurology, liver imaging as guided by genotype).

What foods are good for kidney health?

A Mediterranean-style, mostly plant-based, reduced-salt diet is the most consistent evidence-based pattern for kidney health. Build meals around vegetables, lower-potassium fruit, whole grains, fish, eggs or tofu, beans and pulses in moderation, and olive oil.

Nutritional challenges in kidney disease

Many people living with kidney disease have to limit foods because of potassium, phosphate, diabetes, dialysis, appetite changes or simply the time it takes to cook from scratch every day. That can make it harder to keep daily nutrition balanced — particularly for vitamins and minerals that food alone may not fully cover.

Kidney Vitality is a UK-formulated daily nutritional support product designed by Consultant Nephrologist Professor Mohammed Mahdi Althaf with renal nutrition in mind from the start. It keeps doses moderate, leaves out added potassium, phosphate and magnesium, and avoids megadose vitamin A — sitting alongside a kidney-friendly diet, not replacing it.

Why Kidney Vitality fits this need

Built around UK guidance

Aligned with British Association for Paediatric Nephrology, NHS National Genomic Test Directory R193/R194, UK Genetic Renal Service guidance and KDIGO 2024 CKD evaluation.

Designed by a UK Consultant Nephrologist

Formulated and reviewed by Professor Mohammed Mahdi Althaf (GMC 7216325).

Genotype-led & transplant-focused

Practical guidance on the NPHP gene panel, syndromic features and excellent post-transplant outcomes.

Designed by a UK Consultant Nephrologist

Ready to support your kidney health?

If you have been researching kidney health, supplements, CKD nutrition or kidney-friendly living, Kidney Vitality was developed specifically around those principles by Professor Mohammed Mahdi Althaf (GMC 7216325). Nephrologist Developed Daily Multivitamin.

  • No Added Potassium
  • No Added Magnesium
  • No Added Phosphorus
  • No Added Iron
  • One capsule daily
  • UK GMP — BRCGS, NSF GMP, Halal
Subscribe & Save — £20.39/monthCheck your current multivitamin

✓ Free UK tracked delivery  ·  ✓ Delivered every 30 days  ·  ✓ Pause or cancel anytime  ·  ✓ Never run out

ComparisonKidney VitalityTypical high-street multivitamin
Added potassiumNoneOften included
Added phosphateNoneOften included (E338–E452)
Vitamin A (retinol)No megadoseOften high-dose retinol
Kidney-focused formulationYesNo — general population
Consultant Nephrologist involvementYes (GMC 7216325)No
UK GMP manufacturedYes (BRCGS, NSF GMP)Varies

Food supplement. Not a medicine and not a treatment for kidney disease. Speak with your GP, pharmacist or renal team before starting any new supplement, especially in advanced CKD, on dialysis, post-transplant, pregnant or breastfeeding.

Clinical reviewer

Professor Mohammed Mahdi Althaf

Consultant Nephrologist

Acute Physician

GMC 7216325

View Full Biography

Professor Mohammed Mahdi Althaf is a UK Consultant Nephrologist and Acute Physician with a special interest in chronic kidney disease, AKI prevention and renal nutrition. He combines hospital practice with patient education and clinical guidance review.

View professional profile →
View Credentials
  • MD
  • MSc
  • PgDip (Clin Ed)
  • FRCP
  • FHEA
  • FASN

About this article

Written for UK patients and based on:

  • NICE guidance
  • NHS resources
  • British Dietetic Association guidance
  • Kidney Care UK resources
View methodology

Each article is researched against current UK clinical guidance (NICE NG203, NG118, NG136), NHS patient resources, KDIGO and KDOQI international guidelines, and the British Dietetic Association Renal Nutrition Group. Drafts are written by the Kidney Vitality editorial team and reviewed by a UK Consultant Nephrologist before publication. Content is reviewed on a rolling basis and updated when guidance changes.

Editorial standards

  • Clinically reviewed
  • NHS-aligned
  • NICE-aligned
  • Evidence-based
  • Reviewed before publication
View full editorial process

Every article is researched and written by the Kidney Vitality editorial team using current UK clinical guidance (NICE NG203, NG118, NG136), NHS patient resources, KDIGO/KDOQI international guidelines, and British Dietetic Association renal nutrition guidance. Drafts are reviewed for clinical accuracy by Professor Mohammed Mahdi Althaf, MD, MSc, PgDip (Clin Ed), FRCP, FHEA, FASN (Consultant Nephrologist & Acute Physician, GMC 7216325) before publication. Content is updated when UK guidance changes.

References (4)View Sources
  1. NICE NG203: Chronic kidney disease — assessment and management
  2. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD
  3. KDOQI Clinical Practice Guideline for Nutrition in CKD: 2020 Update
  4. British Dietetic Association — Renal Nutrition Group

Medical disclaimer

This content is educational only and does not replace personalised medical advice.

Read full disclaimer

This page is general information, not personal medical advice. If you have chronic kidney disease, are on dialysis, have had a kidney transplant, are pregnant or breastfeeding, or take prescription medication, please confirm any supplement with your GP, pharmacist or renal team before starting.

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