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NPHP1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

NPHP1 gene

The NPHP1 gene provides instructions for making the nephrocystin-1 protein, which is critical for cilia function and is associated with several kidney and multisystem disorders.

Normal Function

The NPHP1 gene provides instructions for making the nephrocystin-1 protein. This protein is thought to play a role in cell structures called cilia, which are microscopic, finger-like projections that stick out from the surface of cells. Cilia participate in signaling pathways that transmit information within and between cells and are important for the development and function of many types of cells and tissues.

Nephrocystin-1 is found at the base of cilia in cells of the kidneys, respiratory tract, and the light-sensitive tissue at the back of the eye (the retina). Although the specific function of nephrocystin-1 is not well understood, it is thought to interact with a number of other proteins as part of a large protein complex that may be important for normal cilia function.

Health Conditions Related to Genetic Changes

Nephronophthisis

At least 23 mutations in the NPHP1 gene have been found to cause a kidney disorder called nephronophthisis type 1. This condition is characterized by inflammation and scarring of the kidneys, ultimately leading to a life-threatening failure of kidney function known as end-stage renal disease (ESRD), which usually occurs around age 13.

  • The most common genetic change is a large deletion on chromosome 2 that removes the whole NPHP1 gene.
  • Other deletions or mutations that change single amino acids or lead to an abnormally short protein can also cause the condition.
  • It is thought that people with nephronophthisis type 1 have little or no functional nephrocystin-1, which impairs cilia function and disrupts important chemical signaling pathways.

Other disorders

Mutations in the NPHP1 gene can cause syndromes known as nephronophthisis-associated ciliopathies, including:

  • Senior-Løken syndrome: Characterized by the combination of nephronophthisis and retinal degeneration.
  • Joubert syndrome: A multisystem disorder that typically involves neurological problems, nephronophthisis, eye abnormalities, and liver disease.

Other Names for This Gene

  • JBTS4
  • juvenile nephronophthisis 1 protein
  • nephrocystin-1
  • nephronophthisis 1 (juvenile)
  • NPH1
  • SLSN1

Frequently Asked Questions

The most reliable test is a chromosomal microarray or targeted copy‑number analysis that can detect the common whole‑gene deletion. If a deletion is not found, sequencing of the NPHP1 coding regions (next‑generation sequencing panel for cystic kidney diseases) can identify point mutations or small indels.
Management focuses on slowing progression: strict blood pressure control (often with ACE inhibitors or ARBs), low‑salt diet, and avoidance of nephrotoxic drugs. Regular monitoring of renal function and electrolytes is essential. Once kidney function declines to <15 mL/min/1.73 m², dialysis or pre‑emptive kidney transplantation becomes the definitive therapy.
NPHP1 disease is autosomal recessive. Both parents of an affected child are obligate carriers. Each subsequent pregnancy carries a 25 % chance of being affected, a 50 % chance of being a carrier, and a 25 % chance of being unaffected and not a carrier. Carrier testing for parents and at‑risk siblings can be done with the same deletion‑specific assay, and prenatal or pre‑implantation genetic diagnosis is possible if desired.
Early clues include excessive nighttime urination, a gradual increase in blood pressure, growth retardation, and unexplained anemia. Urine tests may reveal low concentrating ability, and an ultrasound often shows small, echogenic kidneys with loss of corticomedullary differentiation.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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