What tests are needed to confirm a diagnosis of fibronectin glomerulopathy?

definitive diagnosis requires a kidney biopsy showing characteristic fibronectin deposits in the glomeruli, usually confirmed by special staining or immunofluorescence. Genetic testing for pathogenic variants in the FN1 gene is also recommended to establish the inherited nature of the disease.

How often does fibronectin glomerulopathy recur after a kidney transplant, and how is recurrence detected?

Recurrence rates vary but can occur in 10–30% of cases. Post‑transplant surveillance involves regular urinalysis for proteinuria, serum creatinine checks, and, if indicated, a repeat kidney biopsy to detect early fibronectin deposition.

What lifestyle changes can help preserve kidney function in patients with fibronectin glomerulopathy?

Maintain a low‑salt diet, keep blood pressure below 130/80 mm Hg, avoid nephrotoxic medications (NSAIDs, certain antibiotics), stay hydrated, and limit alcohol. Regular exercise and weight control also support overall renal health.

What medications can help slow the progression of kidney damage in fibronectin glomerulopathy?

Blood pressure control with ACE inhibitors or ARBs is first‑line therapy to reduce proteinuria and protect renal function. Some clinicians may add low‑dose steroids or other immunosuppressants, but evidence is limited; close monitoring of kidney function is essential.

Fibronectin glomerulopathy

Fibronectin glomerulopathy is a rare inherited kidney disorder that progresses to end‑stage renal disease, often requiring transplantation.

Overview

Fibronectin glomerulopathy is a kidney disease that usually develops between early and mid‑adulthood but can occur at any age. It eventually leads to irreversible kidney failure (end‑stage renal disease).

Fifteen to 20 years following the appearance of signs and symptoms, individuals with fibronectin glomerulopathy often develop end‑stage renal disease. Affected individuals may receive treatment in the form of a kidney transplant; in some cases, fibronectin glomerulopathy comes back (recurs) following transplantation.

Fibronectin glomerulopathy is likely a rare condition, although its prevalence is unknown. At least 45 cases have been described in the scientific literature.

Symptoms

Blood in the urine (hematuria)
Excess protein in the urine (proteinuria)
High blood pressure (hypertension)
Renal tubular acidosis in some individuals

Causes & Risk Factors

Fibronectin glomerulopathy can be caused by mutations in the FN1 gene. The FN1 gene provides instructions for making the fibronectin‑1 protein. Fibronectin‑1 is involved in the continual formation of the extracellular matrix, which is an intricate lattice of proteins and other molecules that forms in the spaces between cells. During extracellular matrix formation, fibronectin‑1 helps individual cells expand (spread) and move (migrate) to cover more space, and it also influences cell shape and maturation (differentiation).

FN1 gene mutations lead to production of an abnormal fibronectin‑1 protein that gets deposited in the glomeruli of the kidneys, probably as the body attempts to . Even though there is an abundance of fibronectin‑1 in the glomeruli, the extracellular matrix that supports the blood vessels is weak because the altered fibronectin‑1 cannot assist in the matrix's continual formation. Without a strong cellular support network, the glomeruli are less able to filter waste. As a result, products that normally are retained by the body, such as protein and blood, get released in the urine, and acids are not properly filtered from the blood. Over time, the kidneys' ability to filter waste decreases until the kidneys can no longer function, resulting in end‑stage renal disease.

It is estimated that mutations in the FN1 gene are responsible for 40 percent of cases of fibronectin glomerulopathy. The cause of the remaining cases of this condition is unknown.

When fibronectin glomerulopathy is caused by mutations in the FN1 gene, it is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some of these cases, an affected person inherits the mutation from . Other cases result from in the gene and occur in people with no history of the disorder in their family. Some people who have the altered FN1 gene never develop the condition, a situation known as reduced penetrance.

Diagnosis

The kidneys of people with fibronectin glomerulopathy have large deposits of the protein fibronectin‑1 in structures called glomeruli. These structures are clusters of tiny blood vessels in the kidneys that . The waste products are then released in urine. The fibronectin‑1 deposits impair the glomeruli's filtration ability.

Treatment & Management

Management may involve kidney transplantation. In some cases, fibronectin glomerulopathy recurs after transplantation.

Other Names

Familial glomerular nephritis with fibronectin deposits
Familial lobular glomerulopathy
GFND
Glomerulopathy with fibronectin deposits
Glomerulopathy with giant fibrillar deposits

Additional Resources

Genetic Testing Information

Genetic Testing Registry: Glomerulopathy with fibronectin deposits 2

Genetic and Rare Diseases Information Center

Glomerulopathy with fibronectin deposits 1

Patient Support and Advocacy Resources

National Organization for Rare Disorders (NORD)

Catalog of Genes and Diseases from OMIM

GLOMERULOPATHY WITH FIBRONECTIN DEPOSITS 1; GFND1
GLOMERULOPATHY WITH FIBRONECTIN DEPOSITS 2; GFND2

Scientific Articles on PubMed

PubMed

References

Castelletti F, Donadelli R, Banterla F, Hildebrandt F, Zipfel PF, Bresin E, Otto E, Skerka C, Renieri A, Todeschini M, Caprioli J, Caruso RM, Artuso R, Remuzzi G, Noris M. Mutations in FN1 cause glomerulopathy with fibronectin deposits. Proc Natl Acad Sci U S A. 2008 Feb 19;105(7):2538-43. doi: 10.1073/pnas.0707730105. Epub 2008 Feb 11.
Ertoy Baydar D, Kutlugun AA, Bresin E, Piras R. A case of familial glomerulopathy with fibronectin deposits caused by the Y973C mutation in fibronectin. Am J Kidney Dis. 2013 Mar;61(3):514-8. doi: 10.1053/j.ajkd.2012.08.050. Epub 2012 Dec 6.
Otsuka Y, Takeda A, Horike K, Inaguma D, Goto N, Watarai Y, Uchida K, Mihatsch MJ, Joh K, Morozumi K. A recurrent fibronectin glomerulopathy in a renal transplant patient: a case report. Clin Transplant. 2012 Jul;26 Suppl 24:58-63. doi: 10.1111/j.1399-0012.2012.01644.x.
Yoshino M, Miura N, Ohnishi T, Suzuki K, Kitagawa W, Nishikawa K, Imai H. Clinicopathological analysis of glomerulopathy with fibronectin deposits (GFND): a case of sporadic, elderly-onset GFND with codeposition of IgA, C1q, and fibrinogen. Intern Med. 2013;52(15):1715-20. doi: 10.2169/internalmedicine.52.0046. Epub 2012 Mar 1.