GENE REFERENCE / HGNC:3680

FGF23

fibroblast growth factor 23

protein-coding gene12p13.32Gene information

What does this gene do?

The FGF23 gene provides instructions for making a protein called fibroblast growth factor 23, which is produced in bone cells. This protein helps regulate phosphate levels within the body. Among its many functions, phosphate plays a critical role in the formation and growth of bones during childhood and helps maintain bone strength in adults.

Fibroblast growth factor 23 works in the kidneys to keep the body's phosphate levels in balance. The kidneys normally release excess phosphate in the urine, and they reabsorb this mineral into the bloodstream when more is needed. Fibroblast growth factor 23 acts as a signal that tells the kidneys to stop reabsorbing phosphate into the bloodstream.

In order for fibroblast growth factor 23 to function, sugar molecules must attach to the protein through a process called glycosylation. This allows fibroblast growth factor 23 to move out of the bone cell and protects it from being broken down. Once outside the cell, fibroblast growth factor 23 must bind to a receptor protein that spans the membrane of kidney cells. Binding to this receptor triggers a signaling pathway that stops phosphate reabsorption by the kidneys. When more phosphate is needed, fibroblast growth factor 23 is cut (cleaved) at a certain site, which turns off (inactivates) the protein. This helps regulate the amount of active fibroblast growth factor 23 that is circulating in the bloodstream.

Source: MedlinePlus, National Library of Medicine. Source publication: 2026-03-16. Source review: 2026-03.

ClinGen reviews

We found no matching ClinGen review in the data used here. This does not rule out a link between the gene and a condition.

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 340
Submissions for variants in or overlapping this gene: 530
Submissions explicitly reporting this gene: 448
Alleles reported pathogenic / likely pathogenic: 14
VariationIDs with uncertain significance: 168
VariationIDs with conflicting classifications: 15

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about FGF23?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 14 alleles in FGF23 reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in FGF23.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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