The FBP1 gene helps the liver make glucose when you have not eaten for a while, which supports steady energy between meals. This gene plays an important role in helping the body switch to a backup fuel source during fasting. If both copies of the FBP1 gene do not work properly, a person can develop fructose-1,6-bisphosphatase deficiency, a rare inherited condition that may cause low blood sugar, acid buildup in the blood, and episodes of illness during fasting or infections. With careful management, many people can avoid these episodes.
What is a gene?
Genes are sections of DNA that carry information cells use to make molecules or to regulate processes in the body. Some genes provide the instructions for producing proteins, which are the parts of cells that do much of the work. Others mostly help determine when certain processes happen, where they happen, and how active they are. Taken together, genes affect how the body grows and works, and they can also influence how you respond to food, stress, or medications. For a deeper look at this topic, you can find more in the LearnHub.
Overview
FBP1Gene function
What if the gene works
The FBP1 gene helps the liver make glucose between meals. This supports steady blood sugar during fasting and helps the body use stored energy.
Risk
What if the gene does not work
When the FBP1 gene does not work properly, the body struggles to make glucose during fasting or illness, causing low blood sugar and lactic acidosis, often from infancy. Milder and more severe variants can change onset and severity.
Treatment
What does that mean for your treatment
Pathogenic or loss-of-function variants in the FBP1 gene guide treatment toward strict fasting avoidance and rapid glucose support during illness or poor intake. Many people also need limits on fructose, sucrose, and sorbitol because these can trigger metabolic crises. No FBP1-targeted drug is established, so care centers on diet planning and emergency glucose management.
Conditions associated with FBP1
Gene function
What if the gene works
Your body needs a steady glucose supply, especially between meals and overnight. The FBP1 gene helps liver and kidney cells make glucose from other stored materials when food is not coming in. This supports normal energy needs in everyday life.
The FBP1 gene provides instructions for a protein that carries out a key step in making new glucose. Its protein converts one sugar phosphate into another, allowing glucose production to keep moving.
By helping make glucose, this gene supports blood sugar balance when you have not eaten for several hours. This is part of how the FBP1 gene helps control blood sugar between meals and overnight.
When food is not coming in, the body shifts from using incoming sugar to making its own. Its activity helps liver and kidney cells use lactate, glycerol, and some amino acids as starting materials for glucose.
What is a variant?
A genetic variant is a small difference in the DNA sequence within a gene. These changes are common and help shape normal human diversity, including differences in appearance, metabolism, or how the body responds to environmental influences. Many variants do not cause any noticeable effects and simply represent natural genetic variation. In some situations, though, a variant can change how a gene functions more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the FBP1 gene can change the enzyme’s shape, make it less stable, or sharply reduce its activity, and how FBP1 gene variants affect the enzyme can range from mild impairment to almost complete loss of function. Some missense variants leave partial activity, while more disruptive variants, such as stop, splice, or frameshift changes, often lead to little or no working enzyme. In fructose-1,6-bisphosphatase deficiency, a greater loss of activity may be linked to earlier or more intense episodes.
How variants are linked to conditions
Disease-causing variants in the FBP1 gene cause fructose-1,6-bisphosphatase deficiency, the main condition linked to FBP1 gene variants. It can lead to episodes of very low blood sugar and acid buildup in the blood, often during fasting or illness. Symptoms usually begin in infancy or childhood, although severity varies. Finding disease-causing variants in both copies of the FBP1 gene can confirm the diagnosis.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are common across the general population. Most do not have a direct effect on health and simply reflect natural human diversity. For many genes, carrying a variant connected with a condition indicates a possible association rather than a definite diagnosis, especially when multiple genes and environmental factors are involved. In some situations, however, a single well-characterized variant in a specific gene can be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For FBP1, the main risk comes from inheriting two changed copies of the gene, one from each parent. In people living with FBP1-related illness, long fasts, infections, and high fructose intake can trigger low blood sugar and acid buildup. Avoiding these triggers can help prevent episodes, but it does not change the underlying genetic risk.
Inheritance of FBP1 variants
FBP1-related fructose-1,6-bisphosphatase deficiency follows an autosomal recessive inheritance pattern. This means a child inherits one altered copy of the FBP1 gene from each parent. Parents who each carry one variant usually do not have the condition themselves, but with each pregnancy they have a 25% chance of having an affected child, a 50% chance of having a child who is a carrier, and a 25% chance of having a child who inherits neither variant. In practical terms, FBP1 inheritance does not usually pass directly from one affected parent to every generation unless both parents carry a variant.
What does my FBP1 result mean for my family?
For FBP1, family members can sometimes carry the same gene change without having symptoms. Full brothers and sisters may also be affected or be carriers, so the result can matter for siblings as well as for future children in the family. Parents are often healthy carriers, and other relatives may want to learn whether the same change runs in the family.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for FBP1 gene variants uses a blood or saliva sample. A lab reads the DNA in the FBP1 gene to look for changes linked to fructose-1,6-bisphosphatase deficiency, which can help confirm a diagnosis and show whether close relatives may carry the same variant.
When should I consider getting a genetic test?
Genetic testing for the FBP1 gene may be worth considering if a baby or child has repeated episodes of severe low blood sugar, unusual sleepiness, fast breathing, or acid buildup in the body, especially during fasting or illness. It can also help when there is a family history of this rare inherited condition.
A genetic result is only one part of your health story
Genetic results can be informative, but what they can tell you varies with the condition and the kind of variant found. How your body functions over time is also shaped by many factors, including lifestyle, environment, age, and medical history. For some conditions, particularly those affected by many genes, genetic information offers context rather than certainty and makes the most sense when considered with the rest of your care. In other situations, a genetic finding may give a clear answer. For topics like medication response, genetic results can also help put personal experiences in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Small differences in DNA can change how the body absorbs, breaks down, or responds to a drug, so the same treatment may work better for one person than for another. These inherited differences are common and can influence both benefit and side effects, which is why medication response is not always the same across people.
What is Pharmacogenetics?
Pharmacogenetics is the area of study focused on how genetic differences affect response to medications. By examining links between genes and drugs, it helps explain why treatments can work differently from one person to another. For many medicines, genes influence both how strongly a drug works and how the body processes it. This information can support treatment decisions that are more informed and more individualized. You can read more about this topic in the LearnHub.
Drugs influenced by the FBP1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting how medicines will work, so general medication questions, side effects, or other health concerns are best discussed with your doctor.