The IDH3B gene helps your cells turn nutrients into usable energy inside mitochondria, the parts of cells that act as power sources. This gene plays an important role in the retina, the light sensing tissue at the back of the eye. If it does not work properly, some people develop an inherited retinal condition called retinitis pigmentosa, which often causes trouble seeing in dim light and a gradual narrowing of side vision. IDH3B is mainly known in medical genetics rather than in popular culture.
What is a gene?
Genes are stretches of DNA that carry instructions your cells use to make molecules or direct processes in the body. Some genes provide the code for proteins, which are the cell’s working parts. Others are involved mainly in regulating when certain processes happen, where they happen, and how strongly they occur. Taken together, genes affect how the body grows and works, and they can influence how you respond to food, stress, or medicines. For a more detailed look at this topic, you can find more in the LearnHub.
Overview
IDH3BGene function
What if the gene works
The IDH3B gene helps mitochondria turn nutrients into usable energy. Its protein is part of an enzyme in the citric acid cycle, a core process many cells use to power everyday activity.
Risk
What if the gene does not work
Certain variants in the IDH3B gene are linked to retinitis pigmentosa, causing night blindness and a narrowing field of vision. Milder or more severe variants can affect when symptoms begin and how much vision changes.
Treatment
What does that mean for your treatment
No treatment or management approach is currently established that is specific to pathogenic variants in the IDH3B gene.
Conditions associated with IDH3B
Gene function
What if the gene works
Your cells need a steady way to turn food into usable energy. Inside the energy-making parts of cells, called mitochondria, the IDH3B gene helps support a key step in the citric acid cycle, which is a chain of reactions cells use to release energy from food. This helps explain what the IDH3B gene does in everyday cell energy production.
The IDH3B gene helps build an enzyme that carries out a key reaction in the cell’s main energy pathway. This keeps energy moving out of nutrients in a controlled, steady way inside mitochondria.
During this reaction, the enzyme helps produce NADH, an energy carrier your cells use to help make ATP, the cell’s main fuel. That supports routine energy needs across many tissues.
IDH3B provides one part of a larger enzyme, so it works closely with other protein pieces rather than alone. This coordination helps the energy pathway run smoothly as cells meet day to day demands.
What is a variant?
A genetic variant is a minor change in a gene’s DNA sequence. These changes are common and are part of normal human diversity, including differences in appearance, metabolism, and the way the body responds to environmental influences. Many variants do not have any noticeable effect and simply represent natural genetic variation. In some cases, though, a variant can change how a gene works more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the IDH3B gene can change the protein’s shape, stability, or ability to join its partner subunits in mitochondria, which lowers enzyme activity. Milder changes may leave some activity in place, while more disruptive variants, including some truncating or splice variants, can greatly reduce or nearly eliminate it. In IDH3B gene variants linked to retinitis pigmentosa, this functional drop may influence how early vision changes start and how marked they become.
How variants are linked to conditions
Pathogenic variants in both copies of the IDH3B gene cause a rare inherited eye condition called retinitis pigmentosa, often described as IDH3B-related retinitis pigmentosa. People with this diagnosis usually notice night blindness first, then gradual loss of side vision, with central vision sometimes becoming affected later. This is an autosomal recessive condition, so the diagnosis is typically confirmed when two disease-causing IDH3B variants are identified.
A variant is not necessarily a diagnosis
Genetic variants are common across the general population and are a normal part of human biology. Most do not directly affect health and instead represent natural human diversity. For many genes, having a variant associated with a condition suggests a possible link rather than a definite diagnosis, especially when several genes and environmental factors are involved. In some situations, though, one well-characterized variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For IDH3B-related eye disease, risk is mainly shaped by inheritance, especially whether someone is born with changed copies from both parents. There is not broadly confirmed evidence that lifestyle or everyday environmental factors meaningfully increase or reduce this genetic risk.
Inheritance of IDH3B variants
IDH3B-related conditions that are clearly established in human genetics are inherited in an autosomal recessive pattern. In practical terms, this means a child usually inherits one IDH3B variant from each parent, and the parents are typically healthy carriers. When both parents carry an IDH3B variant, each pregnancy has a 25% chance of the child inheriting both altered copies, a 50% chance of being a carrier, and a 25% chance of inheriting neither variant. This is the main pattern seen when looking at how IDH3B variants are inherited in families.
What does my IDH3B result mean for my family?
For families with an IDH3B-related eye condition, this usually means relatives on both sides can carry the changed gene without having symptoms. Brothers and sisters may also be affected or may be carriers, so family members may want to learn whether the same result is present in them. Children of someone with an IDH3B-related condition will usually be carriers unless the other parent also carries a changed copy of IDH3B.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the IDH3B gene, genetic testing for IDH3B variants reads DNA from a blood, saliva, or cheek swab sample. The lab checks the gene’s code for specific variants and reports whether a variant was found.
When should I consider getting a genetic test?
Genetic testing for the IDH3B gene may be worth considering if you or your child has an inherited retina condition, especially night blindness, slowly worsening side vision, or a family history of similar vision loss. Testing can help show whether an IDH3B change is part of the cause.
A genetic result is only one part of your health story
A genetic finding can provide meaningful information, but what it reveals depends on the condition and the type of variant involved. Many other factors, including lifestyle, environment, age, and medical history, also shape how the body works over time. In some conditions, especially those influenced by many genes, genetic information adds context rather than certainty and is best understood alongside other parts of care. In other situations, a genetic result may offer a clear answer. In areas like medication response, genetic results can also help put individual experiences into perspective.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Small differences in a person’s DNA can change how the body breaks down a drug, moves it through the body, or responds at the target the drug is meant to affect. This helps explain why the same treatment works well for some people, works less well for others, or causes more side effects in some than in others.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes affect the way they respond to medications. By looking at patterns between genes and drugs, it helps explain why the same treatment can work differently from one person to another. For many medicines, genes influence either how the body handles a drug or how strong its effects are. This information can support more informed, personalized treatment choices. More detail on this topic is available in the LearnHub.
Drugs influenced by the IDH3B gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choices, so general questions about your medicines, side effects, or overall health are best discussed with your doctor.