The UQCC2 gene helps your cells build complex III, part of the mitochondria’s energy making system. If this gene does not work properly, cells may produce less energy, which can lead to a rare mitochondrial condition with muscle weakness, feeding or growth problems, developmental delay, lactic acid buildup in the blood, and sometimes heart or liver involvement. Symptoms often begin in infancy or childhood, but the pattern and severity can vary from person to person.
What is a gene?
Genes are stretches of DNA that give your cells instructions for making molecules or regulating activities in the body. Some genes carry the code for proteins, which are the parts of cells that do much of the work. Other genes mostly control when certain activities happen, where they happen, and how strong they are. Together, genes affect how the body develops and works, and they can influence how you respond to food, stress, or medications. For a closer look at this topic, you can find more in the LearnHub.
Overview
UQCC2Gene function
What if the gene works
The UQCC2 gene helps mitochondria build a key part of the cell's energy system. This supports steady energy production, especially in muscles and the brain.
Risk
What if the gene does not work
UQCC2 gene variants can reduce energy production and cause a rare mitochondrial condition called complex III deficiency. Effects include lactic acidosis, low muscle tone, feeding problems, and delayed development. Milder or more severe variants can shift symptom timing and severity.
Treatment
What does that mean for your treatment
No UQCC2-specific treatment or drug-choice approach is currently established for people with a pathogenic or loss-of-function variant in the UQCC2 gene. Care is supportive and based on the person’s symptoms and organ involvement, rather than on a gene-directed medicine.
Conditions associated with UQCC2
Gene function
What if the gene works
Your cells need a steady way to turn oxygen and nutrients into usable energy. The UQCC2 gene supports this work inside mitochondria, the small structures that power each cell. When it works properly, cells can carry out cell energy production in mitochondria by building an important part of the energy chain.
UQCC2 helps build complex III, an essential part of the mitochondrial energy chain. It works with other helper proteins so this structure is put together in the right order.
Inside mitochondria, UQCC2 helps a core building block called cytochrome b stay stable while it is being made and fitted into complex III. This careful step helps the energy system form correctly.
By helping assemble complex III, UQCC2 supports the flow of electrons that drives ATP production, the cell's main usable fuel. This helps tissues with constant energy needs keep running day to day.
What is a variant?
A genetic variant is a small difference in the DNA sequence of a gene. These changes are common and help shape normal human diversity, including differences in appearance, metabolism, and how the body responds to environmental influences. Many variants do not cause any noticeable effect and simply reflect 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
Many UQCC2 gene variants lower the amount of UQCC2 protein or make it unstable, so mitochondria cannot build complex III, part of the cell's energy system, properly. Milder changes may leave some activity, while more disruptive variants can nearly abolish function and may also destabilize the related UQCC1 protein. This helps explain how UQCC2 gene variants affect mitochondria, with partial loss often linked to less severe impairment and near-complete loss to earlier, more severe complex III deficiency.
How variants are linked to conditions
Pathogenic variants in both copies of the UQCC2 gene cause mitochondrial complex III deficiency, nuclear type 5, a rare inherited condition. Signs often start in infancy and may include poor feeding, low muscle tone, high lactic acid levels, developmental delay, and sometimes liver or heart problems. This is the main well-established condition linked to the UQCC2 gene, and severity can vary from one person to another.
A variant is not necessarily a diagnosis
Genetic variants are a common and expected part of human biology across the general population. Most do not directly affect health and simply reflect natural differences among people. For many genes, having a variant associated with a condition points to a possible link rather than a clear diagnosis, particularly when several genes and environmental influences also play a role. In other situations, though, one well-understood variant in a particular gene is enough to establish a diagnosis.
Are there things that can increase or change my risk?
For UQCC2, risk is mainly shaped by genetics, especially whether someone inherits harmful changes in both copies of the gene. There is not broadly confirmed evidence that lifestyle or environmental factors meaningfully increase or reduce the chance of a UQCC2-related condition.
Inheritance of UQCC2 variants
UQCC2-related conditions are inherited in an autosomal recessive pattern. This means a person usually develops the condition only when they inherit two disease-causing variants in the UQCC2 gene, one from each parent. Parents who each carry one variant are typically healthy carriers, and with each pregnancy they have a 25% chance of having an affected child, a 50% chance of having a child who is also a carrier, and a 25% chance of having a child with neither variant. In practical terms, how UQCC2 gene variants are inherited means the condition can appear in brothers or sisters even when neither parent has symptoms.
What does my UQCC2 result mean for my family?
Changes in the UQCC2 gene are linked to a rare inherited condition that usually runs in families in a recessive pattern. For family members, this often means parents may be healthy carriers, and brothers or sisters could also be affected or be carriers. More distant relatives may also carry the same gene change, especially on the same side of the family.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the UQCC2 gene, genetic testing uses DNA from a blood sample or cheek swab. Genetic testing for UQCC2 variants is often part of a multigene panel, exome sequencing, or genome sequencing, and the lab compares your DNA with a reference sequence to classify any change.
When should I consider getting a genetic test?
Genetic testing may be worth considering if a baby or child has signs of a rare inherited energy-production condition, such as severe weakness, feeding problems, developmental delay, or repeated episodes of high lactic acid, especially if similar problems run in the family. UQCC2 is usually checked as part of a broader genetic test for suspected mitochondrial disease.
A genetic result is only one part of your health story
A genetic result can provide valuable insight, but what it reveals depends on the condition and the specific type of variant involved. Over time, many factors influence how the body works, including lifestyle, environment, age, and medical history. For some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is most useful when viewed alongside other parts of care. In other situations, a genetic result can offer a clear answer. In areas like medication response, genetic results can also help put personal experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Small differences in genes can change how the body absorbs, breaks down, transports, or responds to a drug, so the same treatment may work well for one person but less well for another. These inherited differences are common and can influence how much benefit someone gets from a medicine or how likely they are to notice side effects.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect a person’s response to medications. It studies relationships between genes and drugs to help explain why the same treatment can work differently from one person to another. For many medicines, genes influence either how strongly a drug works or how the body handles it. This information can support treatment decisions that are more informed and more individualized. More on this topic is available in the LearnHub.
Drugs influenced by the UQCC2 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting medication response, so questions about medicines, side effects, or your general health are best discussed with your doctor.