The PAICS gene helps cells make purines, the small building blocks needed for DNA, RNA, and energy transfer. The protein made by this gene helps your cells grow, divide, and repair themselves. If the PAICS gene does not work properly, cells may struggle to make enough of these building blocks, which can lead to rare inherited conditions that affect growth, brain development, and other organs. Most people only hear about PAICS through genetic testing or specialist care.
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 hold the instructions for producing proteins, which are the working parts of cells. Other genes mainly help regulate when certain processes happen, where they take place, and how strongly they run. Taken together, genes affect how the body develops and functions, and they can also influence how you respond to food, stress, or medications. For a more detailed look at this topic, you can find additional information in the LearnHub.
Overview
PAICSGene function
What if the gene works
The PAICS gene helps cells make purines, key building blocks for DNA, RNA, and energy molecules. This supports normal growth, cell division, and tissue repair.
Risk
What if the gene does not work
Pathogenic variants in the PAICS gene can cause a rare condition with developmental delay or intellectual disability, growth problems, and brain or physical differences. Milder and more severe variants can change when features begin and how strongly they affect a person.
Treatment
What does that mean for your treatment
No PAICS-specific treatment or drug selection approach is currently established for pathogenic or loss-of-function variants in the PAICS gene. In research settings, PAICS is being studied as a possible drug target in some cancers, but this has not led to guideline-based treatment for people carrying inherited PAICS variants.
Gene function
What if the gene works
Your cells need a steady supply of certain chemical building blocks to copy DNA, make RNA, and power everyday activity. The PAICS gene helps produce some of these building blocks, called purines, through the body's main pathway for making them from scratch. A main part of what the PAICS gene does in the body is support this steady purine supply.
Inside your cells, the PAICS gene helps build purines from simple starting materials. Purines are basic parts of DNA, RNA, and several molecules your cells use every day.
Its protein carries out two consecutive chemical steps in the purine making pathway. Keeping these steps together helps cells produce purines in a smooth, efficient way.
The purines supported by the PAICS gene are used to make DNA and RNA. This lets cells copy genetic information and create RNA instructions for building proteins.
Purines also become part of ATP and GTP, molecules that carry energy and help cells send signals. This supports routine cell work such as movement, growth, and communication.
What is a variant?
A genetic variant is a small difference in the DNA sequence of a gene. These differences are common and help shape normal human diversity, including variation in appearance, metabolism, and how the body responds to environmental influences. Many have no 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 PAICS gene can change the shape or stability of the PAICS protein, reducing how well cells make purines, the building blocks needed for DNA and RNA. Some variants leave partial activity, while more disruptive variants can sharply lower or stop enzyme function, leading to a stronger cellular effect. This helps explain how variants influence the PAICS gene's function and why severe variants in both copies are linked to earlier and broader features in a rare developmental condition.
How variants are linked to conditions
Pathogenic variants in the PAICS gene can cause a very rare inherited developmental condition, often called PAICS deficiency. People with this diagnosis may have developmental delay or intellectual disability, seizures, poor growth, small head size, and other differences present from birth that can affect the eyes, hearing, heart, kidneys, or limbs. Among PAICS gene variants linked to health conditions, this is the main well-established association, and it usually appears when a person inherits two pathogenic variants, one from each parent.
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. In many genes, carrying a variant associated with a condition points to a possible link rather than a definite diagnosis, especially when more than one gene and environmental factors are involved. In some situations, though, 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?
There is not yet broadly confirmed evidence on specific factors that increase or reduce health risks related to the PAICS gene. Personal risk can still vary based on the exact gene change, family history, and the health condition being considered, so concerns about individual risk are best discussed with a doctor or genetic counselor.
Inheritance of PAICS variants
PAICS-related conditions that have been clearly described so far follow an autosomal recessive inheritance pattern. This means a child usually inherits one PAICS gene variant from each parent, and the parents are typically healthy carriers. When both parents carry a variant in the PAICS gene, each pregnancy has a 25% chance of the child inheriting both variants, a 50% chance of being a carrier, and a 25% chance of inheriting neither variant. In practical terms, PAICS gene inheritance usually means the condition appears only when both copies of the gene are affected.
What does my PAICS result mean for my family?
Changes in the PAICS gene linked to disease are passed down in families in a recessive pattern. For family members, this usually means parents may be healthy carriers, and brothers or sisters could also be affected or be carriers. Other relatives may also carry the same PAICS change, especially on the same side of the family.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for the PAICS gene looks for changes in your DNA, usually from a blood sample or saliva sample. This kind of PAICS genetic testing for variants reads the gene's code to see whether a variant is present and whether the result helps explain a diagnosed or suspected inherited condition.
When should I consider getting a genetic test?
Genetic testing for the PAICS gene may be considered when a child has a pattern of unexplained early developmental problems, such as delayed milestones, seizures, poor growth, or brain differences seen on scans, especially if similar findings run in the family. Testing can help show whether a PAICS-related condition is the cause.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but how much it reveals varies by the condition and the specific type of variant. Many factors, including lifestyle, environment, age, and medical history, influence how the body functions over time. For some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is most useful when considered with 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 in context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. This helps explain why the same treatment works well for one person but less well for another, or why some people are more sensitive to side effects. Small differences in genes can change how the body breaks down a drug, moves it through the body, or responds to it at its target. These differences are common and are one of several reasons medication response can vary from person to person.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences can shape the way a person responds to medications. It studies links between genes and drugs to help explain why the same treatment may work differently from one person to another. For many medicines, genes affect either how strongly a drug works or how the body handles it. This information can help guide treatment choices that are more informed and more personalized. More detail on this topic is available in the LearnHub.
Drugs influenced by the PAICS gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding routine medication decisions. If you have concerns about side effects, an unexpected response to treatment, or how your medicines fit with your overall health, talk with your doctor or pharmacist.
History
PAICS came into view as researchers mapped the genes involved in making purines, the building blocks cells need to grow and divide. In the 1990s, scientists identified and characterized the PAICS gene in humans as part of this wider effort to understand basic cell metabolism. Building on this early work, scientists uncovered more about the gene by comparing it with similar genes in yeast, bacteria, and other species. That work helped place PAICS within a long conserved pathway shared across life. Later, rare inherited variants in the PAICS gene were linked to a human developmental condition, which gave the gene added clinical relevance. Today, PAICS is known mainly through this path from basic laboratory discovery to medical genetics.