The ACTRT1 gene helps make a protein that supports the primary cilium, a tiny hair-like structure on cells that helps guide skin and hair development. If this gene does not work properly, cell signaling can become less controlled. Pathogenic variants in the ACTRT1 gene can cause Bazex-Dupré-Christol syndrome, which may include sparse hair, small skin pits, and a higher chance of skin cancers called basal cell carcinomas. Unlike BRCA1, the ACTRT1 gene is not widely known outside specialist care.
What is a gene?
A gene is a stretch of DNA that carries instructions your cells use to make molecules or direct activities in the body. Some genes provide the code for proteins, which do much of the cell’s work. Others mainly regulate 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 influence how you respond to food, stress, and medications. For a deeper look at this topic, you can find more in the LearnHub.
Overview
ACTRT1Gene function
What if the gene works
The ACTRT1 gene helps make a protein that supports primary cilia, tiny hairlike structures on cell surfaces. These structures help cells sense signals that guide normal skin, hair follicle, and tissue development.
Risk
What if the gene does not work
ACTRT1 gene variants can cause Bazex-Dupré-Christol syndrome, with sparse hair, small skin pits, and an increased chance of basal cell skin cancer. Milder or more severe variants can affect when signs appear and how noticeable they are.
Treatment
What does that mean for your treatment
For pathogenic variants in the ACTRT1 gene, no treatment or management approach specific to this gene is currently established. ACTRT1 is being studied in skin cancer research, where reduced gene activity may affect cell growth signals linked to basal cell carcinoma.
Gene function
What if the gene works
ACTRT1 helps cells build and support a tiny surface structure called the primary cilium. This cilium acts like a sensing antenna, helping cells notice and respond to signals around them. This helps explain what the ACTRT1 gene does in the body during routine cell sensing and organization.
The ACTRT1 gene helps cells assemble the primary cilium, a tiny antenna-like projection on the cell surface. Its protein gathers near the cilium base and supports the steps that let this structure form properly.
By supporting the cilium, the ACTRT1 gene helps cells receive and organize signals from their surroundings. This steady signaling supports normal cell behavior as cells grow, settle into place, and mature.
Its protein is part of the cell's inner support system, which helps anchor the cilium at the cell surface. This keeps the sensing structure connected to the cell's shape and layout.
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 have any noticeable effect and are simply part of natural genetic variation. Sometimes, though, a variant can change how a gene functions more significantly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the ACTRT1 gene often reduce or eliminate the ARP-T1 protein, making it unstable or shortened and disrupting primary cilia, the tiny cell surface structures that help control cell signaling. Milder changes may leave some activity, while more severe variants can stop most protein production, which helps explain how ACTRT1 gene variants affect protein function and why linked skin and hair changes may appear earlier or be more noticeable in some families.
How variants are linked to conditions
Pathogenic variants in the ACTRT1 gene cause Bazex-Dupré-Christol syndrome, a rare inherited skin condition. People with ACTRT1 gene variants linked to Bazex-Dupré-Christol syndrome may have sparse hair, small dents in the skin, especially on the backs of the hands, and a higher chance of developing basal cell skin cancers, often from a young age. In affected families, finding a disease-causing ACTRT1 variant can confirm the diagnosis.
A variant is not necessarily a diagnosis
Genetic variants are a routine feature of human biology and are widely found across the population. Most do not directly affect health and instead represent part of normal human variation. For many genes, having a variant associated with a condition points to a possible link rather than a confirmed diagnosis, particularly when several genes and environmental influences 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 ACTRT1, the main health risk linked to harmful changes is a higher chance of developing certain skin cancers, especially with long-term sun or ultraviolet exposure. Sun protection and regular skin checks can help with early detection and may lower added skin damage. Family history can also affect how risk shows up across relatives.
Inheritance of ACTRT1 variants
When people look into ACTRT1 inheritance, the best established pattern is X-linked dominant for ACTRT1-related Bazex-Dupré-Christol syndrome. A parent carrying a variant in the ACTRT1 gene can pass it to either sons or daughters, because the ACTRT1 gene is on the X chromosome. Features can vary within the same family, and they are often more noticeable in males.
What does my ACTRT1 result mean for my family?
For ACTRT1, a disease-causing result can run in families in an X-linked dominant pattern. Close relatives on the same side of the family may also carry the change and could have related skin features or a higher chance of basal cell skin cancers. If a parent carries the variant, each child has a 1 in 2, or 50%, chance of inheriting it.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for variants in the ACTRT1 gene usually uses a blood or saliva sample, and the lab reads the DNA code to look for changes. It can show whether a variant in the ACTRT1 gene is present, but a result may be clearly health related, uncertain, or no relevant variant may be found.
When should I consider getting a genetic test?
Consider ACTRT1 genetic testing if you or close relatives have had repeated basal cell skin cancers at a young age, especially along with lifelong sparse hair or small pitted marks on the skin. Testing can help confirm an inherited skin condition linked to ACTRT1 and clarify whether it may run in the family.
A genetic result is only one part of your health story
Genetic results can be informative, but how much they reveal depends on the condition and the kind of variant involved. Over time, factors such as lifestyle, environment, age, and medical history also shape how the body works. For some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is best understood together with other parts of care. In other situations, a genetic result may give 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 your body responds to medicines. Some people break down a drug faster or slower than expected, while others may be more or less sensitive to its effects. This helps explain why the same treatment can work well for one person, seem less effective for another, or cause more side effects in someone else.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect a person’s response to medications. It looks at 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 both how strongly a drug works and how the body processes it. This information can help support more informed, individualized treatment decisions. To explore this topic in greater detail, you can learn more in the LearnHub.
Drugs influenced by the ACTRT1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication response, so general health concerns or questions about medicines are best discussed with your doctor.