The HR gene helps control the normal cycle of hair growth and supports healthy skin. If you carry a disruptive variant in this gene, hair may be very sparse from infancy or be lost early and not grow back, and small skin bumps can appear over time. In medicine, the HR gene is best known for its link to a rare inherited form of permanent hair loss called atrichia with papular lesions.
What is a gene?
Genes are stretches of DNA that provide cells with instructions for making molecules or for regulating processes in the body. Some genes hold the information needed to make proteins, the parts of cells that do much of the work. Others are mainly involved in controlling when certain processes happen, where they take place, and how strongly they run. As a group, genes influence how the body develops and functions, and they can also shape how you respond to food, stress, or medications. To explore this subject in more detail, you can find more in the LearnHub.
Overview
HRGene function
What if the gene works
The HR gene helps control the normal growth cycle of hair follicles. It also supports healthy skin by helping skin cells switch genes on and off at the right time.
Risk
What if the gene does not work
Pathogenic variants in the HR gene mainly cause hair loss that starts soon after birth and may progress to near-complete scalp and body hair loss; some people later develop small skin bumps. Milder and more severe variants can change timing and extent.
Treatment
What does that mean for your treatment
For a pathogenic loss-of-function variant in the HR gene, no gene-specific treatment or drug choice is currently established. The HR gene is mainly being studied to better understand hair follicle biology, rather than as a current treatment target.
Conditions associated with HR
Gene function
What if the gene works
Hair follicles do not grow constantly. They follow a repeating cycle, and the HR gene helps keep that cycle organized by controlling when other genes are active. This supports normal remodeling of the follicle after each phase. It also helps explain what the HR gene does in normal hair growth.
Inside certain skin and follicle cells, the HR gene acts like a dimmer switch for selected genes. This helps keep growth and renewal programs on the right schedule.
Hair follicles use the HR gene to move through growth, rest, shedding, and regrowth in an orderly rhythm. This timing supports normal hair growth across repeated cycles.
After a growth phase ends, the HR gene helps the follicle reshape itself for the next cycle. This reset prepares the follicle to produce a new hair.
The HR gene helps cells fine tune gene activity in response to body signals, including vitamin D and thyroid related signals. This coordination supports routine function in hair follicles and nearby skin.
What is a variant?
A genetic variant is a minor change in the DNA sequence within a gene. These changes are common and form part of normal human diversity, including differences in appearance, metabolism, or how the body responds to environmental influences. Many variants have no noticeable effect and simply represent natural genetic variation. Sometimes, however, a variant can change the function of a gene more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Many variants in the HR gene make the HR protein too short, unstable, or unable to control other genes in hair follicle cells. More disruptive changes often leave little or no working protein. Milder variants may preserve some activity, which helps explain how HR gene variants affect hair growth. In people with HR related hair loss, stronger loss of function is often linked to earlier and more complete scalp and body hair loss.
How variants are linked to conditions
Pathogenic variants in the HR gene cause atrichia with papular lesions, a rare inherited hair loss condition where people lose scalp and body hair soon after birth and may later develop small skin bumps. This is a well-established link. When someone has the typical features and two pathogenic variants in the HR gene are found, the result can confirm the diagnosis.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are widely found in the general population. Most do not have a direct effect on health and simply reflect natural human diversity. For many genes, carrying a variant associated with a condition indicates a possible link rather than a definite diagnosis, especially when multiple genes and environmental factors also play a part. In some situations, though, a single well-characterized variant in a specific gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For HR, risk is mainly shaped by genetics rather than lifestyle. A child is affected when both parents pass on a changed HR gene, so family history and whether both parents are carriers matter most. There is not enough evidence to say that diet, stress, or everyday habits change this risk.
Inheritance of HR variants
HR-related hair loss conditions are most often inherited in an autosomal recessive pattern, especially atrichia with papular lesions linked to the HR gene. This means a child inherits one HR gene variant from each parent. Parents are usually healthy carriers, and when both carry a variant, each pregnancy has a 25% chance of an affected child, a 50% chance of a carrier child, and a 25% chance of a child without the familial variant. Because HR is on a non-sex chromosome, this inheritance pattern is the same for boys and girls.
What does my HR result mean for my family?
For families with a disease-causing change in the HR gene, the pattern is usually recessive, which means close relatives may also be carriers even if they do not have hair loss. Brothers and sisters could also be affected if they inherited the same kind of change from both parents. Family members may want to learn whether the same gene change runs in the family, especially when there is a history of very sparse hair or early complete hair loss.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant, genetic testing for variants in the HR gene uses DNA from a blood sample or cheek swab. A laboratory reads the gene’s DNA spelling and compares it with the usual pattern. Results may identify a known family variant or another change that helps clarify a diagnosis.
When should I consider getting a genetic test?
Testing for changes in the HR gene may be worth considering when a baby or young child loses scalp and body hair very early in life and it does not grow back, especially if small skin bumps appear later or similar hair loss runs in the family. A result can help confirm the cause and clarify the chance of it happening again in a family.
A genetic result is only one part of your health story
Genetic results can provide valuable insight, but how much they show depends on the condition and the type of variant involved. Many other influences, including lifestyle, environment, age, and medical history, affect how the body works over time. In 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, these 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 DNA can influence how the body breaks down a drug, moves it through the body, or responds to it at its target, so the same treatment may work better for one person than another. These differences are common and can shape how much benefit someone gets from a medication or how sensitive they are to side effects.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect the way people respond to medications. It looks at gene and drug patterns to better understand why the same treatment may work differently from one person to another. For many medicines, genes can influence both how strong a drug’s effects are and how the body processes it. This information can help support more informed and individualized treatment decisions. To explore this subject in more detail, you can learn more in the LearnHub.
Drugs influenced by the HR gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication choice or dosing. If you have concerns about side effects, medicine changes, or your overall health, talk with your doctor or pharmacist.
History
Throughout history, people have described families in which children lost scalp and body hair soon after birth, long before the cause was understood. In the 20th century, similar patterns in people and in “hairless” laboratory mice drew scientific attention to an inherited cause. Researchers later mapped this condition to chromosome 8 and identified the HR gene in the 1990s as the key gene involved in several forms of inherited hair loss, especially atrichia with papular lesions. Building on this early work, scientists recognized that some people once thought to have alopecia areata actually had HR-related inherited hair loss instead. That shift improved diagnosis and helped families receive clearer genetic answers.