The PRL gene gives your body instructions to make prolactin, a hormone that helps the breasts prepare for and make milk after pregnancy. This gene plays an important role in signaling that also supports menstrual cycles, fertility, and other body functions. If the PRL gene does not work properly, some people may have trouble with milk production, changes in periods, or fertility problems. PRL is best known in everyday care because prolactin levels are often checked when doctors are looking into missed periods or unexpected breast milk production.
What is a gene?
Genes are stretches of DNA that hold instructions your cells use to make molecules or to regulate 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 are used mainly to guide when certain processes happen, where they happen, and how strongly they are carried out. Together, genes affect how the body develops and works, and they can also influence how you respond to food, stress, or medications. For a deeper look at this topic, you can find more in the LearnHub.
Overview
PRLGene function
What if the gene works
The PRL gene provides instructions for prolactin, a hormone best known for helping breast tissue make milk after childbirth. It also supports reproductive hormone signaling and can influence immune system activity.
Risk
What if the gene does not work
Variants in the PRL gene can cause isolated prolactin deficiency, often leading to little or no breast milk after childbirth. Milder variants may partly lower prolactin, while more severe variants can also affect menstrual cycles or fertility.
Treatment
What does that mean for your treatment
No treatment or management approach specific to pathogenic or loss-of-function variants in the PRL gene is currently established. The PRL gene and prolactin signaling are being studied as possible biomarkers or drug targets in some cancers, but this has not led to routine treatment decisions based on PRL variants.
Gene function
What if the gene works
During pregnancy and after birth, your body uses the PRL gene to support the changes needed for feeding a baby. It helps make prolactin, a hormone messenger released mainly by the pituitary gland in the brain. This signaling is part of normal breast preparation and ongoing milk production.
The PRL gene provides instructions for prolactin, a hormone messenger released into the bloodstream. It helps tissues respond to normal changes linked to pregnancy, breastfeeding, and reproductive timing.
Prolactin helps breast tissue mature during pregnancy so it is ready to make milk after birth. It supports the normal growth and activity of milk making cells.
After childbirth, prolactin helps switch on and maintain milk production. This is a central part of what the PRL gene does in the body, helping the breasts respond to regular nursing or pumping.
What is a variant?
A genetic variant is a minor change in a gene’s DNA sequence. These changes are common and help explain normal differences among people, including appearance, metabolism, and the way the body responds to environmental influences. Many variants do not cause any noticeable effects and are simply part of natural genetic diversity. Sometimes, though, a variant changes how a gene works more significantly and can contribute to, or directly cause, a genetic condition.
Genetic variants
What if the gene does not work
Variants in the PRL gene can change how much prolactin is made, how stable the protein is, or how well it is released from cells. This is how PRL gene variants affect prolactin production at a molecular level: some variants slightly alter gene activity, while more disruptive variants can markedly reduce protein formation or change its shape. In some cases, variants in regulatory parts of the PRL gene may also shift how strongly the gene is switched on.
How variants are linked to conditions
The PRL gene does not yet have a broadly confirmed link to a specific health condition in routine clinical genetics, and evidence on the PRL gene variants linked to conditions is still developing. If you carry a reported variant in the PRL gene, its meaning is usually interpreted together with your symptoms, hormone test results, and family history.
A variant is not necessarily a diagnosis
Variants in genes are a usual part of human biology and are widely found across the population. Most do not directly affect health and simply reflect natural human diversity. 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 play a role. 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?
There isn’t yet broadly confirmed evidence on specific factors that increase or reduce health risk specifically related to the PRL gene. Anyone with concerns about their personal or family risk can speak with a doctor or genetic counselor.
Inheritance of PRL variants
There is not yet a broadly confirmed, disease-specific Mendelian pattern for how PRL gene variants are inherited, and current evidence does not support describing PRL as clearly autosomal dominant or autosomal recessive for a well-established PRL-related condition. In practical terms, how PRL gene variants are inherited is still being clarified as research develops. The PRL gene is located on chromosome 6, which is an autosome, so you inherit one copy from each parent.
What does my PRL result mean for my family?
There isn't yet a broadly confirmed inheritance pattern tied to a specific health condition for the PRL gene, though this understanding can change as research develops. If you have a specific PRL result and questions about what it could mean for your family, a doctor or genetic counselor can help explain it in the context of your personal and family history.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a change in the PRL gene, a lab can do genetic testing for PRL gene variants using a blood sample or cheek swab. The test reads the gene's DNA code and checks for variants, then a report explains whether a change was found and whether it is known to be linked with health effects.
When should I consider getting a genetic test?
There is not a broadly established reason to have genetic testing just for the PRL gene. Testing decisions are usually based on your symptoms, hormone levels, and family history, together with a doctor or genetic counselor.
A genetic result is only one part of your health story
A genetic test result can provide meaningful insight, but how much it can tell you varies by the condition and the type of variant involved. Lifestyle, environment, age, and medical history are among the many factors that shape how the body works over time. In some conditions, especially those influenced by many genes, genetic information offers context rather than certainty and is best understood along 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 context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how people respond to medicines. Some people break down a drug more slowly or more quickly, while others may be more or less sensitive to its effects. This is common and can help explain why the same treatment works well for one person, causes more side effects in another, or seems to have less effect in someone else.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes can affect the way they respond to medicines. By studying links between genes and medications, it helps explain why the same treatment may work differently in different people. For many drugs, genes influence how much effect a medicine has or how the body handles it. This information can support treatment choices that are more informed and more tailored to the individual. More detail on this topic is available in the LearnHub.
Drugs influenced by the PRL gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in predicting how medicines will work or which side effects may happen. Questions about symptoms, hormone concerns, or medication effects are best discussed with your doctor.
History
Research on the PRL gene grew out of much older work on prolactin, the hormone linked to milk production after childbirth. In the early 20th century, scientists identified a pituitary factor with lactation related effects, and later studies showed that this hormone was distinct from growth hormone. From these first observations, research expanded steadily. By the late 20th century, advances in genetics allowed researchers to identify and map the PRL gene, helping connect hormone production to its underlying inherited instructions. This work became part of a broader shift in endocrinology, where hormones once studied only by their effects could also be traced to specific genes. Over time, descriptions became more precise as molecular studies clarified how PRL is regulated in different tissues.