The FAM111A gene gives cells instructions for a protein that helps them copy DNA and grow in an organized way. This gene plays an important role in bone development and in glands that help control calcium levels. When a harmful variant disrupts it, a person may have short stature, bone and skull changes, and low calcium linked to underactive parathyroid glands. Variants in the FAM111A gene are linked to Kenny-Caffey syndrome type 2, and more disruptive variants can cause osteocraniostenosis.
What is a gene?
A gene is a stretch of DNA that holds information your cells use to make molecules or regulate processes in the body. Some genes carry the instructions for producing proteins, which are the working parts of cells. Other genes mainly help control when certain processes happen, where they take place, and how strongly they run. Together, genes influence how the body develops and functions, and they can shape how you respond to food, stress, or medications. If you want to explore this topic more deeply, you can find more in the LearnHub.
Overview
FAM111AGene function
What if the gene works
The FAM111A gene helps make a protein involved in copying DNA as cells divide. This supports normal growth and development, especially in tissues that need steady cell renewal.
Risk
What if the gene does not work
Variants in the FAM111A gene can cause a spectrum from Kenny-Caffey syndrome type 2 to the more severe osteocraniostenosis. People may have poor bone growth, short stature, low calcium, and in severe cases very small, fragile bones.
Treatment
What does that mean for your treatment
No FAM111A-specific treatment or drug selection approach is currently established. Care is guided by the person’s symptoms and complications rather than the FAM111A gene itself. FAM111A is mainly being studied in early-stage research on cell growth and some cancers, not yet to guide routine treatment.
Conditions associated with FAM111A
Gene function
What if the gene works
As cells prepare to divide, they need a steady way to copy DNA. Your cells rely on the FAM111A gene to support that work in the nucleus, where DNA is stored. This protein mainly supports DNA copying and the orderly steps that lead into normal cell division.
FAM111A gathers at sites where DNA is being copied before a cell divides. There, it supports smooth progress as new DNA strands are built.
The FAM111A protein acts as a protease (a protein-cutting enzyme). This lets it trim certain proteins at DNA copying sites, which can help clear obstacles from the path of the copying machinery.
By supporting DNA replication, FAM111A helps cells move through the growth and division cycle in an orderly way. This is especially important in tissues that regularly renew themselves.
What is a variant?
A genetic variant is a minor difference in the DNA sequence within a gene. These differences are common and help shape normal human diversity, including variation in appearance, metabolism, and the way the body reacts to environmental influences. Many variants do not cause any noticeable effect and are simply part of natural genetic variation. At times, though, a variant can change how a gene works more significantly and may contribute to or lead to a genetic condition.
Genetic variants
What if the gene does not work
Many FAM111A gene variants alter a protein-cutting enzyme so it becomes too active or harder for cells to control. Studies on how FAM111A gene variants affect protein function suggest that some changes increase self-cutting and disrupt other proteins inside the cell. Milder variants may cause a smaller effect, while more severe variants can create a stronger harmful effect. This often lines up with the milder Kenny-Caffey syndrome type 2 pattern or the earlier, more marked osteocraniostenosis pattern.
How variants are linked to conditions
Pathogenic variants in the FAM111A gene cause Kenny-Caffey syndrome type 2 and can also lead to osteocraniostenosis, a more severe condition affecting bone growth and skull development. These FAM111A gene variants are linked to a spectrum of findings that may include short stature, dense or thickened bones, low calcium levels, and eye problems such as cataracts. In this setting, finding a disease-causing FAM111A variant can confirm the diagnosis.
A variant is not necessarily a diagnosis
Genetic variants are common across the general population and are a normal feature of human biology. Most do not directly affect health and simply contribute to natural differences between people. For many genes, having a variant associated with a condition points to a possible link rather than a certain diagnosis, particularly when several genes and environmental influences play a role. Still, in some situations, 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 is not yet broadly confirmed evidence on specific factors that increase or reduce health risk related to the FAM111A gene. For many living with a disease-causing FAM111A change, the main factor is the genetic variant itself, while care usually centers on watching for complications and treating symptoms early.
Inheritance of FAM111A variants
FAM111A-related conditions are inherited in an autosomal dominant pattern, which means a variant in one copy of the FAM111A gene can be enough to cause disease. If a parent carries a disease-causing FAM111A variant, each child has a 50% chance of inheriting it. The FAM111A inheritance pattern also includes new, de novo variants, so some affected children are the first person in the family to have the condition. In practical terms, a variant can be passed from a mother or father to a son or daughter.
What does my FAM111A result mean for my family?
For FAM111A, family impact is usually discussed as a dominant pattern, which means a parent, sibling, or child may also carry the same gene change. Close relatives may want to talk with their care team about whether the finding could apply to them as well. Some FAM111A changes happen new in a child, so a parent is not always the source.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the FAM111A gene, doctors use genetic testing for FAM111A variants with a blood or saliva sample. A lab reads the gene's DNA sequence to look for changes linked to Kenny-Caffey syndrome type 2 or osteocraniostenosis. Results may show a pathogenic variant, no relevant variant, or an uncertain result.
When should I consider getting a genetic test?
Genetic testing for the FAM111A gene may be worth considering if a child has signs such as short stature, unusually thin or fragile bones, low calcium from underactive parathyroid glands, or delayed closing of the soft spots in the skull. It can also help when these findings run in the family or doctors suspect Kenny-Caffey syndrome type 2 or osteocraniostenosis.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but how much it reveals depends on the condition and on the kind of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, also influence how the body functions. In some conditions, particularly those shaped by many genes, genetic information offers context rather than certainty and is best considered 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 personal experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body responds to medicines. Small differences in genes can change how a drug is broken down, moved through the body, or how strongly it acts on its target, so the same treatment may work better for some people than for others. This is a common reason people can differ in how much benefit they get from a medicine or how sensitive they are to side effects.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in a person’s genes can affect their response to medications. It looks at gene and drug patterns to help explain why the same treatment may work differently from one person to another. For many medicines, genes influence how strongly a drug works or how the body handles it. This information can support more informed, more individualized treatment decisions. More detail on this topic is available in the LearnHub.
Drugs influenced by the FAM111A gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication response. If you have questions about side effects, medicine changes, or how a treatment is affecting you, talk with your doctor or pharmacist.
History
FAM111A entered medical genetics through studies of rare inherited conditions affecting bone growth and calcium balance. Initially understood only through visible traits, later recognized as tied to a specific gene, it became especially important when researchers connected variants in the FAM111A gene to Kenny-Caffey syndrome and osteocraniostenosis in the 2010s. Those findings helped show that conditions once described mainly by their outward features could be linked to one shared genetic cause. From these first observations, research expanded steadily, and doctors began to see that different FAM111A variants could lead to a range of findings. This history reflects a broader shift in genetics, from describing syndromes by appearance to identifying their molecular basis.