The CPLANE1 gene helps cells build and use tiny hairlike structures called cilia, which guide signals during early growth and development. This gene plays an important role in shaping the brain, face, and other organs before birth. If the gene does not work well, it can cause a ciliopathy such as Joubert syndrome, with low muscle tone, balance and coordination problems, developmental delay, and sometimes changes in breathing, the eyes, kidneys, or liver.
What is a gene?
A gene is a stretch of DNA that holds instructions your cells use to make molecules or guide processes in the body. Some genes provide the directions for producing proteins, the active parts of cells. Others mainly regulate when certain processes happen, where they occur, and how strongly they run. Together, genes affect how the body develops and works, and they can also shape how you respond to food, stress, or medications. For a deeper look at this topic, you can find more in the LearnHub.
Overview
CPLANE1Gene function
What if the gene works
The CPLANE1 gene helps cells build and use cilia, tiny hairlike structures that guide early body development and cell signaling. This supports normal growth of the brain, face, and other organs.
Risk
What if the gene does not work
Pathogenic variants in the CPLANE1 gene usually cause Joubert syndrome, affecting balance, coordination, eye movements, breathing control, and development. Milder or more severe variants can shift when features appear and whether extra findings, such as extra fingers or toes, are present.
Treatment
What does that mean for your treatment
At present, no CPLANE1-specific treatment or drug selection approach is established for people with a pathogenic variant in the CPLANE1 gene; care is symptom-based and tailored to the features each person has.
Conditions associated with CPLANE1
Gene function
What if the gene works
Many cells rely on tiny antenna-like structures called primary cilia to sense cues around them. The CPLANE1 gene helps cells build these structures and organize key helper proteins at their base. Understanding the CPLANE1 gene’s function helps explain how cells build primary cilia and respond to growth signals.
CPLANE1 helps cells assemble primary cilia, which act like small sensors on the cell surface. These cilia let cells pick up and pass along important messages from their surroundings.
This gene helps position cilia-building proteins at the base of the cilium. That organized setup allows the cilium to form in the right place and with the right parts.
Properly built cilia supported by CPLANE1 help cells receive growth and patterning signals. This supports coordinated body development and steady communication between cells.
What is a variant?
A genetic variant is a slight difference in the DNA sequence of a gene. These differences are common and help shape normal human diversity, including variation in appearance, metabolism, and the way the body responds to environmental influences. Many variants do not produce any noticeable effect and are simply part of natural genetic variation. At times, though, a variant can change how a gene works more clearly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
CPLANE1 gene variants can affect cilia formation by making the protein unstable, shortened, or less able to gather other proteins needed to build cilia in the right place. Milder changes, often some missense variants, may leave part of the protein working, while more severe truncating or splice variants can greatly reduce or abolish its activity. In people with Joubert syndrome related to the CPLANE1 gene, less residual function often goes with earlier or broader features.
How variants are linked to conditions
Pathogenic variants in the CPLANE1 gene cause Joubert syndrome, including forms historically grouped as oral-facial-digital syndrome type VI. In everyday terms, CPLANE1 gene variants linked to Joubert syndrome can be associated with low muscle tone, balance and coordination difficulties, unusual eye movements, and developmental delay, with some people also having extra fingers, tongue or mouth differences, or kidney, liver, or retinal involvement. Features vary widely from person to person.
A variant is not necessarily a diagnosis
Gene variants are a normal feature of human biology and are widely present in the general population. Most do not have a direct effect on health and instead 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 several genes and environmental factors also contribute. In some situations, though, a single well characterized variant in a particular gene is enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For CPLANE1, risk is mainly changed by inheritance: a child is at higher risk only if both parents carry a harmful changed copy of the gene, and this is more likely in families with a known history or when parents are blood relatives. There is not yet broadly confirmed evidence that lifestyle or everyday exposures change CPLANE1-related risk.
Inheritance of CPLANE1 variants
CPLANE1-related conditions are usually inherited in an autosomal recessive pattern. This means a child inherits one altered copy of the CPLANE1 gene from each parent, and the parents are typically healthy carriers. When both parents carry a variant in the CPLANE1 gene, each pregnancy has a 25% chance of being affected, a 50% chance of producing a carrier child, and a 25% chance of producing a child with two working copies. In practical terms, how CPLANE1 gene variants are inherited often becomes clear only after testing shows that both parents carry the same condition-linked gene change.
What does my CPLANE1 result mean for my family?
For CPLANE1, the main family pattern is recessive, which usually means parents are healthy carriers and brothers or sisters could also be affected or be carriers. A known CPLANE1 result can matter for close relatives, especially siblings and family members planning children, because carrier testing may clarify whether the same gene change runs in the family. The exact meaning depends on the specific result and the condition linked to it.
Genetic information
Genetic testing
How you find out about variants
To find out whether you carry a variant in the CPLANE1 gene, doctors use CPLANE1 genetic testing on a blood or saliva sample. A lab reads the gene's DNA sequence and compares it with the usual sequence to look for changes. Results may show a disease causing variant, a benign variant, or an unclear finding.
When should I consider getting a genetic test?
Consider testing for the CPLANE1 gene if a child has signs of Joubert syndrome or a related condition, such as low muscle tone, delayed development, unusual eye movements or breathing in infancy, extra fingers or toes, or a family history of these problems. Testing can also help explain the cause when a brain scan shows changes typical of these conditions.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but how much it explains varies depending on the condition and the type of variant involved. Many factors, including lifestyle, environment, age, and medical history, affect how the body functions over time. For some conditions, especially those influenced by many genes, genetic information provides context rather than certainty and is most helpful when considered alongside other parts of care. In other situations, a genetic result can offer a clear answer. In areas such as medication response, genetic results can help place 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 drug may work well for one person, seem less helpful for another, or cause more side effects in someone else. Differences in how the body absorbs, breaks down, and responds to a medication are common, and they can influence both treatment benefit and sensitivity.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in genes affect the way people respond to medicines. It studies patterns between genes and drugs to better understand 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 treatment decisions that are more informed and more individualized. More detail on this topic is available in the LearnHub.
Drugs influenced by the CPLANE1 gene
When should I seek medical advice?
There is no broadly confirmed role for this gene in guiding medication response, so questions about side effects, new symptoms, or how your medicines may be affecting you are best discussed with your doctor.
History
The CPLANE1 gene entered the medical literature under the earlier name C5orf42, when researchers were still mapping genes linked to rare inherited conditions. In the early 2010s, teams studying Joubert syndrome and related conditions identified variants in this gene in affected families. Over time, descriptions became more precise. As research clarified the gene’s role in cilia related pathways, its name was updated to CPLANE1 to better reflect that biology. This shift from a chromosome based placeholder name to a more informative gene name is a common step in genetics as evidence becomes clearer.