The protein made by the TBC1D23 gene helps cells move and recycle materials to the right place, which is especially important in the developing brain. If this gene does not work properly, that internal transport system can be disrupted, and some people may have developmental delay, intellectual disability, low muscle tone, seizures, or problems with coordination. Most people learn about the TBC1D23 gene through genetic testing in the setting of a rare inherited condition.
What is a gene?
A gene is a stretch of DNA that holds instructions your cells use to make molecules or regulate processes in the body. Some genes provide the directions for building proteins, the working parts of cells. Others mainly control when certain processes take place, where they occur, and how strongly they run. Together, genes affect how the body develops and functions, and they can influence how you respond to food, stress, and medications. For a deeper look at this topic, you can learn more in the LearnHub.
Overview
TBC1D23Gene function
What if the gene works
The TBC1D23 gene helps sort and move proteins inside cells, including to the cell’s shipping center. This supports normal cell organization and is important for healthy brain development and nerve cell function.
Risk
What if the gene does not work
More disruptive variants in the TBC1D23 gene can cause a neurodevelopmental condition, often with developmental delay, intellectual disability, and poor balance or low muscle tone. Milder variants may lead to later onset and less marked features.
Treatment
What does that mean for your treatment
No treatment or drug selection approach specific to a pathogenic variant in the TBC1D23 gene is currently established, so care is guided by symptoms and daily needs.
Gene function
What if the gene works
Inside your cells, careful package delivery keeps proteins and membranes in the right place. The TBC1D23 gene supports this internal shipping system by helping transport carriers reach the Golgi, a cell sorting center. Understanding how the TBC1D23 gene helps cells move proteins makes its day to day role easier to picture.
The TBC1D23 gene helps shuttle transport carriers inside cells. It supports movement from endosomes (cell recycling compartments) to the Golgi, a sorting center that directs proteins to their next destination.
Its protein helps incoming carriers latch onto the Golgi at the right spot. It works as a connector between the carrier and Golgi holding proteins, so cargo can be handed over in an orderly way.
By supporting these deliveries, the TBC1D23 gene helps keep proteins and membranes on the proper cellular route. This steady traffic supports normal cell organization and routine day to day activity.
What is a variant?
A genetic variant is a small difference in the DNA sequence within a gene. These differences are common and are part of normal human diversity, including differences in appearance, metabolism, or how the body responds to environmental influences. Many variants do not have any noticeable effect and simply represent natural genetic variation. In some situations, though, a variant can change how a gene functions more substantially and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the TBC1D23 gene can disrupt how cells sort and move cargo, especially in the pathway that sends materials from endosomes back to the Golgi. Many TBC1D23 gene variants reduce the amount of working protein, while others may alter its shape and weaken its ability to link transport vesicles to partner proteins. Milder variants may leave some activity intact, but more severe loss of function variants can lead to a larger breakdown in cellular trafficking and, in some cases, earlier or more marked developmental effects.
How variants are linked to conditions
Pathogenic variants affecting both copies of the TBC1D23 gene cause a rare inherited condition called pontocerebellar hypoplasia type 11. In medical genetics, TBC1D23 gene variants and developmental delay are most clearly linked through this diagnosis, which often includes delayed speech and movement skills, learning difficulties, and reduced growth of parts of the brain seen on scans. Some people also have hearing loss or seizures.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are common across 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 role. 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?
There isn't yet broadly confirmed evidence on specific factors that increase or reduce health risk related to the TBC1D23 gene. People with concerns about their personal or family risk can discuss it with a doctor or genetic counselor.
Inheritance of TBC1D23 variants
Known TBC1D23-related conditions follow an autosomal recessive inheritance pattern. This means a child inherits one TBC1D23 variant from each parent, while parents who carry one variant usually do not have the condition themselves. When both parents carry a variant in the TBC1D23 gene, each pregnancy has a 25% chance of being affected, a 50% chance of producing a child who is a carrier, and a 25% chance of producing a child with neither variant. This autosomal recessive TBC1D23 inheritance pattern affects sons and daughters equally.
What does my TBC1D23 result mean for my family?
For families with a disease-causing change in the TBC1D23 gene, the pattern is usually recessive, which means close relatives may also be carriers even if they do not have symptoms. Brothers and sisters could also be affected or carry the same gene change. This can matter for future pregnancies and for relatives who are planning children.
Genetic information
Genetic testing
How you find out about variants
To find out about TBC1D23 variants, TBC1D23 genetic testing reads the DNA sequence of the TBC1D23 gene from a blood sample, saliva, or cheek swab. This can be done as part of a multigene panel, exome sequencing, or a test focused on this gene. Results may identify a pathogenic variant, a benign variant, or a variant of uncertain significance.
When should I consider getting a genetic test?
Testing for the TBC1D23 gene may be considered when a child has unexplained developmental delay, learning problems, seizures, or certain brain scan changes, especially if similar features run in the family. It can also help clarify the cause when more than one child in a family is affected.
A genetic result is only one part of your health story
A genetic result can provide useful insight, but what it can tell you depends on the condition and on 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 shaped by many genes, genetic information offers context rather than certainty and is best considered alongside other parts of care. In other situations, a genetic result may give a clear answer. In areas like medication response, genetic results can help put individual experiences into perspective.
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 than others, so the same treatment may work better, work less well, or cause more side effects. This kind of difference is common and is one reason medication response can vary from person to person.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect the way people respond to medications. It looks at connections between genes and drugs 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 and individualized treatment decisions. To explore this topic in greater detail, you can learn more in the LearnHub.
Drugs influenced by the TBC1D23 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medication response, so questions about medicines, side effects, or changes in your health are best discussed with your doctor.