The TMEM165 gene helps a cell’s packaging center add sugar chains to proteins correctly, a step many tissues need to work normally. If this gene does not work well, that process can break down and cause a rare inherited condition called TMEM165-CDG. People with this condition may have developmental delay, slow growth, low muscle tone, and changes affecting the bones, liver, or other organs.
What is a gene?
Genes are stretches of DNA that hold instructions your cells use to make molecules or regulate processes in the body. Some genes carry the instructions for producing proteins, the parts of cells that do the work. Other genes mostly help direct when certain processes happen, where they happen, and how strongly they operate. In combination, genes affect how the body develops and works, and they can also shape how you respond to food, stress, or medications. To explore this topic in more depth, you can find more in LearnHub.
Overview
TMEM165Gene function
What if the gene works
Your cells use the TMEM165 gene to help the Golgi, a cell compartment, add sugar tags to proteins correctly. This supports normal growth and the healthy function of many tissues.
Risk
What if the gene does not work
Variants in the TMEM165 gene can cause a congenital glycosylation condition with growth delay, developmental delay, low muscle tone, and bone changes. Effects can range from milder to more severe, with variable timing and features.
Treatment
What does that mean for your treatment
No treatment or management approach specific to pathogenic or loss-of-function variants in the TMEM165 gene is currently established in clinical guidelines. Small studies have explored galactose or manganese-based approaches to improve glycosylation in TMEM165-related disease, but these remain investigational rather than standard care.
Conditions associated with TMEM165
Gene function
What if the gene works
Many of your cells need a steady, well-balanced Golgi apparatus to finish proteins and fats before they are sent where they are needed. In your body, the TMEM165 gene supports processes that help these molecules receive the right sugar markings. This careful finishing step helps tissues work smoothly from day to day.
The TMEM165 gene helps control the balance of manganese, calcium, and acidity inside the Golgi apparatus. This balanced setting lets the Golgi carry out its routine finishing work in a steady way.
One of its main jobs is to support glycosylation (the process of adding sugar chains to proteins and fats). These sugar chains help many molecules fold properly, stay stable, and reach the right place.
By keeping the Golgi environment suitable, this gene supports the final processing and sorting of many cell products. That means proteins and fats can leave the Golgi in a form your body can use.
What is a variant?
A genetic variant is a small difference in the DNA sequence of a gene. These differences are common and are part of normal human diversity, including variation in appearance, metabolism, and 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 significantly and may contribute to or cause a genetic condition.
Genetic variants
What if the gene does not work
Variants in the TMEM165 gene can make the protein unstable, misfolded, or unable to stay in the Golgi, a cell compartment that processes proteins. This is how variants influence the TMEM165 gene's function, often disturbing manganese balance and glycosylation (the sugar tagging used to finish many proteins). Milder missense variants may leave activity, while more disruptive variants can cause little or no working protein. In TMEM165-related congenital disorders of glycosylation, this can influence early symptoms and how pronounced they are.
How variants are linked to conditions
Having pathogenic variants in both copies of the TMEM165 gene causes TMEM165-CDG, a rare inherited condition. People with this condition linked to the TMEM165 gene may have growth and developmental delays, low muscle tone, bone changes, and liver involvement. Symptoms and severity can vary from person to person.
A variant is not necessarily a diagnosis
Genetic variants are a routine part of human biology and are widely seen 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 suggests a possible link rather than a certain diagnosis, especially when several genes and environmental factors also contribute. In some situations, though, a single well-characterized variant in a specific gene is enough to establish a diagnosis.
Are there things that can increase or change my risk?
For TMEM165, risk is mainly shaped by inherited gene changes rather than lifestyle or everyday exposures. A child’s chance of having a TMEM165-related condition is higher when both biological parents carry a nonworking TMEM165 copy, and it can also be higher in families where the parents are related by blood, such as cousins.
Inheritance of TMEM165 variants
TMEM165-related health conditions are inherited in an autosomal recessive pattern. This means a child usually inherits one TMEM165 gene variant from each parent, and both parents are often healthy carriers. When both parents carry a variant, each pregnancy has a 25% chance of being affected, a 50% chance of resulting in a carrier child, and a 25% chance of inheriting no familial variant. This is the usual answer to how TMEM165 variants are inherited in families.
What does my TMEM165 result mean for my family?
For families, a TMEM165-related condition is usually passed down in a recessive way, so parents of an affected child are often healthy carriers. Brothers and sisters may also be affected or may be carriers, and close relatives could carry the same changed gene without knowing it. This can matter for future pregnancies and for relatives who are planning children.
Genetic information
Genetic testing
How you find out about variants
TMEM165 genetic testing looks for variants in the TMEM165 gene using a blood sample, saliva sample, or sometimes cheek cells. A lab reads the DNA code and compares it with the usual sequence to see whether a variant is present. Results can help clarify whether TMEM165-related findings have a genetic cause.
When should I consider getting a genetic test?
Genetic testing for the TMEM165 gene may be considered when a child has unexplained developmental delay, poor growth, bone or joint changes, or other signs of a rare inherited condition that affects how the body builds and processes sugars. It can help when there is a family history of this condition or a TMEM165 variant in the family.
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 the specific type of variant involved. How the body works over time is shaped by many factors, including lifestyle, environment, age, and medical history. For some conditions, especially those affected 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 such as 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. A treatment that works well for one person may work less well for another, or may cause more side effects, because the body can absorb, break down, transport, or respond to drugs differently. These differences are common and can influence how strongly a medicine works or how sensitive someone is to it.
What is Pharmacogenetics?
Pharmacogenetics examines how genetic differences affect the way people respond to medications. It focuses on the relationship between genes and drugs to help explain why the same treatment may work differently from one person to another. For many medicines, genes can influence how strongly a drug works or how the body handles it. This information can support treatment decisions that are more informed and more personalized. To explore this topic in greater detail, you can learn more in the LearnHub.
Drugs influenced by the TMEM165 gene
When should I seek medical advice?
There is not yet a well-confirmed role for this gene in showing how medicines will work or what side effects may happen. Questions about treatment, side effects, or new symptoms are best discussed with your doctor.
History
The TMEM165 gene entered medical genetics relatively recently, after being identified through broader efforts to map and name previously unknown human genes. In recent decades, awareness of this gene’s role has grown as researchers linked variants in TMEM165 to a rare inherited condition affecting body chemistry. Early reports focused on children with shared clinical features, and later studies connected those findings to changes in this specific gene. As medical science evolved, so did understanding of this gene. Over time, descriptions became more precise, especially as laboratory methods improved and more families were identified worldwide. Today, TMEM165 is recognized mainly through this modern genetic work rather than through a long public or cultural history.