The SLC35C1 gene helps move a sugar called fucose inside cells so it can be attached to many proteins. If this gene does not work properly, cells may struggle to communicate and function as they should, especially in the immune system. People with pathogenic variants in both copies of the SLC35C1 gene can have recurrent infections, slow growth, developmental delay, and sometimes a rare blood type pattern called the Bombay phenotype. This is a rare gene and is not widely known in popular culture.
What is a gene?
Genes are pieces of DNA that give cells instructions for making molecules or for regulating processes in the body. Some carry the directions to produce proteins, which are the parts of cells that do the work. Others are used mainly to guide when certain processes happen, where they happen, and how active they are. As a group, genes affect how the body grows and works, and they can influence your response to food, stress, and medicines. For more detail, visit the LearnHub.
Overview
SLC35C1Gene function
What if the gene works
The SLC35C1 gene helps move fucose, a sugar building block, into the part of the cell that finishes proteins. This supports cell communication, immune cell movement, and normal growth.
Risk
What if the gene does not work
Variants in the SLC35C1 gene can cause a rare condition with frequent infections, growth delay, and developmental delay. Milder and more severe variants may influence when features appear and how pronounced they are.
Treatment
What does that mean for your treatment
Pathogenic variants in the SLC35C1 gene can make oral L-fucose treatment relevant, because some people show fewer infections and lower white blood cell counts with it. Response varies by variant, and changes that leave some transporter activity may respond better than variants with no remaining activity. Care also includes standard supportive treatment for symptoms.
Conditions associated with SLC35C1
Gene function
What if the gene works
In daily cell work, the SLC35C1 gene helps move a sugar building block called GDP fucose to the place where cells finish many proteins and fats. This is a central part of SLC35C1 gene function. When this process runs normally, cells can place fucose sugar tags where they are needed for routine cell activity.
The SLC35C1 gene helps carry GDP fucose into the Golgi, a cell compartment that finishes many molecules. This gives cells access to the fucose they need for later steps.
Cells use the delivered fucose to add small sugar tags to proteins and fats. These finishing touches help shape how cell surface molecules are built and displayed.
Fucose containing sugar tags help cells interact with other cells in an organized way. They support normal cell signaling, cell attachment, and everyday communication between tissues.
What is a variant?
Within a gene, a genetic variant is a small change in the DNA sequence. These changes are common and help account for normal human diversity, including differences in appearance, metabolism, and how the body responds to environmental influences. Many variants have no noticeable effect and are simply part of natural genetic variation. Sometimes, though, a variant changes 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 SLC35C1 gene often change the shape or stability of its transporter protein, so less of a sugar called fucose reaches the Golgi (the cell's packaging center) for sugar tagging of proteins. This is how SLC35C1 gene variants affect glycosylation (the cell's sugar tagging process). Milder variants may leave some transport activity, while more severe variants can nearly eliminate it. In SLC35C1-CDG, that difference can influence how early and how strongly features appear.
How variants are linked to conditions
Disease-causing variants in the SLC35C1 gene cause leukocyte adhesion deficiency type 2, also called congenital disorder of glycosylation type IIc. This rare inherited condition is linked to recurrent infections, slow growth, developmental delay, and a persistently high white blood cell count. Across medical genetics studies, the SLC35C1 gene and leukocyte adhesion deficiency type 2 are a well-established genetic pairing, and finding disease-causing variants in both copies of the gene confirms 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 human diversity. 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 are part of the picture. In other situations, though, one well-characterized variant in a particular gene may be enough to confirm a diagnosis.
Are there things that can increase or change my risk?
For SLC35C1, risk is mainly set by inheritance: a child is affected only if they inherit a changed copy from both parents. There is not broadly confirmed evidence that lifestyle or everyday exposures meaningfully increase or lower the chance of this condition. Family history and whether both parents carry a variant are the key factors.
Inheritance of SLC35C1 variants
SLC35C1-related conditions are inherited in an autosomal recessive pattern. This means a child usually needs to inherit one changed copy of the SLC35C1 gene from each parent to be affected. In families asking about the SLC35C1 inheritance pattern, two carrier parents have a 25% chance with each pregnancy to have an affected child, a 50% chance to have a carrier child, and a 25% chance to have a child without the familial variant. Parents who carry one variant are typically not affected.
What does my SLC35C1 result mean for my family?
For families with an SLC35C1-related condition, the pattern is usually recessive, which means parents are often healthy carriers. Brothers and sisters may also have the condition or be carriers, and other relatives on both sides of the family may carry the same gene change. Because of that, a known SLC35C1 result can matter for family planning and for relatives who want to understand their own chance of being carriers.
Genetic information
Genetic testing
How you find out about variants
Genetic testing for SLC35C1 variants usually uses a blood or saliva sample to read the DNA sequence, often through a single-gene test, a broader gene panel, or exome sequencing. Finding two pathogenic variants in the SLC35C1 gene, usually one inherited from each parent, can confirm an SLC35C1-related condition.
When should I consider getting a genetic test?
Testing for changes in the SLC35C1 gene may be considered when a child has repeated serious infections, poor growth, developmental delay, and test results suggesting a rare inherited condition that affects how cells handle sugars. It can also be useful when there is a family history of this condition or both parents are known carriers.
A genetic result is only one part of your health story
A genetic result can be informative, but how much it can tell you varies based on the condition and the kind of variant involved. Over time, many factors, including lifestyle, environment, age, and medical history, also influence how the body functions. For some conditions, especially those shaped by many genes, genetic information provides context rather than certainty and is best interpreted alongside other parts of care. In other situations, a genetic result can give a clear answer. In areas like medication response, genetic results can also help put a person’s experiences into context.
Pharmacogenetics
How variants shape your response to medicine
Genetic variation can affect how your body handles certain medicines, so the same treatment may not work the same way for everyone. These inherited differences can change how quickly a drug is broken down, how much of it reaches its target, or how strongly your body responds to it. As a result, some people get the expected benefit, while others may find that a medicine works less well or causes more side effects.
What is Pharmacogenetics?
Pharmacogenetics examines how differences in genes can affect the way someone responds to medication. It studies 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 understanding can support more informed and more individualized treatment decisions. More information on this topic is available in the LearnHub.
Drugs influenced by the SLC35C1 gene
When should I seek medical advice?
There is not yet a broadly confirmed role for this gene in guiding medicine choice or predicting drug side effects, so general concerns about symptoms, treatment, or medicines are best discussed with your doctor or pharmacist.