BTD rs397514355: Understanding Carrier Status
The rs397514355 variant is a genetic change located in the BTD gene, which is responsible for producing the enzyme biotinidase. This variant is identified as a carrier mutation associated with biotinidase deficiency, a condition that affects how the body recycles biotin.
What each genotype means
Typical biotinidase activity
This genotype represents the common, non-variant form of the BTD gene at this position. Individuals with this result do not carry this specific mutation associated with biotinidase deficiency.
This is the most common genotype observed in the general population.
Carrier of biotinidase deficiency
You carry one copy of the T allele, which is identified as a mutation associated with biotinidase deficiency. As a carrier, you typically have sufficient enzyme activity and do not exhibit symptoms of the condition, though you should discuss the implications of carrier status with a genetic counselor or clinician.
This genotype is rare in the general population.
Potential biotinidase deficiency
This genotype indicates the presence of two copies of the variant allele. You should consult with a healthcare provider or a metabolic specialist to discuss clinical testing for biotinidase activity, as this genotype may be associated with reduced enzyme function.
This genotype is extremely rare in the general population.
What is the rs397514355 Variant?
The rs397514355 variant is a specific single nucleotide polymorphism (SNP) found within the BTD gene. In genetics, a SNP represents a variation at a single position in the DNA sequence. This particular variant is categorized as a carrier mutation, meaning that individuals who carry one copy of this change typically do not exhibit the symptoms of the associated condition. The variant is located on chromosome 3 and is part of the genetic instructions that help the body process essential nutrients. Because it is classified as a rare variant, it is not commonly found in the general population, and its presence is usually identified through targeted genetic testing or clinical screening programs.
The Role of the BTD Gene
The BTD gene provides the essential instructions for the body to produce the enzyme biotinidase. This enzyme plays a critical role in recycling biotin, also known as vitamin H, which is a water-soluble B vitamin found in various foods like egg yolks, liver, and milk. Biotinidase works by releasing biotin from proteins in the diet, allowing the body to reuse this vitamin for various metabolic processes. Specifically, free biotin is required by enzymes called biotin-dependent carboxylases to break down fats, proteins, and carbohydrates. When the BTD gene contains mutations that reduce or eliminate the activity of this enzyme, the body struggles to recycle biotin effectively, which can lead to a condition known as biotinidase deficiency.
Research and Clinical Associations
Biotinidase deficiency is an inherited disorder that can manifest in two forms: profound and partial. Research indicates that this condition is inherited in an autosomal recessive manner, meaning an individual must typically inherit two copies of a pathogenic variant—one from each parent—to be affected by the disorder. Carriers, who possess only one copy of a pathogenic variant, generally remain asymptomatic. The evidence strength for rs397514355 as a carrier mutation is considered moderate, based on its identification in clinical settings. It is important to note that the presence of a single variant does not constitute a diagnosis of biotinidase deficiency. Clinical diagnosis is established through a combination of biochemical testing, such as measuring biotinidase enzyme activity in the blood, and molecular genetic testing to identify biallelic pathogenic variants.
Understanding Your Results
If you have received information regarding your status for rs397514355, it is essential to understand that this information is for educational purposes and does not replace professional medical advice. Being a carrier of a recessive condition is common, as most people carry several such variants without ever knowing. This information cannot be used to diagnose a health condition or predict specific medical outcomes. If you are concerned about your carrier status, particularly if you are planning a family, you should consult with a genetic counselor or a healthcare provider. They can help interpret your results in the context of your personal and family medical history and discuss the implications of carrier testing for you and your relatives.
How common is this variant?
The rs397514355 variant is considered rare in the general population according to data from the Genome Aggregation Database (gnomAD).
Frequently asked questions
What is biotinidase deficiency?
Biotinidase deficiency is a rare genetic disorder where the body cannot recycle biotin. If untreated, it can lead to symptoms like seizures, hair loss, and developmental delays, but it is manageable with lifelong biotin supplementation.
Does being a carrier mean I have the disease?
No, being a carrier of an autosomal recessive condition like biotinidase deficiency typically means you do not have the disease and do not show symptoms. Carriers have one normal copy of the gene and one variant copy.
How is biotinidase deficiency diagnosed?
Diagnosis is typically confirmed through newborn screening or blood tests that measure the activity level of the biotinidase enzyme. Molecular genetic testing is also used to identify pathogenic variants in the BTD gene.
Should I be worried about this variant?
Carrier status is a common finding and does not mean you are ill. However, if you are concerned about your genetic health or family planning, you should discuss these results with a qualified genetic counselor.
Sources & further reading
Educational information only, last refreshed 9/26/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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This variant is a known carrier mutation for biotinidase deficiency.
This variant is associated with carrier status for biotinidase deficiency.
Carrier variant associated with autosomal recessive biotinidase deficiency.
Carrier variant indicating predisposition to pass on autosomal recessive biotinidase deficiency.
Pathogenic missense variant causing biotinidase deficiency, a recessive metabolic disorder, making single-copy carriers important for reproductive genetic screening.