PAH rs76687508: Understanding Carrier Status for Phenylketonuria
The rs76687508 variant is a specific change located within the PAH gene. It is recognized in genetic databases as a marker associated with carrier status for phenylketonuria (PKU), an inherited metabolic disorder.
What each genotype means
Typical genetic profile
This genotype represents the most common form of the PAH gene at this specific location. Individuals with this profile do not carry this specific variant associated with phenylketonuria.
This is the most common genotype observed in the general population.
Phenylketonuria carrier status
This genotype indicates you are a carrier of a variant associated with phenylketonuria. Carriers are typically unaffected by the condition, as it generally requires inheriting a second variant from the other parent to manifest symptoms.
This genotype is rare in the general population.
Potential phenylketonuria risk
This genotype indicates the presence of two copies of the variant associated with phenylketonuria. You should consult with a medical professional or genetic counselor to discuss the clinical implications and potential for metabolic health impacts.
This genotype is extremely rare in the general population.
What is the rs76687508 Variant?
The rs76687508 variant is a single nucleotide polymorphism (SNP) found on chromosome 12. In the context of human genetics, a SNP represents a variation at a single position in the DNA sequence. This specific variant is situated within the PAH gene, which provides instructions for creating the phenylalanine hydroxylase enzyme. Geneticists track these variants to understand how specific changes in the DNA code might influence biological processes or disease risk. Because rs76687508 is located in a gene critical for metabolism, it has been studied for its potential impact on how the body processes certain amino acids. It is important to note that the presence of a variant does not automatically imply a health condition, but rather serves as a point of interest for researchers studying the genetic architecture of metabolic traits.
The Role of the PAH Gene
The PAH gene is responsible for producing the enzyme phenylalanine hydroxylase. This enzyme is essential for the body to break down phenylalanine, an amino acid found in many protein-rich foods and artificial sweeteners. When the PAH gene functions correctly, it converts phenylalanine into tyrosine, another amino acid that the body uses for various important functions. If the PAH gene contains variants that significantly reduce or eliminate the activity of this enzyme, phenylalanine can build up to toxic levels in the blood and brain. This accumulation is the underlying cause of phenylketonuria (PKU). Because PKU is an autosomal recessive condition, an individual typically needs to inherit two non-functional copies of the gene—one from each parent—to experience the symptoms of the disorder. Understanding the function of the PAH gene is key to grasping why certain variants are categorized as potential carriers.
Research and Evidence Strength
The association between rs76687508 and phenylketonuria is classified as having moderate evidence. Research into this variant often involves analyzing its presence in individuals who have been diagnosed with PKU or those who are known carriers. While some variants in the PAH gene are well-documented as pathogenic, the clinical significance of any single variant can vary based on the specific population studied and the availability of functional data. Current scientific literature, including data aggregated in resources like ClinVar and SNPedia, identifies this variant as a marker for carrier status. However, genetic interpretation is a complex field, and the impact of a single SNP can be influenced by other genetic factors. Researchers continue to study how such variants affect enzyme activity levels, which helps clinicians better understand the spectrum of phenylalanine metabolism disorders.
Population Frequency
The rs76687508 variant is considered rare in the general population. Population databases like gnomAD provide insights into how frequently specific alleles appear across different ancestral groups. Because this variant is linked to a recessive condition, it is expected to be found at low frequencies in the general population, as most individuals do not carry two copies of a pathogenic variant. The distribution of such variants can vary significantly between different ethnic and geographic groups due to historical population patterns. When a variant is rare, it means that the vast majority of people do not carry it. Geneticists use these frequency data to help determine the likelihood that a variant is benign or potentially harmful, as variants that cause severe disease are often kept at very low frequencies by natural selection.
Interpreting Your Genetic Information
If you have received information about your status for rs76687508, it is important to understand what this means in a practical sense. Being a carrier for a recessive condition like PKU generally means that you have one copy of a variant that could potentially affect PAH enzyme function, but you likely do not have the disorder yourself. This information is primarily relevant for family planning and understanding your genetic background. It is not a medical diagnosis, and it cannot predict your health outcomes on its own. If you are concerned about your carrier status or have a family history of metabolic disorders, the most appropriate step is to consult with a genetic counselor or a healthcare professional. They can provide context based on your full medical history and help you understand the implications of your genetic results in a way that is accurate and personalized.
How common is this variant?
The rs76687508 variant is rare in the general population, with most individuals carrying the common C allele.
Frequently asked questions
What does it mean to be a carrier for PKU?
Being a carrier means you have one copy of a gene variant associated with PKU, but you do not have the condition yourself. Because PKU is recessive, you would generally need to inherit a second variant from your other parent to be at risk for the disorder.
Is rs76687508 a diagnosis for phenylketonuria?
No, this variant is not a diagnosis. It is a genetic marker associated with carrier status, and genetic testing results should always be discussed with a qualified healthcare provider to understand their clinical relevance.
Should I change my diet if I am a carrier?
There is no evidence that being a carrier for a PKU variant requires dietary changes. If you have concerns about your metabolic health or diet, please consult with a doctor or a registered dietitian.
How can I find out if my partner is also a carrier?
If you are concerned about the risk of passing a condition to children, you can speak with a genetic counselor. They can explain the options for carrier screening for your partner and discuss the inheritance patterns of recessive conditions.
Sources & further reading
Educational information only, last refreshed 9/30/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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This variant is identified as a carrier marker for phenylketonuria mutations.
This variant is associated with carrier status for phenylketonuria, a metabolic disorder.
This variant is considered probably pathogenic and is associated with phenylketonuria carrier status.
This variant is associated with carrier status for phenylketonuria, a metabolic disorder.
A missense variant (c.1222C>T, p.Arg408Trp) that disrupts phenylalanine hydroxylase activity, defining carrier status for classic autosomal recessive phenylketonuria across Eastern and Northern Europe.
A splice-donor site variant (c.1066-11G>A, legacy IVS10nt-11) causing phenylalanine hydroxylase deficiency and serving as a frequent carrier screening marker for phenylketonuria.