PAH rs75193786: Understanding This Genetic Variant
The rs75193786 variant is located within the PAH gene, which provides instructions for making the enzyme phenylalanine hydroxylase. This variant has been studied for its potential association with phenylketonuria (PKU), a condition that affects how the body processes the amino acid phenylalanine.
What each genotype means
Typical enzyme activity
You do not carry the pathogenic T allele for this specific PAH variant. Having two typical reference alleles means this variant does not contribute to a reduced phenylalanine hydroxylase enzyme activity or carrier status for phenylketonuria. This result does not exclude the possibility of carrying variants elsewhere in the PAH gene.
Carried by more than 99.9% of individuals across global populations.
PKU carrier status
You carry one copy of the pathogenic variant in the PAH gene associated with autosomal recessive phenylketonuria. Carriers typically produce sufficient functional phenylalanine hydroxylase enzyme and generally do not develop hyperphenylalaninemia or clinical symptoms of PKU. However, carrier status is relevant for reproductive planning, as having a child with another carrier creates a 25% risk of phenylketonuria in each pregnancy.
Carried by approximately 1 in 1,100 individuals globally (gnomAD MAF ~0.00045).
Likely PKU risk genotype
Individuals with two copies of this variant carry homozygous alterations in the PAH gene, which are associated with significant phenylalanine hydroxylase deficiency and phenylketonuria (PKU). Research indicates that clinical severity and dietary responsiveness can vary depending on total residual enzyme activity. Anyone with this genotype should review their metabolic and clinical profile with a genetic counselor or metabolic disease specialist.
Extremely rare globally, estimated at less than 1 in 1,000,000 individuals.
What is rs75193786?
The rs75193786 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 is responsible for encoding the phenylalanine hydroxylase enzyme. Researchers track these variants to understand how small changes in the genetic code might influence biological functions or disease susceptibility. Because this variant is located in a gene known to be involved in metabolic processes, it has been the subject of investigation in clinical genetics databases. It is important to note that the presence of a variant does not automatically imply a health condition, as many genetic variations are benign or have limited clinical impact. Scientists use large-scale genomic datasets to determine if specific variants occur more frequently in individuals with certain health traits compared to the general population.
The Role of the PAH Gene
The PAH gene is essential for the production of the enzyme phenylalanine hydroxylase. This enzyme is primarily active in the liver and is responsible for converting the amino acid phenylalanine into another amino acid called tyrosine. Phenylalanine is a building block of proteins obtained through the diet. When the PAH gene functions correctly, the body maintains appropriate levels of phenylalanine. However, if the PAH gene contains variants that significantly reduce or eliminate the activity of this enzyme, phenylalanine can accumulate to toxic levels in the blood and tissues. The brain is particularly sensitive to high concentrations of phenylalanine, which is why proper regulation of this amino acid is critical for neurological health. Variants in the PAH gene are the primary cause of phenylketonuria (PKU), a metabolic disorder that, if left untreated, can lead to intellectual disability and other serious health complications.
Research and Clinical Evidence
Research into rs75193786 is ongoing, and the current evidence regarding its clinical impact is considered limited. While some databases and literature have associated this variant with phenylketonuria, the classification of such variants can be complex. In clinical genetics, a variant may be labeled as a 'variant of uncertain significance' (VUS) when there is not enough evidence to definitively categorize it as pathogenic or benign. Different studies may report varying findings based on the populations they analyze or the methods used to assess the variant's effect on protein function. Because the PAH gene is highly polymorphic, meaning it has many different variants, researchers must carefully distinguish between those that cause disease and those that are harmless. Consumers should be aware that genetic associations are often statistical in nature and do not replace professional clinical evaluation. Always consult with a healthcare provider or a genetic counselor to interpret how specific genetic findings relate to your personal health.
Population Frequency
The rs75193786 variant is relatively rare in the general population. According to data from the Genome Aggregation Database (gnomAD), the minor allele frequency (MAF) is approximately 0.00045 across global populations. This low frequency indicates that the variant is not commonly found in the general public. Because it is rare, it is difficult for researchers to gather large amounts of data to confirm its exact clinical significance. Genetic frequency can also vary significantly between different ancestral groups due to historical population patterns, such as founder effects or genetic drift. Understanding these frequencies helps scientists prioritize which variants to study further, but it also highlights the importance of considering individual genetic context when evaluating the potential impact of any specific SNP.
What You Can Do With This Information
If you have received information about your status for rs75193786, it is important to approach it with perspective. Genetic testing results are not a medical diagnosis. If you are concerned about your risk for phenylketonuria or other metabolic conditions, the most appropriate step is to speak with a qualified healthcare professional, such as a medical geneticist or a genetic counselor. They can help you understand the limitations of the test, the strength of the evidence for this specific variant, and whether further clinical testing is necessary. Do not make any changes to your diet or medical regimen based on a single genetic variant report without professional guidance. Genetic information is just one piece of the puzzle; your overall health is determined by a combination of your genetics, environment, and lifestyle. A clinician can provide the necessary context to help you make informed decisions about your health.
How common is this variant?
The rs75193786 variant is rare, with a minor allele frequency of approximately 0.00045 across global populations according to gnomAD.
Frequently asked questions
Is rs75193786 a diagnosis for PKU?
No, rs75193786 is not a diagnosis. Genetic variants are only one factor in determining health, and a clinical diagnosis of PKU requires specialized blood testing and evaluation by a medical professional.
What should I do if I have the C/C genotype?
If you have this genotype, you should consult with a genetic counselor or a physician. They can help you understand what this means for your health and whether any follow-up clinical testing is appropriate.
Why is the evidence for this variant limited?
The evidence is limited because the variant is rare, making it difficult for researchers to conduct large-scale studies. Additionally, many variants in the PAH gene require extensive functional testing to confirm their impact on enzyme activity.
Can I change my diet based on this result?
You should not change your diet based on a genetic report. Dietary changes for metabolic conditions must be managed by a healthcare provider to ensure nutritional needs are met safely.
Sources & further reading
Educational information only, last refreshed 10/11/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Pathogenic missense variant (p.Arg408Trp) associated with phenylketonuria (PKU).
A severe pathogenic missense variant (p.Arg408Trp) in the PAH gene associated with phenylketonuria.
Missense variant (c.1222C>T, p.Arg408Trp) that disrupts phenylalanine hydroxylase activity, associated with phenylketonuria.
Splice-site variant (c.1066-11G>A) causing phenylalanine hydroxylase deficiency.
Splice donor variant (c.1066-11G>A) associated with severe phenylalanine hydroxylase deficiency and phenylketonuria.
Missense variant (p.Arg408Trp) causing severe classic phenylketonuria (PKU) when inherited bi-allelically due to profound loss of phenylalanine hydroxylase activity.