CBS rs2347044: What Your Genotype Means
The rs2347044 polymorphism is a common single nucleotide variant located within the CBS (cystathionine-beta-synthase) gene on chromosome 21. Research has linked this variant to modest shifts in plasma total homocysteine concentrations and transsulfuration pathway activity. However, evidence connecting it directly to distinct clinical outcomes remains limited and non-diagnostic.
What each genotype means
Typical homocysteine metabolism
This genotype represents the most common form of the CBS gene variant. Research suggests this version is associated with standard processing of homocysteine in the body. As this is a common variant, it is not considered a diagnostic indicator for health conditions.
This is the most frequent genotype observed across most global populations.
Varied homocysteine metabolism
Carrying one copy of the T allele may be associated with slight variations in how your body metabolizes homocysteine compared to the common CC genotype. Scientific evidence regarding the clinical significance of this specific variant is limited, and it is not a standalone predictor of health outcomes. Please consult with a healthcare provider if you have concerns about your homocysteine levels.
This genotype is carried by a significant portion of the population, with frequencies varying by ancestry.
Potential metabolic variation
Individuals with this genotype carry two copies of the variant allele, which has been studied for its potential association with differences in plasma homocysteine levels. The evidence linking this specific variant to clinical health outcomes remains limited and mixed across different studies. This result should not be used for medical diagnosis; discuss any health or nutritional concerns with a qualified clinician.
This genotype is less common than the CC or CT genotypes, occurring in a smaller percentage of the population depending on ethnic background.
Genetic Location and Molecular Biology
The single nucleotide polymorphism rs2347044 is mapped to human chromosome 21 within the cystathionine-beta-synthase (CBS) gene locus. At this specific genomic coordinate, an individual may carry either the ancestral major allele or an alternate minor allele (observed as a C/T transition on the forward strand). Unlike rare monogenic null mutations that disrupt the reading frame or abolish core catalytic residues, rs2347044 represents a benign common genetic variation. Because it falls within a complex regulatory context, genomic studies evaluate whether this polymorphism alters transcriptional efficiency, mRNA splicing stability, or cellular protein expression levels. Investigating common polymorphisms like rs2347044 helps researchers understand subtle biochemical variability in human metabolic pathways without implying severe physiological disruption.
The Biological Role of the CBS Enzyme
The CBS gene encodes cystathionine beta-synthase, a pivotal pyridoxal 5'-phosphate (vitamin B6)-dependent enzyme essential for human transsulfuration. Homocysteine is an intermediary amino acid generated during the breakdown of dietary methionine. Cellular metabolism processes homocysteine along two primary pathways: remethylation back to methionine (utilizing folate and vitamin B12) or irreversible diversion into the transsulfuration pathway via CBS. Through this second route, cystathionine beta-synthase condenses homocysteine with serine to form cystathionine, which downstream enzymes convert into cysteine and eventually the master antioxidant glutathione. Complete deficiency of CBS due to rare biallelic pathogenic mutations leads to classical homocystinuria, a severe inborn error of metabolism. In contrast, common CBS single nucleotide polymorphisms merely exert subtle modulation over baseline transsulfuration velocity.
Current Scientific Evidence and Limitations
Scientific investigations have evaluated rs2347044 primarily in the context of plasma total homocysteine fluctuations, cardiovascular risk markers, and nutrient-gene interactions. A number of candidate gene studies and metabolic evaluations have noted that carriage of the minor allele corresponds to slight statistical differences in circulating homocysteine levels or altered responsiveness to folate and B-vitamin exposure. However, the strength of evidence supporting a direct clinical phenotype is classified as limited. Genome-wide association studies (GWAS) frequently demonstrate that common variants in CBS account for only small fractions of overall variance in homocysteine levels compared to environmental factors such as dietary intake, renal function, smoking status, and sex. Findings have not been uniformly replicated across diverse global cohorts, emphasizing the multifactorial nature of metabolic traits.
Population Distribution and Ancestral Patterns
The rs2347044 single nucleotide polymorphism exhibits modest frequency variation among ancestral groups across the globe. Broad population genetics datasets such as gnomAD and the 1000 Genomes Project demonstrate that the minor allele generally maintains an overall frequency between approximately 0.05 and 0.15. In European and East Asian cohorts, the minor allele typically hovers toward the lower-to-middle portion of this range, meaning that homozygosity for the minor allele is relatively uncommon in the general public. In contrast, the major allele remains heavily predominant worldwide. These population differences reflect neutral evolutionary drift and historical demographic patterns rather than natural selection tied to disease susceptibility, reinforcing why population background must be considered when interpreting common genetic variants.
Navigating Personal Genetic Data
Discovering an rs2347044 genotype on a direct-to-consumer genetic profile is an educational observation rather than a medical diagnosis. Possessing one or two copies of the minor allele does not signify disease, nor does it indicate clinical CBS deficiency or severe hyperhomocysteinemia. Homocysteine homeostasis is influenced far more significantly by diet, age, kidney health, alcohol consumption, and systemic vitamin levels—specifically vitamins B6, B12, and folate—than by any individual common polymorphism. Consumers should never alter prescribed pharmaceutical regimens, discontinue treatments, or ingest high doses of vitamin supplements based solely on an unvalidated single-marker association. Any concerns regarding metabolic health or circulating homocysteine levels should be reviewed with a qualified healthcare provider or registered dietitian who can order standardized clinical blood tests.
How common is this variant?
The minor allele frequency for rs2347044 generally ranges between 0.05 and 0.15 across worldwide ancestral populations, with the vast majority of individuals carrying at least one copy of the major allele.
Frequently asked questions
Does having the rs2347044 variant mean I have homocystinuria?
No, having the rs2347044 variant does not mean you have homocystinuria. Classical homocystinuria is a severe, rare genetic disorder caused by loss-of-function pathogenic mutations that severely disrupt the CBS enzyme. In contrast, rs2347044 is a common, non-pathogenic variant associated only with minor statistical fluctuations in metabolic measurements.
Should I take vitamin B6 or folic acid if I carry rs2347044?
You should not start high-dose vitamin supplementation solely because of an rs2347044 test result. While the CBS enzyme requires vitamin B6 (pyridoxal 5'-phosphate) as a cofactor, dietary requirements should be assessed through standard clinical lab work and balanced nutrition. Always consult a healthcare professional before altering your nutritional supplement regimen.
Can rs2347044 accurately predict my blood homocysteine level?
No, rs2347044 alone cannot accurately predict circulating homocysteine levels. Blood homocysteine concentrations are primarily determined by overall dietary intake of folate, vitamin B12, and vitamin B6, along with kidney function, age, and lifestyle habits. Clinical blood testing is the only reliable method to assess actual homocysteine concentrations.
How does rs2347044 differ from MTHFR variants?
While both CBS and MTHFR influence homocysteine metabolism, they act on distinct arms of the pathway. The CBS enzyme directs homocysteine into the irreversible transsulfuration cascade to produce cysteine and glutathione, whereas MTHFR generates the active folate needed to recycle homocysteine back into methionine. Both genes harbor common variants that have modest metabolic associations rather than deterministic clinical effects.
Sources & further reading
Educational information only, last refreshed 9/7/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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