MMAB rs756195708: What Your Genotype Means
The rs756195708 variant is a rare genetic change located within the MMAB gene. It is identified in clinical databases as a carrier mutation associated with methylmalonic aciduria type cblB, an autosomal recessive metabolic disorder.
What each genotype means
Typical MMAB gene profile
This genotype represents the common, expected sequence for the MMAB gene. It is not associated with the carrier status for methylmalonic aciduria type cblB.
This is the most common genotype found in the general population.
Carrier of cblB mutation
This genotype indicates you are a carrier of a specific mutation in the MMAB gene, sometimes referred to as a frameshift mutation (SER174FS). Carriers typically do not exhibit symptoms of methylmalonic aciduria type cblB, which is an autosomal recessive condition, but you should discuss the implications of this carrier status with a genetic counselor or healthcare provider.
This specific variant is rare in the general population.
Associated with cblB risk
This genotype indicates the presence of two copies of the variant, which is classified as pathogenic for methylmalonic aciduria type cblB. Individuals with this genotype may be at risk for the condition, and clinical evaluation is recommended to understand your specific health status.
This genotype is extremely rare in the general population.
Understanding the Variant and Its Location
The variant rs756195708 is a single nucleotide polymorphism (SNP) found on chromosome 12. Specifically, it is located within the MMAB gene, which provides instructions for making an enzyme essential for cellular metabolism. In genetic databases, this variant is often represented by the change from a cytosine (C) to a thymine (T) base. Because this variant is rare, it is not typically included in standard ancestry-based genetic testing panels unless specifically targeted. Its position within the gene is significant because mutations in this region can disrupt the normal production or function of the encoded protein. Understanding the location of such variants helps researchers determine how specific changes at the DNA level might impact biological processes, though the presence of a single variant does not necessarily indicate the presence of a clinical condition.
The Role of the MMAB Gene
The MMAB gene encodes the mitochondrial enzyme ATP:cobalamin adenosyltransferase. This enzyme plays a critical role in the body's ability to process vitamin B12. Specifically, it facilitates the conversion of cobalamin into adenosylcobalamin, a coenzyme required for the proper function of the enzyme methylmalonyl-CoA mutase. This pathway is vital for breaking down certain proteins and fats. When the MMAB gene is functioning correctly, the body can effectively manage these metabolic byproducts. However, when both copies of the gene contain pathogenic mutations, the resulting deficiency in adenosylcobalamin leads to the accumulation of toxic substances, such as methylmalonic acid, in the blood and tissues. This disruption is the underlying cause of methylmalonic aciduria type cblB, a condition that can lead to serious metabolic complications if not managed appropriately.
Research and Clinical Significance
Scientific research classifies rs756195708 as a pathogenic variant in the context of methylmalonic aciduria type cblB. Evidence from clinical databases, such as ClinVar, indicates that this specific change is associated with the condition. Because methylmalonic aciduria type cblB is an autosomal recessive disorder, an individual must typically inherit two pathogenic variants—one from each parent—to manifest the clinical symptoms of the disease. Carriers, who possess only one copy of the variant, generally do not exhibit symptoms of the condition. The evidence strength for this variant's association with the disease is considered moderate, reflecting its status as a known, albeit rare, genetic marker. It is important to note that genetic associations are based on statistical observations in populations and do not serve as a medical diagnosis for any individual.
Population Frequency and Interpretation
The rs756195708 variant is classified as rare across global populations. Because of its low frequency, it is not commonly encountered in the general population. When interpreting genetic data, it is essential to distinguish between being a carrier and having the condition itself. A carrier status means that an individual has one copy of the variant and one functional copy of the gene, which is typically sufficient for normal metabolic function. If you have received information regarding this variant, it is recommended to consult with a qualified healthcare provider or a genetic counselor. They can provide context based on your personal and family medical history, explain the implications of carrier status, and discuss whether further testing or clinical evaluation is appropriate for your specific situation.
How common is this variant?
The rs756195708 variant is considered rare in the general population, with limited data available regarding its specific distribution across different ancestral groups.
Frequently asked questions
What does it mean to be a carrier of a genetic variant?
Being a carrier means you have one copy of a gene variant that is associated with a recessive condition, while your other copy is functional. Carriers typically do not show symptoms of the condition but can pass the variant to their children.
Is methylmalonic aciduria type cblB treatable?
Methylmalonic aciduria type cblB is a metabolic disorder that requires specialized medical management. Treatment often involves dietary modifications and, in some cases, vitamin B12 supplementation, which should always be managed by a metabolic specialist.
Should I be worried if I have the C/T genotype?
The C/T genotype indicates carrier status, which generally does not cause health issues. However, you should discuss this result with a genetic counselor or your doctor to understand the implications for your family planning and health.
How is this variant detected?
This variant is typically identified through targeted genetic testing or comprehensive genomic sequencing. It is not usually included in standard health screenings unless specifically requested or indicated by family history.
Sources & further reading
Educational information only, last refreshed 9/19/2026. Not medical advice — these associations describe population statistics, not individual predictions.
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Pathogenic variant in the MMAB gene associated with autosomal recessive methylmalonic aciduria type cblB.
This variant is associated with carrier status for methylmalonic aciduria type cblB.
This variant is associated with carrier status for methylmalonic aciduria type cblB.
This variant is associated with carrier status for methylmalonic aciduria type cblB.