rs121918240

A SNP in the MMACHC gene on chromosome 1. Its most notable genotype is C;C: methylmalonic aciduria, cblC type

Gene
MMACHC
Location
Chr 145,508,282 (GRCh38)
Highest magnitude
8.0Very important
Tested on
AncestryDNA

Genotypes

As shown in 23andMe and AncestryDNA files.

On SNPedia: (C;C), (C;T), (T;T). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.

Notes

From SNPedia

Notes

C;C

This genotype represents two defective MMACHC gene alleles, leading to an inborn error of metabolism known as methylmalonic aciduria, cblC type.

C;T

Unaffected in absence of a second MMACHC gene mutation

Source and license

Adapted from rs121918240 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.

SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.