Evidence · Replicated

What the research found

In the cited research, the C allele at rs34324219 was associated with higher serum vitamin B12 concentrations in the studied cohorts.

AA: Lower average
AC: Middle
CC: Higher average

Clear effect

What the study found

In the study, each copy went with higher blood level of this vitamin on average.

Danish adults in the Inter99 population cohort · 5,481 people · Table 1 (Danish Inter99 column, rs34324219); N from Methods (Inter99 cohort description)

Evidence: Replicated genome-wide association with a coding variant
Who was studied: Icelandic and Danish adults

1000 Genomes Project

How common each genotype is

How common each genotype is in the 1000 Genomes Project, by region
Region	AALower average	ACMiddle	CCHigher average
All regions2,504 people	<1%	10%	90%
Africa661 people	<1%	9%	91%
The Americas347 people	<1%	13%	87%
East Asia504 people	Not seen	Not seen	All
Europe503 people	<1%	22%	78%
South Asia489 people	<1%	8%	92%

Among the 2,504 people of the 1000 Genomes Project, in five world regions. These percentages describe groups of people, never anyone’s chance of having a trait.

Ancient genomes

Through time

How often the studied letter was read in ancient people, era by era, in the region chosen.

Region

Through time: Europe
Before farmingbefore 6500 BC	92%45 of 49 copies read
First farmers6500 to 3000 BC	92%334 of 362 copies read
Bronze Age3000 to 1200 BC	92%245 of 265 copies read
Iron Age and Antiquity1200 BC to AD 600	89%551 of 622 copies read
Middle AgesAD 600 to 1500	91%583 of 644 copies read
Today1000 Genomes	88%890 of 1,006 copies

Neanderthal and Denisovan genomes

Altai Neanderthal: Not read
Vindija Neanderthal: Not read
Chagyrskaya Neanderthal: 2 copies
Denisovan: Not read

For most ancient people only one of their two copies can be read, so these counts are copies read, not people. Close relatives, repeated samples and samples the archive marks as unreliable are left out. Ancient genomes from the Allen Ancient DNA Resource (AADR v66): 15,136 people.

rs34324219

The marker

Gene or region: TCN1
Marker: rs34324219
Location: Chromosome 11 · GRCh37 59,623,378 · GRCh38 59,855,905
Letters studied: A and C, with C as the studied allele

A DNA Traits report reads this marker in your raw DNA file and shows which of the three genotypes is yours, with how common it is. It counts the copies of the studied allele; it does not measure the trait itself.

Marker: TCN1 · rs34324219
Location: Chromosome 11 · GRCh37 59,623,378 · GRCh38 59,855,905
Studied allele: C
Published statistic: Effect allele C (EAF 0.881): Icelandic 0.21, P 8.8e-71; Inter99 0.40, P 3.2e-23; Health2006 0.30, P 3.5e-24; combined N 45,576, P 1.1e-111; I2 70% (P 0.001) (Table 1). Jacobs 2024: A -0.275, P 2e-51 (GWAS Catalog GCST90448636); 0.4 SD per copy (Table 1 (Danish Inter99 column, rs34324219); N from Methods (Inter99 cohort description))
1000 Genomes Project phase 3, people with 0, 1 and 2 copies: All regions 6 / 250 / 2248 · Africa 1 / 58 / 602 · The Americas 1 / 44 / 302 · East Asia 0 / 0 / 504 · Europe 3 / 110 / 390 · South Asia 1 / 38 / 450

See this card in the sample report

Limits

What it cannot tell you

TCN1 makes haptocorrin, the protein that carries most of the B12 in serum, so this marker moves the measured total more than the B12 available to cells.

Genetic Architecture of Vitamin B12 and Folate Levels Uncovered Applying Deeply Sequenced Large Datasets (Grarup et al., 2013)

The same topic

More in Nutrition & metabolism

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