Evidence · Replicated

What the research found

In the cited research, the G allele at rs1801222 was associated with higher serum vitamin B12 concentrations in the studied cohorts.

AA: Lower average
AG: Middle
GG: Higher average

Modest effect

What the study found

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

Icelanders with serum B12 measured in clinical laboratories · 37,283 people · Table 1 (Icelandic column, rs1801222)

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	AGMiddle	GGHigher average
All regions2,504 people	5%	31%	64%
Africa661 people	4%	30%	66%
The Americas347 people	5%	30%	65%
East Asia504 people	1%	28%	71%
Europe503 people	9%	40%	51%
South Asia489 people	3%	27%	70%

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	25%13 of 53 copies read
First farmers6500 to 3000 BC	66%494 of 749 copies read
Bronze Age3000 to 1200 BC	61%400 of 655 copies read
Iron Age and Antiquity1200 BC to AD 600	68%672 of 987 copies read
Middle AgesAD 600 to 1500	70%284 of 405 copies read
Today1000 Genomes	71%715 of 1,006 copies

Neanderthal and Denisovan genomes

Altai Neanderthal: 2 copies
Vindija Neanderthal: 2 copies
Chagyrskaya Neanderthal: 2 copies
Denisovan: 2 copies

Neanderthals and Denisovans carried this letter too: it is the older of the two.

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. Damage in old DNA can fake this letter, so it is counted only from samples treated to remove that damage and from high-quality genomes. Ancient genomes from the Allen Ancient DNA Resource (AADR v66): 15,136 people.

rs1801222

The marker

Gene or region: CUBN
Marker: rs1801222
Location: Chromosome 10 · GRCh37 17,156,151 · GRCh38 17,114,152
Letters studied: A and G, with G 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: CUBN · rs1801222
Location: Chromosome 10 · GRCh37 17,156,151 · GRCh38 17,114,152
Studied allele: G
Published statistic: Effect allele G (EAF 0.593): Icelandic 0.11, P 1.1e-52; Inter99 0.14, P 7.6e-8; Health2006 0.17, P 2.9e-18; combined N 45,576, P 3.3e-75, I2 0 (Table 1); quantile-normalised scale (Table 1 legend). Icelandic B12 N 37,283; Danish 5,481 + 2,812 (Results, Methods); 0.11 SD per copy (Table 1 (Icelandic column, rs1801222))
1000 Genomes Project phase 3, people with 0, 1 and 2 copies: All regions 115 / 775 / 1614 · Africa 29 / 199 / 433 · The Americas 17 / 105 / 225 · East Asia 7 / 140 / 357 · Europe 46 / 199 / 258 · South Asia 16 / 132 / 341

See this card in the sample report

Limits

What it cannot tell you

The study measured total serum vitamin B12, not how much B12 the gut absorbs or the tissues receive.

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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