1-11796321-G-C

Variant names:

• chr1-11796321-G-C
• rs1801133
• NM_005957.5:c.665C>G
• MTHFR p.Ala222Gly

Germline classificationCancer classification (beta)

Variant summary

Our verdict is

Uncertain significance

+4 Uncertain · Hot

-7

-6

-1

0

+5

+6

+9

+10

BenignB

Likely BenignLB

UncertainVUS

Likely PathogenicLP

PathogenicP

. The variant received 4 ACMG points: 4P and 0B. O3_ModerateO6_SupportingO7_Supporting

The NM_005957.5(MTHFR):c.665C>G (p.Ala222Gly) variant causes a missense change involving the alteration of a conserved nucleotide. The variant is absent from the gnomAD population database at sites with sufficient sequencing coverage. In-silico predictor (REVEL) classifies this variant as likely damaging/oncogenic. Splicing prediction tools (SpliceAI) predict no significant impact on normal splicing. The affected nucleotide is highly conserved across species (PhyloP 100-way vertebrate score: 9.14). No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Other variants at the same amino acid position have been reported in ClinVar (not pathogenic): p.A222= (synonymous): Likely_benign (ClinVar VariationId 1658853, 1 star); p.A222V: Likely_benign (ClinVar VariationId 2194685, 1 star); p.A222V: drug_response (ClinVar VariationId 3520, 3 stars)

• Frequency: Genomes: not found (cov: 32)
• Consequence: MTHFR NM_005957.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.14
• Publications: 8626 publications found

Genes affected

MTHFR (HGNC:7436): (methylenetetrahydrofolate reductase) The protein encoded by this gene catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a co-substrate for homocysteine remethylation to methionine. Genetic variation in this gene influences susceptibility to occlusive vascular disease, neural tube defects, colon cancer and acute leukemia, and mutations in this gene are associated with methylenetetrahydrofolate reductase deficiency.[provided by RefSeq, Oct 2009]

MTHFR Gene-Disease associations (from GenCC):

• homocystinuria due to methylene tetrahydrofolate reductase deficiency

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, PanelApp Australia, ClinGen, G2P

Classification according to ACGS-UK Somatic Oncogenicity v2025

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• O3: Absent or extremely rare in gnomAD (AC ≤ 2) — O3 moderate; GnomAD: AF = absent, AC = 0 — absent/extremely rare (O3 moderate [+2])
• O6: Computational evidence supports a deleterious/oncogenic effect; Missense variant — primary computational scorer supports an oncogenic/deleterious effect
• O7: Supporting: cancerhotspots.org hit, critical domain, or missense neighbourhood hotspot; No cancerhotspots.org hit at this position; UniProt domain: 0 pathogenic, 0 benign.; ±8 AA neighbourhood: 3 pathogenic, 1 benign (OR vs. background: 11.7); Variant does not impact splicing — splice-hotspot path not applicable

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005957.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MTHFR	NM_005957.5	MANE Select	c.665C>G	p.Ala222Gly	missense	Exon 5 of 12	NP_005948.3
	MTHFR	NM_001330358.2		c.788C>G	p.Ala263Gly	missense	Exon 5 of 12	NP_001317287.1	P42898-2
	MTHFR	NM_001410750.1		c.785C>G	p.Ala262Gly	missense	Exon 5 of 12	NP_001397679.1	Q5SNW7

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MTHFR	ENST00000376590.9	TSL:1 MANE Select	c.665C>G	p.Ala222Gly	missense	Exon 5 of 12	ENSP00000365775.3	P42898-1
	MTHFR	ENST00000423400.7	TSL:1	c.785C>G	p.Ala262Gly	missense	Exon 5 of 12	ENSP00000398908.3	Q5SNW7
	MTHFR	ENST00000376592.6	TSL:1	c.665C>G	p.Ala222Gly	missense	Exon 5 of 12	ENSP00000365777.1	P42898-1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 40

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Pathogenic	0.46	D
BayesDel_noAF	Pathogenic	0.42
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.89	D
Eigen	Uncertain	0.39
Eigen_PC	Uncertain	0.41
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.94	D
M_CAP	Uncertain	0.20	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Pathogenic	0.81	D
MutationAssessor	Uncertain	2.6	M
PhyloP100		9.1
PrimateAI	Uncertain	0.58	T
PROVEAN	Uncertain	-2.5	N
REVEL	Pathogenic	0.79
Sift	Benign	0.15	T
Sift4G	Benign	0.17	T
PromoterAI		0.016	Neutral
Varity_R		0.60
gMVP		0.89
Mutation Taster		=41/59	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs1801133;

hg19: chr1-11856378;

ACMG debug oncogenicity

ACGS debug oncogenicity

ACMG debug germline

Submit to ClinVar