rs373398993

Positions:

• chr1-11796219-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_005957.5(MTHFR):​c.767T>A​(p.Ile256Asn) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 152,150 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: 𝑓 0.000013 (0 hom., cov: 32)
• Consequence: MTHFR NM_005957.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter P:1 U:1
• Conservation: PhyloP100: 8.52

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 7 uncertain in NM_005957.5
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.979

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MTHFR	NM_005957.5	c.767T>A	p.Ile256Asn	missense_variant	5/12	ENST00000376590.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MTHFR	ENST00000376590.9	c.767T>A	p.Ile256Asn	missense_variant	5/12	1	NM_005957.5	A1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152150 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251376 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135874

Gnomad AFR exome AF: 0.000123

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 30

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152150 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74314

Gnomad4 AFR AF: 0.0000483

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000712 Hom.: 0

Bravo AF: 0.0000113

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.0000165 AC: 2

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Homocystinuria due to methylene tetrahydrofolate reductase deficiency Pathogenic:1 Uncertain:1

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Mar 29, 2022	This sequence change replaces isoleucine, which is neutral and non-polar, with asparagine, which is neutral and polar, at codon 256 of the MTHFR protein (p.Ile256Asn). This variant is present in population databases (rs373398993, gnomAD 0.01%). This missense change has been observed in individual(s) with severe MTHFR deficiency (PMID: 25736335; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 187883). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Pathogenic, no assertion criteria provided	clinical testing	University Children's Hospital, University of Zurich	-	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.44
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.98	D;.;.;D;.;.;.
Eigen	Pathogenic	0.94
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.97	.;D;.;D;D;D;D
M_CAP	Pathogenic	0.66	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.9	H;.;.;H;.;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Pathogenic	0.79	T
PROVEAN	Pathogenic	-6.6	D;D;D;D;.;.;.
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D;D;D;D;.;.;.
Sift4G	Pathogenic	0.0	D;D;D;D;.;.;.
Polyphen		1.0	D;.;.;D;.;.;.
Vest4		0.99
MVP		1.0
MPC		1.3
ClinPred		1.0	D
GERP RS		5.1
Varity_R		0.97
gMVP		0.99

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

Publications

LitVar

Other links and lift over

dbSNP: rs373398993; hg19: chr1-11856276;