dbSNP rs749765738: MTHFR:c.1632+2T>G (chr1-11792276-A-C) – ACMG Classification: Pathogenic (12 pts)

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1_ModeratePM2PP5_Very_Strong

The NM_005957.5(MTHFR):c.1632+2T>G variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 152,206 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)

Consequence

MTHFR
NM_005957.5 splice_donor, intron

Scores

Splicing: ADA: 1.000

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6

Conservation

PhyloP100: 8.68

Variant links:

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 links:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 12 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.05175038 fraction of the gene. Cryptic splice site detected, with MaxEntScore 3.5, offset of -40, new splice context is: gaaGTacga. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 1-11792276-A-C is Pathogenic according to our data. Variant chr1-11792276-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 187897.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MTHFR	NM_005957.5 link	c.1632+2T>G		splice_donor_variant, intron_variant	Intron 10 of 11	ENST00000376590.9	NP_005948.3	P42898-1Q8IU67Q59GJ6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MTHFR	ENST00000376590.9 link	c.1632+2T>G		splice_donor_variant, intron_variant	Intron 10 of 11	1	NM_005957.5	ENSP00000365775.3		P42898-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152206

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD4 exome

Cov.:

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152206

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74344

show subpopulations

Gnomad4 AFR

AF:

0.00

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:

0.0000294

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000490

Hom.:

Bravo

AF:

0.00000378

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Homocystinuria due to methylene tetrahydrofolate reductase deficiency

Pathogenic:3

University Children's Hospital, University of Zurich

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Oct 27, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects a donor splice site in intron 10 of the MTHFR gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in MTHFR are known to be pathogenic (PMID: 25736335). This variant is present in population databases (rs749765738, gnomAD 0.007%). Disruption of this splice site has been observed in individual(s) with MTHFR deficiency (PMID: 25736335). This variant is also known as c.1644+2T>G. ClinVar contains an entry for this variant (Variation ID: 187897). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

Sep 16, 2020

Natera, Inc.

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Schizophrenia;C1856061:Homocystinuria due to methylene tetrahydrofolate reductase deficiency;C1866558:Neural tube defects, folate-sensitive;C3160733:Thrombophilia due to thrombin defect

Pathogenic:1

May 02, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Pathogenic:1

Oct 14, 2021

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Canonical splice site variant predicted to result in an in-frame deletion of a critical region; Not observed at a significant frequency in large population cohorts (Lek et al., 2016); This variant is associated with the following publications: (PMID: 29246599, 26872964, 25736335) -

Neural tube defects, folate-sensitive

Pathogenic:1

Feb 15, 2022

Baylor Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.60

BayesDel_noAF

Pathogenic

0.28

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.91

FATHMM_MKL

Pathogenic

0.98

GERP RS

5.2

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.93

SpliceAI score (max)

1.0

Details are displayed if max score is > 0.2

DS_DG_spliceai

0.69

Position offset: 42

DS_DL_spliceai

1.0

Position offset: 2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over