rs780014899

Variant names:

• chr1-11794539-CT-C
• rs780014899
• NM_005957.5:c.1167-2delA

Variant summary

Our verdict is Pathogenic. The variant received 22 ACMG points: 22P and 0B. PVS1 PS3 PM2 PP5_Very_Strong

The NM_005957.5(MTHFR):​c.1167-2delA variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,776 control chromosomes in the GnomAD database, with no homozygous occurrence. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV001584149: Studies have shown that disruption of this splice site results in skipping of exon 8 and introduces a premature termination codon (PMID:25736335).".

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MTHFR NM_005957.5 splice_acceptor, intron
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 7.47
• Publications: 1 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: G2P, ClinGen, Orphanet, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Pathogenic. The variant received 22 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 4.1, offset of -34, new splice context is: gtggcactgccctctgtcAGgag. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PS3: PS3 evidence extracted from ClinVar submissions: SCV001584149: Studies have shown that disruption of this splice site results in skipping of exon 8 and introduces a premature termination codon (PMID: 25736335).
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 1-11794539-CT-C is Pathogenic according to our data. Variant chr1-11794539-CT-C is described in ClinVar as Pathogenic. ClinVar VariationId is 187891.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.1167-2delA		splice_acceptor intron	N/A	NP_005948.3
	MTHFR	NM_001330358.2		c.1290-2delA		splice_acceptor intron	N/A	NP_001317287.1	P42898-2
	MTHFR	NM_001410750.1		c.1287-2delA		splice_acceptor intron	N/A	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.1167-2delA		splice_acceptor intron	N/A	ENSP00000365775.3	P42898-1
	MTHFR	ENST00000423400.7	TSL:1	c.1287-2delA		splice_acceptor intron	N/A	ENSP00000398908.3	Q5SNW7
	MTHFR	ENST00000376592.6	TSL:1	c.1167-2delA		splice_acceptor intron	N/A	ENSP00000365777.1	P42898-1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000799 AC: 2 AN: 250282 AF XY: 0.0000147

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000177

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461776 Hom.: 0 Cov.: 38 AF XY: 0.00 AC XY: 0 AN XY: 727210

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44720

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53326

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111996

Other (OTH) AF: 0.00 AC: 0 AN: 60392

GnomAD4 genome Cov.: 32

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

ClinVar submissions

Significance: Pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
3	-	-	Homocystinuria due to methylene tetrahydrofolate reductase deficiency (3)
1	-	-	Neural tube defects, folate-sensitive (1)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.5
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.98		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.45		Position offset: -38
DS_AL_spliceai		0.98		Position offset: -1

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

Other links and lift over

dbSNP: rs780014899; hg19: chr1-11854596;