Variant 1-11796340-CCTT-C details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2PM4_Supporting

The ENST00000376590.9(MTHFR):c.643_645del(p.Lys215del) variant causes a inframe deletion change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,613,248 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MTHFR
ENST00000376590.9 inframe_deletion

Scores

Not classified

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts P:1U:2

Conservation

PhyloP100: 7.30

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 Uncertain_significance. Variant got 3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM4

Nonframeshift variant in NON repetitive region in ENST00000376590.9. Strenght limited to Supporting due to length of the change: 1aa.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MTHFR	NM_005957.5 linkuse as main transcript	c.643_645del	p.Lys215del	inframe_deletion	5/12	ENST00000376590.9	NP_005948.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MTHFR	ENST00000376590.9 linkuse as main transcript	c.643_645del	p.Lys215del	inframe_deletion	5/12	1	NM_005957.5	ENSP00000365775	A1	P42898-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152208

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000795

AC:

AN:

251490

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135918

show subpopulations

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461040

Hom.:

AF XY:

0.00000138

AC XY:

AN XY:

726852

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

9.00e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152208

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74362

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:

0.0000147

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Homocystinuria due to methylene tetrahydrofolate reductase deficiency

Pathogenic:1Uncertain:1

Pathogenic, no assertion criteria provided	clinical testing	University Children's Hospital, University of Zurich	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 24, 2022	This variant, c.643_645del, results in the deletion of 1 amino acid(s) of the MTHFR protein (p.Lys215del), but otherwise preserves the integrity of the reading frame. This variant is present in population databases (rs746353274, gnomAD 0.002%). This variant has been observed in individual(s) with severe methylenetetrahydrofolate reductase deficiency or homocystinuria (PMID: 25736335, 27768236). ClinVar contains an entry for this variant (Variation ID: 187878). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Jul 06, 2021

Variant summary: MTHFR c.643_645delAAG (p.Lys215del) results in an in-frame deletion that is predicted to remove one amino acid from the encoded protein. The variant allele was found at a frequency of 8e-06 in 251490 control chromosomes. c.643_645delAAG has been reported in the literature in individuals affected with Homocystinuria Due To Methylene Tetrahydrofolate Reductase Deficiency. In one case, the variant was reported in a patient with hyperhomocysteinemia who had less than 1.5% residual MTHFR activity in cultured fibroblasts cell lines, but also carried an additional MTHFR variant (c.391C>T), making conclusions about the functional significance of the variant of interest difficult to assess (Bruda_2015). Additonally, the variant was reported in a patient referred for pharmacogenetic analysis prior to chemotherapy initiation, who also displayed hyperhomocysteinemia (Palmirotta_2017). The patient also carried c.677C>T and c.1298A>C, variants known to be associated wiht decreased enzyme activity. Segregation studies showed the probands daughter to carry all three variants and displayed similar hyperhomocysteinemia, while the probands son carried only c.1298A>C as well as the variant of interest, and had normal biochemical values. Thus the authors concluced that the increased plamsa tHcy appeared to be most likely related to the c.677C>T variant, and that the c.643_645delAAG is not suggestive of a pathogenic effect. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. One laboratory classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as VUS. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

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

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

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