5-7885818-G-A

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBS1_Supporting

The NM_002454.3(MTRR):c.1021G>A(p.Val341Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000841 in 1,614,058 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.00064 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00086 ( 1 hom. )

Consequence

MTRR
NM_002454.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 2.44

Publications

8 publications found

Variant links:

Genes affected

MTRR (HGNC:7473): (5-methyltetrahydrofolate-homocysteine methyltransferase reductase) This gene encodes a member of the ferredoxin-NADP(+) reductase (FNR) family of electron transferases. This protein functions in the synthesis of methionine by regenerating methionine synthase to a functional state. Because methionine synthesis requires methyl-group transfer by a folate donor, activity of the encoded enzyme is important for folate metabolism and cellular methylation. Mutations in this gene can cause homocystinuria-megaloblastic anemia, cbl E type. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, Dec 2015]

MTRR Gene-Disease associations (from GenCC):

methylcobalamin deficiency type cblE
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, G2P, Orphanet

MTRR links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -5 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.011435509).

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000644 (98/152176) while in subpopulation NFE AF = 0.00129 (88/67992). AF 95% confidence interval is 0.00108. There are 0 homozygotes in GnomAd4. There are 46 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MTRR	NM_002454.3 link	c.1021G>A	p.Val341Ile	missense_variant	Exon 7 of 15	ENST00000440940.7	NP_002445.2	Q9UBK8-2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MTRR	ENST00000440940.7 link	c.1021G>A	p.Val341Ile	missense_variant	Exon 7 of 15	1	NM_002454.3	ENSP00000402510.2		Q9UBK8-2

Frequencies

GnomAD3 genomes

AF:

0.000644

AC:

AN:

152058

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.0000944

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00128

Gnomad OTH

AF:

0.000479

GnomAD2 exomes

AF:

0.000616

AC:

155

AN:

251452

AF XY:

0.000692

show subpopulations

Gnomad AFR exome

AF:

0.000185

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.0000992

Gnomad EAS exome

AF:

0.000163

Gnomad FIN exome

AF:

0.000277

Gnomad NFE exome

AF:

0.00122

Gnomad OTH exome

AF:

0.000326

GnomAD4 exome

AF:

0.000861

AC:

1259

AN:

1461882

Hom.:

Cov.:

AF XY:

0.000847

AC XY:

616

AN XY:

727240

show subpopulations

African (AFR)

AF:

0.000149

AC:

AN:

33478

American (AMR)

AF:

0.0000224

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.0000383

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000504

AC:

AN:

39698

South Asian (SAS)

AF:

0.0000348

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.000168

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.000520

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00108

AC:

1200

AN:

1112006

Other (OTH)

AF:

0.000580

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.469

Heterozygous variant carriers

153

230

306

383

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

138

184

230

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000644

AC:

AN:

152176

Hom.:

Cov.:

AF XY:

0.000618

AC XY:

AN XY:

74382

show subpopulations

African (AFR)

AF:

0.000120

AC:

AN:

41520

American (AMR)

AF:

0.000131

AC:

AN:

15290

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000193

AC:

AN:

5172

South Asian (SAS)

AF:

0.000208

AC:

AN:

4818

European-Finnish (FIN)

AF:

0.0000944

AC:

AN:

10598

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00129

AC:

AN:

67992

Other (OTH)

AF:

0.00

AC:

AN:

2108

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.505

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000900

Hom.:

Bravo

AF:

0.000552

TwinsUK

AF:

0.00

AC:

ALSPAC

AF:

0.00182

AC:

ESP6500AA

AF:

0.000454

AC:

ESP6500EA

AF:

0.00163

AC:

ExAC

AF:

0.000692

AC:

Asia WGS

AF:

0.000577

AC:

AN:

3478

EpiCase

AF:

0.000709

EpiControl

AF:

0.00130

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Methylcobalamin deficiency type cblE

Uncertain:2

Jan 08, 2020

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Aug 16, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 341 of the MTRR protein (p.Val341Ile). This variant is present in population databases (rs74790259, gnomAD 0.1%), and has an allele count higher than expected for a pathogenic variant. This variant has not been reported in the literature in individuals affected with MTRR-related conditions. ClinVar contains an entry for this variant (Variation ID: 578634). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The isoleucine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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. -

Disorders of Intracellular Cobalamin Metabolism

Uncertain:1

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.072

BayesDel_addAF

Benign

-0.42

BayesDel_noAF

Benign

-0.39

CADD

Benign

8.4

(source)

DANN

Uncertain

0.99

Eigen

Benign

0.018

Eigen_PC

Benign

0.019

FATHMM_MKL

Uncertain

0.96

LIST_S2

Benign

0.65

T;T

M_CAP

Benign

0.014

MetaRNN

Benign

0.011

T;T

MetaSVM

Benign

-0.82

MutationAssessor

Benign

1.3

L;.

PhyloP100

2.4

PrimateAI

Benign

0.36

PROVEAN

Benign

-0.26

N;N

REVEL

Benign

0.20

Sift

Benign

0.32

T;T

Sift4G

Benign

0.58

T;T

Vest4

0.092

MVP

0.60

MPC

0.076

ClinPred

0.038

GERP RS

4.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.060

gMVP

0.25

Mutation Taster

=76/24

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over