NM_000255.4:c.977G>A

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PM1PM2PM5PP2PP3_StrongPP5_Very_Strong

The NM_000255.4(MMUT):c.977G>A(p.Arg326Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,142 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R326G) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

MMUT
NM_000255.4 missense

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:2

Conservation

PhyloP100: 7.57

Publications

2 publications found

Variant links:

Genes affected

MMUT (HGNC:7526): (methylmalonyl-CoA mutase) This gene encodes the mitochondrial enzyme methylmalonyl Coenzyme A mutase. In humans, the product of this gene is a vitamin B12-dependent enzyme which catalyzes the isomerization of methylmalonyl-CoA to succinyl-CoA, while in other species this enzyme may have different functions. Mutations in this gene may lead to various types of methylmalonic aciduria. [provided by RefSeq, Jul 2008]

MMUT Gene-Disease associations (from GenCC):

methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency
Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P
vitamin B12-unresponsive methylmalonic acidemia type mut-
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
vitamin B12-unresponsive methylmalonic acidemia type mut0
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

MMUT links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 19 ACMG points.

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_000255.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr6-49453692-T-C is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 427176.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP2

Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 150 curated pathogenic missense variants (we use a threshold of 10). The gene has 9 curated benign missense variants. Gene score misZ: 0.22855 (below the threshold of 3.09). Trascript score misZ: 1.0842 (below the threshold of 3.09). GenCC associations: The gene is linked to vitamin B12-unresponsive methylmalonic acidemia type mut-, methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency, vitamin B12-unresponsive methylmalonic acidemia type mut0.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.983

PP5

Variant 6-49453691-C-T is Pathogenic according to our data. Variant chr6-49453691-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 222926.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
MMUT	NM_000255.4 link	c.977G>A	p.Arg326Lys	missense_variant	Exon 5 of 13	ENST00000274813.4	NP_000246.2
MMUT	XM_005249143.4 link	c.977G>A	p.Arg326Lys	missense_variant	Exon 5 of 13		XP_005249200.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMUT	ENST00000274813.4 link	c.977G>A	p.Arg326Lys	missense_variant	Exon 5 of 13	1	NM_000255.4	ENSP00000274813.3

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251250

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.0000615

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461142

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726922

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33454

American (AMR)

AF:

0.00

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26112

East Asian (EAS)

AF:

0.00

AC:

AN:

39564

South Asian (SAS)

AF:

0.00

AC:

AN:

86244

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53406

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.00000180

AC:

AN:

1111528

Other (OTH)

AF:

0.00

AC:

AN:

60358

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome 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

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:1

Dec 04, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with lysine, which is basic and polar, at codon 326 of the MUT protein (p.Arg326Lys). This variant is present in population databases (rs758577372, gnomAD 0.007%). This missense change has been observed in individual(s) with methylmalonic aciduria (PMID: 27167370, 32754920). 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: 222926). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt MUT protein function with a positive predictive value of 95%. This variant disrupts the p.Arg326 amino acid residue in MUT. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 29158924, 30022420, 30712249). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency

Pathogenic:1

University Children's Hospital, University of Zurich

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.93

BayesDel_addAF

Pathogenic

0.45

BayesDel_noAF

Pathogenic

0.59

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.99

FATHMM_MKL

Uncertain

0.94

LIST_S2

Pathogenic

0.98

M_CAP

Pathogenic

0.58

MetaRNN

Pathogenic

0.98

MetaSVM

Pathogenic

0.95

PhyloP100

7.6

PrimateAI

Pathogenic

0.80

PROVEAN

Uncertain

-3.0

REVEL

Pathogenic

0.96

Sift

Pathogenic

0.0

Sift4G

Pathogenic

0.0

Vest4

0.98

MutPred

0.91

Loss of methylation at R326 (P = 0.1065);

MVP

1.0

MPC

0.49

ClinPred

1.0

GERP RS

5.6

gMVP

0.98

Mutation Taster

=14/86

disease causing (ClinVar)

(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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over