6-49440318-G-A

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1PM2PM5PP2PP3_ModeratePP5_Very_Strong

The NM_000255.4(MMUT):c.1844C>T(p.Pro615Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,740 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. P615R) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MMUT
NM_000255.4 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 7.76

Publications

0 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 17 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 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 chr6-49440319-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 1685951.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, 0.893

PP5

Variant 6-49440318-G-A is Pathogenic according to our data. Variant chr6-49440318-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 1459268.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.1844C>T	p.Pro615Leu	missense_variant	Exon 11 of 13	ENST00000274813.4	NP_000246.2	P22033A0A024RD82B2R6K1
MMUT	XM_005249143.4 link	c.1844C>T	p.Pro615Leu	missense_variant	Exon 11 of 13		XP_005249200.1	P22033A0A024RD82

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMUT	ENST00000274813.4 link	c.1844C>T	p.Pro615Leu	missense_variant	Exon 11 of 13	1	NM_000255.4	ENSP00000274813.3		P22033

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461740

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727180

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33472

American (AMR)

AF:

0.00

AC:

AN:

44694

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26128

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53412

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111924

Other (OTH)

AF:

0.00

AC:

AN:

60390

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.325

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:1

Sep 22, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces proline with leucine at codon 615 of the MUT protein (p.Pro615Leu). The proline residue is highly conserved and there is a moderate physicochemical difference between proline and leucine. This variant is not present in population databases (ExAC no frequency). This missense change has been observed in individuals with methylmalonic aciduria (PMID: 16435223, 22727635, 27167370). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive. Experimental studies have shown that this missense change affects MUT function (PMID: 25125334). For these reasons, this variant has been classified as Pathogenic. -

Methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency

Pathogenic:1

Jun 28, 2025

Immunogenetics and Transplant Biology Service, University Hospital "Città della Salute e della Scienza di Torino"

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

0.84

BayesDel_addAF

Pathogenic

0.50

BayesDel_noAF

Pathogenic

0.49

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

0.83

Eigen_PC

Pathogenic

0.81

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.97

M_CAP

Uncertain

0.21

MetaRNN

Pathogenic

0.89

MetaSVM

Pathogenic

0.92

PhyloP100

7.8

PrimateAI

Uncertain

0.72

PROVEAN

Pathogenic

-9.8

REVEL

Pathogenic

0.87

Sift

Uncertain

0.013

Sift4G

Pathogenic

0.0

Vest4

0.84

MutPred

0.58

Loss of glycosylation at P615 (P = 0.0184);

MVP

0.99

MPC

0.33

ClinPred

1.0

GERP RS

4.8

gMVP

0.91

Mutation Taster

=15/85

disease causing

(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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over