rs121918250

chr6-49451668-G-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PP3_Strong PP5_Moderate

The NM_000255.4(MMUT):c.1130C>A(p.Ala377Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 152,138 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 Likely pathogenic (★). Synonymous variant affecting the same amino acid position (i.e. A377A) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.000013 (0 hom., cov: 32)
• Consequence: MMUT NM_000255.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 10.0

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]

ACMG classification

Verdict is Pathogenic. Variant got 10 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 6 uncertain in NM_000255.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.991
• PP5: Variant 6-49451668-G-T is Pathogenic according to our data. Variant chr6-49451668-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1879.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MMUT	NM_000255.4	c.1130C>A	p.Ala377Glu	missense_variant	6/13	ENST00000274813.4
MMUT	XM_005249143.4	c.1130C>A	p.Ala377Glu	missense_variant	6/13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MMUT	ENST00000274813.4	c.1130C>A	p.Ala377Glu	missense_variant	6/13	1	NM_000255.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152138 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152138 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74318

Gnomad4 AFR AF: 0.0000483

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: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000227

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Feb 14, 2022

ClinVar contains an entry for this variant (Variation ID: 1879). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Experimental studies have shown that this missense change affects MUT function (PMID: 1977311, 7912889). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant is also known as Ala378Glu. This missense change has been observed in individual(s) with methylmalonic acidemia (PMID: 1977311, 27167370). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces alanine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 377 of the MUT protein (p.Ala377Glu). -

METHYLMALONIC ACIDURIA, mut(0) TYPE Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Nov 01, 1990

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
Cadd	Pathogenic	30
Dann	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.97
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.38	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	0.94	D
MutationTaster	Benign	1.0	A
PrimateAI	Uncertain	0.75	T
PROVEAN	Pathogenic	-4.5	D
REVEL	Pathogenic	0.96
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Vest4		0.98
MutPred		0.98		Loss of catalytic residue at A377 (P = 0.0739);
MVP		0.99
MPC		0.51
ClinPred		1.0	D
GERP RS		5.0
gMVP		0.99

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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

Other links and lift over

dbSNP: rs121918250; hg19: chr6-49419381; COSMIC: COSV51272620;