NM_000255.4:c.1553T>C

Variant names:

• chr6-49447677-A-G
• rs864309738
• NM_000255.4:c.1553T>C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PP3_Strong PP5_Moderate

The NM_000255.4(MMUT):​c.1553T>C​(p.Leu518Pro) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 11/19 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MMUT NM_000255.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1 O:1
• Conservation: PhyloP100: 8.86

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988
• PP5: Variant 6-49447677-A-G is Pathogenic according to our data. Variant chr6-49447677-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 218994.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MMUT	NM_000255.4	c.1553T>C	p.Leu518Pro	missense_variant	Exon 8 of 13	ENST00000274813.4	NP_000246.2
MMUT	XM_005249143.4	c.1553T>C	p.Leu518Pro	missense_variant	Exon 8 of 13		XP_005249200.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMUT	ENST00000274813.4	c.1553T>C	p.Leu518Pro	missense_variant	Exon 8 of 13	1	NM_000255.4	ENSP00000274813.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Nov 29, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt MUT protein function. 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. This sequence change replaces leucine, which is neutral and non-polar, with proline, which is neutral and non-polar, at codon 518 of the MUT protein (p.Leu518Pro). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with methylmalonic aciduria (PMID: 16281286). ClinVar contains an entry for this variant (Variation ID: 218994). -

Methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency Other:1

-

GeneReviews

Significance: not provided

Review Status: no classification provided

Collection Method: literature only

mut(0) enzymatic subtype when homozygous -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Pathogenic	0.61
CADD	Pathogenic	28
DANN	Pathogenic	1.0
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D
M_CAP	Pathogenic	0.61	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
PrimateAI	Uncertain	0.67	T
PROVEAN	Pathogenic	-6.5	D
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Vest4		0.75
MutPred		0.93		Gain of loop (P = 3e-04);
MVP		1.0
MPC		0.62
ClinPred		1.0	D
GERP RS		5.2
gMVP		0.97

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

Other links and lift over

dbSNP: rs864309738; hg19: chr6-49415390;