4-145655253-G-A

Position:

• chr4-145655253-G-A

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PP3_Strong PP5_Very_Strong

The NM_172250.3(MMAA):​c.1076G>A​(p.Arg359Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,614,008 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. R359G) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MMAA NM_172250.3 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3 O:1
• Conservation: PhyloP100: 9.60

Genes affected

MMAA (HGNC:18871): (metabolism of cobalamin associated A) The protein encoded by this gene is involved in the translocation of cobalamin into the mitochondrion, where it is used in the final steps of adenosylcobalamin synthesis. Adenosylcobalamin is a coenzyme required for the activity of methylmalonyl-CoA mutase. Defects in this gene are a cause of methylmalonic aciduria. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.987
• PP5: Variant 4-145655253-G-A is Pathogenic according to our data. Variant chr4-145655253-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 218979.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MMAA	NM_172250.3	c.1076G>A	p.Arg359Gln	missense_variant	7/7	ENST00000649156.2
MMAA	NM_001375644.1	c.1076G>A	p.Arg359Gln	missense_variant	7/7
MMAA	XM_011531684.4	c.1076G>A	p.Arg359Gln	missense_variant	7/7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MMAA	ENST00000649156.2	c.1076G>A	p.Arg359Gln	missense_variant	7/7		NM_172250.3	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152142 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

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 AF: 0.00000137 AC: 2 AN: 1461866 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727234

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152142 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74326

Gnomad4 AFR AF: 0.0000241

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: 0.00000378

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Methylmalonic aciduria, cblA type Pathogenic:3 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Mar 17, 2023	For these reasons, this variant has been classified as Pathogenic. Studies have shown that this missense change alters MMAA gene expression (PMID: 28497574). 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 MMAA protein function. ClinVar contains an entry for this variant (Variation ID: 218979). This missense change has been observed in individuals with cobalamin A type methylmalonic aciduria (PMID: 15523652, 28497574, 33453710). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 359 of the MMAA protein (p.Arg359Gln). -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Feb 14, 2024	- -
not provided, no classification provided	literature only	GeneReviews	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	May 17, 2019	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.59
BayesDel_addAF	Pathogenic	0.49	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	29
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.91	D;.;D;D;D;D
Eigen	Pathogenic	0.81
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	.;D;.;.;D;D
M_CAP	Uncertain	0.21	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D
MetaSVM	Pathogenic	0.95	D
MutationAssessor	Pathogenic	3.1	M;.;M;M;M;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.41	T
PROVEAN	Uncertain	-3.9	.;.;D;.;.;.
REVEL	Pathogenic	0.82
Sift	Pathogenic	0.0	.;.;D;.;.;.
Sift4G	Pathogenic	0.0	.;.;D;.;.;D
Polyphen		1.0	D;.;D;D;D;.
Vest4		0.73, 0.92
MutPred		0.97		Loss of MoRF binding (P = 0.0532);.;Loss of MoRF binding (P = 0.0532);Loss of MoRF binding (P = 0.0532);Loss of MoRF binding (P = 0.0532);Loss of MoRF binding (P = 0.0532);
MVP		0.96
MPC		0.60
ClinPred		0.99	D
GERP RS		5.8
Varity_R		0.97
gMVP		0.88

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: rs864309731; hg19: chr4-146576405;