dbSNP rs1328584680: MMAA:p.Ala102Thr (chr4-145639443-G-A) – ACMG Classification: Likely_pathogenic (6 pts)

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_172250.3(MMAA):c.304G>A(p.Ala102Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000144 in 1,461,868 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 Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.000014 ( 0 hom. )

Consequence

MMAA
NM_172250.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:4

Conservation

PhyloP100: 9.51

Variant links:

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]

MMAA links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.97

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MMAA	NM_172250.3 link	c.304G>A	p.Ala102Thr	missense_variant	Exon 2 of 7	ENST00000649156.2	NP_758454.1	Q8IVH4
MMAA	NM_001375644.1 link	c.304G>A	p.Ala102Thr	missense_variant	Exon 2 of 7		NP_001362573.1
MMAA	XM_011531684.4 link	c.304G>A	p.Ala102Thr	missense_variant	Exon 2 of 7		XP_011529986.1	Q8IVH4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMAA	ENST00000649156.2 link	c.304G>A	p.Ala102Thr	missense_variant	Exon 2 of 7		NM_172250.3	ENSP00000497008.1		Q8IVH4

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000796

AC:

AN:

251320

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135848

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000144

AC:

AN:

1461868

Hom.:

Cov.:

AF XY:

0.0000179

AC XY:

AN XY:

727232

show subpopulations

Gnomad4 AFR exome

AF:

0.00

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:

0.0000180

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

Cov.:

Alfa

AF:

0.000102

Hom.:

Bravo

AF:

0.0000189

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Methylmalonic aciduria, cblA type

Pathogenic:1Uncertain:2

Feb 12, 2020

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Oct 12, 2022

Clinical Genetics, Synlab MVZ Humangenetik Freiburg

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant was found in an affected patient in trans to a known pathogenic truncating variant. The variant is present in the gnomAD database at extreme low frequency (2x het., gnomAd v.3.1.2) and affects a highly conserved residue. -

Dec 13, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 102 of the MMAA protein (p.Ala102Thr). This variant is present in population databases (no rsID available, gnomAD 0.0009%). This missense change has been observed in individual(s) with clinical features of MMAA-related conditions (internal data). ClinVar contains an entry for this variant (Variation ID: 523564). 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 MMAA protein function with a positive predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

not provided

Pathogenic:1Uncertain:1

Oct 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

MMAA: PM2, PM3, PP4:Moderate -

Aug 29, 2019

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at a significant frequency in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; Has not been previously published as pathogenic or benign to our knowledge -

Cataract;C1837397:Severe global developmental delay;C4551563:Microcephaly

Uncertain:1

Jan 01, 2017

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.91

BayesDel_addAF

Pathogenic

0.50

BayesDel_noAF

Pathogenic

0.48

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Pathogenic

0.89

D;.;D;D;D;D

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.99

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

1.0

.;D;.;.;D;D

M_CAP

Pathogenic

0.56

MetaRNN

Pathogenic

0.97

D;D;D;D;D;D

MetaSVM

Pathogenic

1.1

MutationAssessor

Pathogenic

3.8

H;.;H;H;H;.

PrimateAI

Uncertain

0.58

PROVEAN

Uncertain

-3.1

.;.;D;.;.;.

REVEL

Pathogenic

0.92

Sift

Uncertain

0.0020

.;.;D;.;.;.

Sift4G

Uncertain

0.0020

.;.;D;.;.;D

Polyphen

1.0

D;.;D;D;D;.

Vest4

0.96, 0.97

MutPred

0.85

Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);Loss of helix (P = 0.1299);

MVP

0.96

MPC

0.54

ClinPred

0.99

GERP RS

5.4

Varity_R

0.92

gMVP

0.77

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over