Genetic Variant MMAB:p.Arg186Arg (chr12-109561066-C-T) – ACMG Classification: Likely_benign (-3 pts)

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2BP4_StrongBP7

The NM_052845.4(MMAB):c.558G>A(p.Arg186Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. R186R) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 30)

Exomes 𝑓: 0.0 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

MMAB
NM_052845.4 synonymous

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 0.515

Publications

0 publications found

Variant links:

Genes affected

MMAB (HGNC:19331): (metabolism of cobalamin associated B) This gene encodes a protein that catalyzes the final step in the conversion of vitamin B(12) into adenosylcobalamin (AdoCbl), a vitamin B12-containing coenzyme for methylmalonyl-CoA mutase. Mutations in the gene are the cause of vitamin B12-dependent methylmalonic aciduria linked to the cblB complementation group. Alternatively spliced transcript variants have been found. [provided by RefSeq, Apr 2011]

MMAB Gene-Disease associations (from GenCC):

methylmalonic acidemia
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
methylmalonic aciduria, cblB type
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Myriad Women's Health, Orphanet, G2P

MMAB links:

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new If you want to explore the variant's impact on the transcript NM_052845.4, check out the Mutation Effect Viewer. This is especially useful for frameshift variants or if you want to visualize the effect of exon loss / intron retention.

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.55).

BP7

Synonymous conserved (PhyloP=0.515 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_052845.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MMAB	NM_052845.4	MANE Select	c.558G>A	p.Arg186Arg	synonymous	Exon 7 of 9	NP_443077.1	Q96EY8
	MMAB	NR_038118.2		n.669G>A		non_coding_transcript_exon	Exon 8 of 10

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
MMAB	ENST00000545712.7	TSL:1 MANE Select	c.558G>A	p.Arg186Arg	synonymous	Exon 7 of 9	ENSP00000445920.1	Q96EY8
MMAB	ENST00000878519.1		c.621G>A	p.Arg207Arg	synonymous	Exon 8 of 10	ENSP00000548578.1
MMAB	ENST00000878520.1		c.558G>A	p.Arg186Arg	synonymous	Exon 7 of 8	ENSP00000548579.1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Data not reliable, filtered out with message: AC0

AF:

0.00

AC:

AN:

1458932

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

726016

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39696

South Asian (SAS)

AF:

0.00

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

50506

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111996

Other (OTH)

AF:

0.00

AC:

AN:

60370

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.55

CADD

Benign

5.7

(source)

DANN

Benign

0.42

PhyloP100

0.52

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over