rs62000414

Positions:

• chr12-109568772-A-C
• chr12-109568772-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_052845.4(MMAB):​c.288T>G​(p.Ile96Met) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,460,746 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. I96I) has been classified as Benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: MMAB NM_052845.4 missense, splice_region
• Scores: Splicing: ADA: 0.00004103
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.266

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.909

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MMAB	NM_052845.4	c.288T>G	p.Ile96Met	missense_variant, splice_region_variant	3/9	ENST00000545712.7	NP_443077.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MMAB	ENST00000545712.7	c.288T>G	p.Ile96Met	missense_variant, splice_region_variant	3/9	1	NM_052845.4	ENSP00000445920.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1460746 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 726718

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: 0.00000450

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.17
CADD	Benign	19
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.58	D;T
Eigen	Benign	0.0042
Eigen_PC	Benign	-0.15
FATHMM_MKL	Uncertain	0.78	D
LIST_S2	Pathogenic	0.97	D;D
M_CAP	Pathogenic	0.33	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Uncertain	0.71	D
MutationAssessor	Pathogenic	3.0	M;.
PrimateAI	Benign	0.47	T
PROVEAN	Benign	-2.2	N;.
REVEL	Pathogenic	0.78
Sift	Uncertain	0.0030	D;.
Sift4G	Uncertain	0.0030	D;D
Polyphen		0.99	D;.
Vest4		0.82
MutPred		0.89		Gain of disorder (P = 0.0409);Gain of disorder (P = 0.0409);
MVP		0.95
MPC		0.79
ClinPred		0.98	D
GERP RS		-3.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.84
gMVP		0.79

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.000041
dbscSNV1_RF	Benign	0.10
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: rs62000414; hg19: chr12-110006577;