NM_052845.4:c.521C>G

Variant names:

• chr12-109561103-G-C
• NM_052845.4:c.521C>G

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP3

The NM_052845.4(MMAB):​c.521C>G​(p.Ser174Trp) variant causes a missense, splice region change. The variant allele was found at a frequency of 0.000000686 in 1,457,702 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: MMAB NM_052845.4 missense, splice_region
• Scores: Splicing: ADA: 0.9739
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.15

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MMAB	NM_052845.4	c.521C>G	p.Ser174Trp	missense_variant, splice_region_variant	Exon 7 of 9	ENST00000545712.7	NP_443077.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMAB	ENST00000545712.7	c.521C>G	p.Ser174Trp	missense_variant, splice_region_variant	Exon 7 of 9	1	NM_052845.4	ENSP00000445920.1

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome AF: 6.86e-7 AC: 1 AN: 1457702 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 725408

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 30

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.71
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.51
CADD	Pathogenic	34
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.84	D;.
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.78
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	0.98	D;D
M_CAP	Pathogenic	0.65	D
MetaRNN	Pathogenic	0.96	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.4	M;.
PrimateAI	Uncertain	0.60	T
PROVEAN	Pathogenic	-5.3	D;.
REVEL	Pathogenic	0.93
Sift	Uncertain	0.0040	D;.
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;.
Vest4		0.91
MutPred		0.79		Loss of disorder (P = 0.0135);.;
MVP		0.99
MPC		0.99
ClinPred		1.0	D
GERP RS		4.9
Varity_R		0.95
gMVP		0.93

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.97
dbscSNV1_RF	Pathogenic	0.77
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr12-109998908;