chr12-109565177-C-A

Position:

• chr12-109565177-C-A

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The ENST00000545712.7(MMAB):​c.291-1G>T variant causes a splice acceptor change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MMAB ENST00000545712.7 splice_acceptor
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 5.11

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 Pathogenic. Variant got 11 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 3, offset of 17, new splice context is: tatgtttgctctggaattAGtca. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 12-109565177-C-A is Pathogenic according to our data. Variant chr12-109565177-C-A is described in ClinVar as [Pathogenic]. Clinvar id is 1173991.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MMAB	NM_052845.4	c.291-1G>T		splice_acceptor_variant		ENST00000545712.7	NP_443077.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MMAB	ENST00000545712.7	c.291-1G>T		splice_acceptor_variant		1	NM_052845.4	ENSP00000445920	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Methylmalonic aciduria, cblB type Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Baumgartner lab, University Children's Hospital Zurich

Jun 01, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.28
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.76
FATHMM_MKL	Pathogenic	0.97	D
MutationTaster	Benign	1.0	D;D
GERP RS		4.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.95		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.95		Position offset: -1

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: chr12-110002982;