chr12-109573346-C-A
Variant summary
Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PVS1PM2PP3_StrongPP5_Moderate
The NM_052845.4(MMAB):c.134+1G>T variant causes a splice donor change involving the alteration of a non-conserved nucleotide. 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 Likely pathogenic (★).
Frequency
Genomes: not found (cov: 33)
Consequence
MMAB
NM_052845.4 splice_donor
NM_052845.4 splice_donor
Scores
5
1
1
Splicing: ADA: 1.000
2
Clinical Significance
Conservation
PhyloP100: 3.38
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]
MVK (HGNC:7530): (mevalonate kinase) This gene encodes the peroxisomal enzyme mevalonate kinase. Mevalonate is a key intermediate, and mevalonate kinase a key early enzyme, in isoprenoid and sterol synthesis. Mevalonate kinase deficiency caused by mutation of this gene results in mevalonic aciduria, a disease characterized psychomotor retardation, failure to thrive, hepatosplenomegaly, anemia and recurrent febrile crises. Defects in this gene also cause hyperimmunoglobulinaemia D and periodic fever syndrome, a disorder characterized by recurrent episodes of fever associated with lymphadenopathy, arthralgia, gastrointestinal dismay and skin rash. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2014]
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ACMG classification
Classification made for transcript
Verdict is Pathogenic. Variant got 16 ACMG points.
PVS1
?
Splicing variant, LoF is a know mechanism of disease,
PM2
?
Very rare variant in population databases, with high coverage;
PP3
?
Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
PP5
?
Variant 12-109573346-C-A is Pathogenic according to our data. Variant chr12-109573346-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2715184.Status of the report is criteria_provided_single_submitter, 1 stars.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
MMAB | NM_052845.4 | c.134+1G>T | splice_donor_variant | ENST00000545712.7 | |||
MVK | XM_047428873.1 | c.61C>A | p.Pro21Thr | missense_variant | 1/11 | ||
MVK | XM_017019313.3 | c.-240C>A | 5_prime_UTR_variant | 1/10 | |||
MMAB | NR_038118.2 | n.158+1G>T | splice_donor_variant, non_coding_transcript_variant |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
MMAB | ENST00000545712.7 | c.134+1G>T | splice_donor_variant | 1 | NM_052845.4 | P1 |
Frequencies
GnomAD3 genomes ? Cov.: 33
GnomAD3 genomes
?
Cov.:
33
GnomAD4 exome Cov.: 30
GnomAD4 exome
Cov.:
30
GnomAD4 genome ? Cov.: 33
GnomAD4 genome
?
Cov.:
33
ClinVar
Significance: Likely pathogenic
Submissions summary: Pathogenic:1
Revision: criteria provided, single submitter
LINK: link
Submissions by phenotype
Methylmalonic aciduria, cblB type Pathogenic:1
Likely pathogenic, criteria provided, single submitter | clinical testing | Invitae | Jun 14, 2023 | In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. This variant has not been reported in the literature in individuals affected with MMAB-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 1 of the MMAB gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in MMAB are known to be pathogenic (PMID: 15781192, 16410054). - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
D
BayesDel_noAF
Pathogenic
Cadd
Pathogenic
Dann
Uncertain
Eigen
Pathogenic
Eigen_PC
Pathogenic
FATHMM_MKL
Pathogenic
D
MutationTaster
Benign
D;D
GERP RS
RBP_binding_hub_radar
RBP_regulation_power_radar
Splicing
Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
dbscSNV1_RF
Pathogenic
SpliceAI score (max)
Details are displayed if max score is > 0.2
DS_DL_spliceai
Position offset: 1
Find out detailed SpliceAI scores and Pangolin per-transcript scores at
Publications
No publications associated with this variant yet.