rs763935916

Variant summary

Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PVS1PS3PP5_Very_Strong

The NM_052845.4(MMAB):​c.197-1G>T variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.0000217 in 1,612,208 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 predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV001400676: Disruption of this splice site has been observed in individuals with methylmalonic aciduria cobalamin B type (PMID:16410054, 30022420)." and additional evidence is available in ClinVar.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000023 ( 0 hom. )

Consequence

MMAB
NM_052845.4 splice_acceptor, intron

Scores

5
1
Splicing: ADA: 1.000
2

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:13O:1

Conservation

PhyloP100: 6.94

Publications

5 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), Orphanet, ClinGen, Myriad Women’s Health, G2P

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 20 ACMG points.

PVS1
Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 6.5, offset of 10, new splice context is: ttttccacatggttttctAGtac. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
PS3
PS3 evidence extracted from ClinVar submissions: SCV001400676: Disruption of this splice site has been observed in individuals with methylmalonic aciduria cobalamin B type (PMID: 16410054, 30022420).; SCV000699779: The variant is present in the large, broad control population, ExAC with an allele frequency of 3/121374 (1/40458), which does not exceed the estimated maximum allele frequency for a pathogenic allele in this gene of 1/714 (0.0014). The variant was found in multiple affected individuals with an established diagnosis of methylmalonic aciduria. Fibroblast lines from homozygous carriers had decreased incorporation of label from [14C] propionate into cellular macromolecules and decreased synthesis of AdoCbl from exogenous [57Co]CNCb. PMID:12000742
PP5
Variant 12-109568864-C-A is Pathogenic according to our data. Variant chr12-109568864-C-A is described in ClinVar as Pathogenic. ClinVar VariationId is 219008.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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.
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
MMAB
NM_052845.4
MANE Select
c.197-1G>T
splice_acceptor intron
N/ANP_443077.1Q96EY8
MMAB
NR_038118.2
n.221-1G>T
splice_acceptor intron
N/A

Ensembl Transcripts

Sel.
GeneTranscriptTagsHGVScHGVSpEffectExon RankProteinUniProt
MMAB
ENST00000545712.7
TSL:1 MANE Select
c.197-1G>T
splice_acceptor intron
N/AENSP00000445920.1Q96EY8
MMAB
ENST00000878519.1
c.197-1G>T
splice_acceptor intron
N/AENSP00000548578.1
MMAB
ENST00000878520.1
c.197-1G>T
splice_acceptor intron
N/AENSP00000548579.1

Frequencies

GnomAD3 genomes
AF:
0.0000132
AC:
2
AN:
151900
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000207
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000398
AC:
10
AN:
251468
AF XY:
0.0000662
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000176
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000226
AC:
33
AN:
1460308
Hom.:
0
Cov.:
30
AF XY:
0.0000385
AC XY:
28
AN XY:
726624
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33446
American (AMR)
AF:
0.00
AC:
0
AN:
44714
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26126
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39690
South Asian (SAS)
AF:
0.000313
AC:
27
AN:
86212
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53420
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.00000450
AC:
5
AN:
1110576
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60358
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.436
Heterozygous variant carriers
0
3
6
8
11
14
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.0000132
AC:
2
AN:
151900
Hom.:
0
Cov.:
33
AF XY:
0.0000135
AC XY:
1
AN XY:
74190
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41374
American (AMR)
AF:
0.00
AC:
0
AN:
15266
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3464
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5200
South Asian (SAS)
AF:
0.000207
AC:
1
AN:
4830
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10474
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
67974
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.500
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.0000436
Hom.:
0
Bravo
AF:
0.00000756
ExAC
AF:
0.0000247
AC:
3

ClinVar

ClinVar submissions
Significance:Pathogenic
Revision:criteria provided, multiple submitters, no conflicts
View on ClinVar
Pathogenic
VUS
Benign
Condition
10
-
-
Methylmalonic aciduria, cblB type (11)
2
-
-
Methylmalonic acidemia (2)
1
-
-
Methylmalonic aciduria (1)

Computational scores

Source: dbNSFP v4.9

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.41
D
BayesDel_noAF
Pathogenic
0.40
CADD
Pathogenic
35
DANN
Uncertain
1.0
Eigen
Pathogenic
1.1
Eigen_PC
Pathogenic
0.96
FATHMM_MKL
Pathogenic
0.99
D
PhyloP100
6.9
GERP RS
4.9
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Mutation Taster
=0/100
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
0.93
SpliceAI score (max)
0.80
Details are displayed if max score is > 0.2
DS_AG_spliceai
0.61
Position offset: -11
DS_AL_spliceai
0.80
Position offset: -1

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

Publications

Other links and lift over

dbSNP: rs763935916; hg19: chr12-110006669; API
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