rs398124434

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong

The NM_052845.4(MMAB):​c.568C>T​(p.Arg190Cys) variant causes a missense change. The variant allele was found at a frequency of 0.00000989 in 1,415,906 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R190H) has been classified as Pathogenic.

Frequency

Genomes: not found (cov: 30)
Exomes 𝑓: 0.0000099 ( 0 hom. )

Consequence

MMAB
NM_052845.4 missense

Scores

15
3
1

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7O:1

Conservation

PhyloP100: 7.15

Publications

9 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 aciduria, cblB type
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, G2P, Myriad Women’s Health, Labcorp Genetics (formerly Invitae), Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PM1
In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 6 uncertain in NM_052845.4
PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr12-109561055-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 203819.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.995
PP5
Variant 12-109561056-G-A is Pathogenic according to our data. Variant chr12-109561056-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 96244.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
MMABNM_052845.4 linkc.568C>T p.Arg190Cys missense_variant Exon 7 of 9 ENST00000545712.7 NP_443077.1 Q96EY8

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
MMABENST00000545712.7 linkc.568C>T p.Arg190Cys missense_variant Exon 7 of 9 1 NM_052845.4 ENSP00000445920.1 Q96EY8

Frequencies

GnomAD3 genomes
Cov.:
30
GnomAD2 exomes
AF:
0.0000201
AC:
5
AN:
248952
AF XY:
0.0000222
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:
0.0000442
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000989
AC:
14
AN:
1415906
Hom.:
0
Cov.:
35
AF XY:
0.0000128
AC XY:
9
AN XY:
704076
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
32156
American (AMR)
AF:
0.00
AC:
0
AN:
43310
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
24408
East Asian (EAS)
AF:
0.00
AC:
0
AN:
36618
South Asian (SAS)
AF:
0.00
AC:
0
AN:
85812
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
47094
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5508
European-Non Finnish (NFE)
AF:
0.0000129
AC:
14
AN:
1083646
Other (OTH)
AF:
0.00
AC:
0
AN:
57354
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.464
Heterozygous variant carriers
0
1
2
4
5
6
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
Cov.:
30
Alfa
AF:
0.0000498
Hom.:
0
Bravo
AF:
0.00000378
ExAC
AF:
0.0000330
AC:
4
EpiCase
AF:
0.00
EpiControl
AF:
0.0000593

ClinVar

Significance: Pathogenic/Likely pathogenic
Submissions summary: Pathogenic:7Other:1
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Methylmalonic aciduria, cblB type Pathogenic:6Other:1
Jan 09, 2019
Counsyl
Significance:Likely pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Oct 13, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 190 of the MMAB protein (p.Arg190Cys). This variant is present in population databases (rs398124434, gnomAD 0.003%). This missense change has been observed in individuals with clinical features of methylmalonic aciduria cobalamin B type (PMID: 16410054, 24059531, 29039164). ClinVar contains an entry for this variant (Variation ID: 96244). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt MMAB protein function. Experimental studies have shown that this missense change affects MMAB function (PMID: 19625202, 29197662). This variant disrupts the p.Arg190 amino acid residue in MMAB. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 16410054, 16439175, 19625202; Invitae). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Apr 29, 2024
Fulgent Genetics, Fulgent Genetics
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

-
GeneReviews
Significance:not provided
Review Status:no classification provided
Collection Method:literature only

- -

Jun 01, 2021
Baumgartner lab, University Children's Hospital Zurich
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Mar 27, 2024
Baylor Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Oct 24, 2023
Department of Pathology and Laboratory Medicine, Sinai Health System
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:research

- -

not provided Pathogenic:1
May 02, 2017
Eurofins Ntd Llc (ga)
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.71
BayesDel_addAF
Pathogenic
0.54
D
BayesDel_noAF
Pathogenic
0.60
CADD
Pathogenic
33
DANN
Pathogenic
1.0
DEOGEN2
Pathogenic
0.86
D;.
Eigen
Pathogenic
1.0
Eigen_PC
Pathogenic
0.85
FATHMM_MKL
Uncertain
0.94
D
LIST_S2
Uncertain
0.97
D;D
M_CAP
Pathogenic
0.84
D
MetaRNN
Pathogenic
0.99
D;D
MetaSVM
Pathogenic
1.0
D
MutationAssessor
Pathogenic
4.8
H;.
PhyloP100
7.2
PrimateAI
Uncertain
0.75
T
PROVEAN
Pathogenic
-7.4
D;.
REVEL
Pathogenic
0.98
Sift
Pathogenic
0.0
D;.
Sift4G
Pathogenic
0.0
D;D
Polyphen
1.0
D;.
Vest4
0.96
MutPred
0.96
Loss of MoRF binding (P = 0.0011);.;
MVP
0.98
MPC
0.98
ClinPred
1.0
D
GERP RS
4.9
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7
Varity_R
0.96
gMVP
0.96
Mutation Taster
=5/95
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
Splicevardb
2.0
SpliceAI score (max)
0.0
Details are displayed if max score is > 0.2

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

Publications

Other links and lift over

dbSNP: rs398124434; hg19: chr12-109998861; COSMIC: COSV57169694; COSMIC: COSV57169694; API