rs201777449

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 5P and 4B. PM1PM5PP2BP4_Strong

The NM_015506.3(MMACHC):​c.182G>A​(p.Arg61Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000185 in 1,613,980 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R61W) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00012 ( 0 hom., cov: 31)
Exomes 𝑓: 0.00019 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 missense

Scores

1
18

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: -0.579

Publications

7 publications found
Variant links:
Genes affected
MMACHC (HGNC:24525): (metabolism of cobalamin associated C) The exact function of the protein encoded by this gene is not known, however, its C-terminal region shows similarity to TonB, a bacterial protein involved in energy transduction for cobalamin (vitamin B12) uptake. Hence, it is postulated that this protein may have a role in the binding and intracellular trafficking of cobalamin. Mutations in this gene are associated with methylmalonic aciduria and homocystinuria type cblC. [provided by RefSeq, Oct 2009]
MMACHC Gene-Disease associations (from GenCC):
  • methylmalonic aciduria and homocystinuria type cblC
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Myriad Women’s Health, ClinGen, G2P, Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PM1
In a chain Cyanocobalamin reductase / alkylcobalamin dealkylase (size 281) in uniprot entity MMAC_HUMAN there are 38 pathogenic changes around while only 16 benign (70%) in NM_015506.3
PM5
Other missense variant is known to change same aminoacid residue: Variant chr1-45507456-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 854802.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
PP2
Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 28 curated pathogenic missense variants (we use a threshold of 10). The gene has 7 curated benign missense variants. Gene score misZ: -1.0759 (below the threshold of 3.09). Trascript score misZ: -0.13772 (below the threshold of 3.09). GenCC associations: The gene is linked to methylmalonic aciduria and homocystinuria type cblC.
BP4
Computational evidence support a benign effect (MetaRNN=0.061534762).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
MMACHCNM_015506.3 linkc.182G>A p.Arg61Gln missense_variant Exon 2 of 4 ENST00000401061.9 NP_056321.2 Q9Y4U1
MMACHCNM_001330540.2 linkc.11G>A p.Arg4Gln missense_variant Exon 2 of 4 NP_001317469.1 Q9Y4U1A0A0C4DGU2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
MMACHCENST00000401061.9 linkc.182G>A p.Arg61Gln missense_variant Exon 2 of 4 2 NM_015506.3 ENSP00000383840.4 Q9Y4U1
MMACHCENST00000616135.1 linkc.11G>A p.Arg4Gln missense_variant Exon 2 of 5 2 ENSP00000478859.1 A0A0C4DGU2

Frequencies

GnomAD3 genomes
AF:
0.000125
AC:
19
AN:
152100
Hom.:
0
Cov.:
31
show subpopulations
Gnomad AFR
AF:
0.0000483
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.0000942
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.000235
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.000144
AC:
36
AN:
249474
AF XY:
0.000185
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.000145
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.000230
Gnomad OTH exome
AF:
0.000495
GnomAD4 exome
AF:
0.000191
AC:
279
AN:
1461880
Hom.:
0
Cov.:
32
AF XY:
0.000199
AC XY:
145
AN XY:
727240
show subpopulations
African (AFR)
AF:
0.000119
AC:
4
AN:
33478
American (AMR)
AF:
0.000134
AC:
6
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.0000252
AC:
1
AN:
39700
South Asian (SAS)
AF:
0.000128
AC:
11
AN:
86254
European-Finnish (FIN)
AF:
0.0000749
AC:
4
AN:
53416
Middle Eastern (MID)
AF:
0.00139
AC:
8
AN:
5768
European-Non Finnish (NFE)
AF:
0.000201
AC:
223
AN:
1112008
Other (OTH)
AF:
0.000364
AC:
22
AN:
60396
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.507
Heterozygous variant carriers
0
18
37
55
74
92
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
10
20
30
40
50
<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:
0.000125
AC:
19
AN:
152100
Hom.:
0
Cov.:
31
AF XY:
0.000135
AC XY:
10
AN XY:
74294
show subpopulations
African (AFR)
AF:
0.0000483
AC:
2
AN:
41410
American (AMR)
AF:
0.00
AC:
0
AN:
15268
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5188
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4816
European-Finnish (FIN)
AF:
0.0000942
AC:
1
AN:
10612
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.000235
AC:
16
AN:
68022
Other (OTH)
AF:
0.00
AC:
0
AN:
2086
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.493
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

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:
0.000168
Hom.:
0
Bravo
AF:
0.000113
TwinsUK
AF:
0.000270
AC:
1
ALSPAC
AF:
0.000778
AC:
3
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000355
AC:
3
ExAC
AF:
0.000140
AC:
17
EpiCase
AF:
0.000164
EpiControl
AF:
0.000296

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Cobalamin C disease Uncertain:4
Jul 16, 2020
Natera, Inc.
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Apr 11, 2023
Genome-Nilou Lab
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Sep 12, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 61 of the MMACHC protein (p.Arg61Gln). This variant is present in population databases (rs201777449, gnomAD 0.03%). This variant has not been reported in the literature in individuals affected with MMACHC-related conditions. ClinVar contains an entry for this variant (Variation ID: 533860). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The glutamine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Jan 04, 2022
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

See cases Uncertain:1
Nov 14, 2019
Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

ACMG classification criteria: PM2, BP4 -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.064
BayesDel_addAF
Benign
-0.31
T
BayesDel_noAF
Benign
-0.38
CADD
Benign
0.043
DANN
Benign
0.87
DEOGEN2
Benign
0.28
T;T
Eigen
Benign
-1.5
Eigen_PC
Benign
-1.5
FATHMM_MKL
Benign
0.082
N
LIST_S2
Benign
0.65
T;T
M_CAP
Benign
0.0080
T
MetaRNN
Benign
0.062
T;T
MetaSVM
Uncertain
-0.12
T
MutationAssessor
Benign
0.94
L;.
PhyloP100
-0.58
PrimateAI
Benign
0.19
T
PROVEAN
Benign
-0.72
N;.
REVEL
Benign
0.23
Sift
Benign
0.39
T;.
Sift4G
Benign
0.31
T;T
Polyphen
0.0010
B;.
Vest4
0.074
MVP
0.48
MPC
0.011
ClinPred
0.012
T
GERP RS
-5.5
Varity_R
0.10
gMVP
0.28
Mutation Taster
=93/7
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.040
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: rs201777449; hg19: chr1-45973128; API