NM_015506.3:c.182G>C

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 13P and 1B. PM1PM2PP2PP5_Very_StrongBP4

The NM_015506.3(MMACHC):c.182G>C(p.Arg61Pro) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000496 in 1,613,980 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign 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. R61W) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.0000048 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 missense

Scores

Clinical Significance

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

MMACHC links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 12 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

PM2

Very rare variant in population databases, with high coverage;

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.

PP5

Variant 1-45507456-G-C is Pathogenic according to our data. 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.

BP4

Computational evidence support a benign effect (MetaRNN=0.21476391). . Strength limited to SUPPORTING due to the PP5.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MMACHC	NM_015506.3 link	c.182G>C	p.Arg61Pro	missense_variant	Exon 2 of 4	ENST00000401061.9	NP_056321.2	Q9Y4U1
MMACHC	NM_001330540.2 link	c.11G>C	p.Arg4Pro	missense_variant	Exon 2 of 4		NP_001317469.1	Q9Y4U1A0A0C4DGU2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMACHC	ENST00000401061.9 link	c.182G>C	p.Arg61Pro	missense_variant	Exon 2 of 4	2	NM_015506.3	ENSP00000383840.4		Q9Y4U1
MMACHC	ENST00000616135.1 link	c.11G>C	p.Arg4Pro	missense_variant	Exon 2 of 5	2		ENSP00000478859.1		A0A0C4DGU2

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152100

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000200

AC:

AN:

249474

AF XY:

0.0000148

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000116

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000479

AC:

AN:

1461880

Hom.:

Cov.:

AF XY:

0.00000550

AC XY:

AN XY:

727240

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33478

American (AMR)

AF:

0.000112

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1112008

Other (OTH)

AF:

0.00

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.518

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152100

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74294

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41410

American (AMR)

AF:

0.0000655

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4816

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68022

Other (OTH)

AF:

0.00

AC:

AN:

2086

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000151

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cobalamin C disease

Pathogenic:4

Jun 10, 2024

Fulgent Genetics, Fulgent Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 07, 2024

Baylor Genetics

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Feb 15, 2024

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 proline, which is neutral and non-polar, at codon 61 of the MMACHC protein (p.Arg61Pro). This variant is present in population databases (no rsID available, gnomAD 0.01%). This missense change has been observed in individual(s) with methylmalonic aciduria with homocystinuria due to cobalamin C deficiency (PMID: 28693988; Invitae). ClinVar contains an entry for this variant (Variation ID: 854802). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MMACHC protein function. For these reasons, this variant has been classified as Pathogenic. -

Apr 11, 2023

Genome-Nilou Lab

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not provided

Pathogenic:1

Jul 15, 2024

GeneDx

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 36105582, 28693988) -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.67

BayesDel_addAF

Benign

-0.021

BayesDel_noAF

Uncertain

-0.040

CADD

Benign

4.6

(source)

DANN

Benign

0.93

DEOGEN2

Uncertain

0.50

D;T

Eigen

Benign

-1.2

Eigen_PC

Benign

-1.3

FATHMM_MKL

Benign

0.21

LIST_S2

Benign

0.82

T;T

M_CAP

Benign

0.058

MetaRNN

Benign

0.21

T;T

MetaSVM

Uncertain

0.16

MutationAssessor

Uncertain

2.5

M;.

PhyloP100

-0.58

PrimateAI

Benign

0.21

PROVEAN

Uncertain

-2.8

D;.

REVEL

Uncertain

0.45

Sift

Benign

0.083

T;.

Sift4G

Uncertain

0.060

T;T

Polyphen

0.31

B;.

Vest4

0.41

MutPred

0.34

Loss of methylation at K64 (P = 0.0907);.;

MVP

0.58

MPC

0.020

ClinPred

0.26

GERP RS

-5.5

Varity_R

0.70

gMVP

0.79

Mutation Taster

=64/36

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

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

Publications

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NM_015506.3:c.182G>C

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over