1-45508931-C-T

Position:

chr1-45508931-C-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1PM2PM5PP3_ModeratePP5_Very_Strong

The NM_015506.3(MMACHC):c.565C>T(p.Arg189Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000991 in 1,614,192 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. R189H) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000082 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3

Conservation

PhyloP100: 1.40

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 16 ACMG points.

PM1

In a helix (size 12) in uniprot entity MMAC_HUMAN there are 5 pathogenic changes around while only 1 benign (83%) in NM_015506.3

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-45508932-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 417857.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.899

PP5

Variant 1-45508931-C-T is Pathogenic according to our data. Variant chr1-45508931-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 876445.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MMACHC	NM_015506.3 linkuse as main transcript	c.565C>T	p.Arg189Cys	missense_variant	4/4	ENST00000401061.9
MMACHC	NM_001330540.2 linkuse as main transcript	c.394C>T	p.Arg132Cys	missense_variant	4/4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MMACHC	ENST00000401061.9 linkuse as main transcript	c.565C>T	p.Arg189Cys	missense_variant	4/4	2	NM_015506.3	P1
MMACHC	ENST00000616135.1 linkuse as main transcript	c.394C>T	p.Arg132Cys	missense_variant	4/5	2

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

152180

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000385

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000120

AC:

AN:

249562

Hom.:

AF XY:

0.00000739

AC XY:

AN XY:

135396

show subpopulations

Gnomad AFR exome

AF:

0.0000646

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000556

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000883

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000821

AC:

AN:

1461894

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

727248

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000101

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000450

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000263

AC:

AN:

152298

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74460

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000386

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000264

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cobalamin C disease

Pathogenic:3

Likely pathogenic, no assertion criteria provided	clinical testing	Natera, Inc.	Sep 10, 2019	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 17, 2024	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 28, 2023	This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 189 of the MMACHC protein (p.Arg189Cys). This variant is present in population databases (rs200895671, gnomAD 0.01%). This missense change has been observed in individual(s) with cobalamin C disease (PMID: 31279840). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 876445). 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. This variant disrupts the p.Arg189 amino acid residue in MMACHC. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 18164228, 18245139, 29294253). 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.31

BayesDel_addAF

Pathogenic

0.21

BayesDel_noAF

Pathogenic

0.29

CADD

Uncertain

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.88

D;T

Eigen

Benign

0.18

Eigen_PC

Benign

0.079

FATHMM_MKL

Benign

0.74

LIST_S2

Uncertain

0.93

D;D

M_CAP

Pathogenic

0.44

MetaRNN

Pathogenic

0.90

D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.1

M;.

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.67

PROVEAN

Pathogenic

-5.3

D;.

REVEL

Pathogenic

0.79

Sift

Uncertain

0.021

D;.

Sift4G

Uncertain

0.0020

D;D

Polyphen

1.0

D;.

Vest4

0.75

MVP

0.94

MPC

0.079

ClinPred

0.95

GERP RS

3.8

Varity_R

0.57

gMVP

0.91

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

Details are displayed if max score is > 0.2

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over