1-45507456-G-C

Position:

chr1-45507456-G-C

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 12P and 1B. PM1PM2PP5_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. R61Q) 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

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:

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 11 ACMG points.

PM1

In a chain Cyanocobalamin reductase / alkylcobalamin dealkylase (size 281) in uniprot entity MMAC_HUMAN there are 50 pathogenic changes around while only 14 benign (78%) in NM_015506.3

PM2

Very rare variant in population databases, with high coverage;

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/exons	MANE	UniProt
MMACHC	NM_015506.3 linkuse as main transcript	c.182G>C	p.Arg61Pro	missense_variant	2/4	ENST00000401061.9
MMACHC	NM_001330540.2 linkuse as main transcript	c.11G>C	p.Arg4Pro	missense_variant	2/4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MMACHC	ENST00000401061.9 linkuse as main transcript	c.182G>C	p.Arg61Pro	missense_variant	2/4	2	NM_015506.3	P1
MMACHC	ENST00000616135.1 linkuse as main transcript	c.11G>C	p.Arg4Pro	missense_variant	2/5	2

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

GnomAD3 exomes

AF:

0.0000200

AC:

AN:

249474

Hom.:

AF XY:

0.0000148

AC XY:

AN XY:

135356

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 SAS exome

AF:

0.0000327

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

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000112

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152100

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74294

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.0000655

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

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

Likely pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Apr 11, 2023	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	May 28, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Aug 29, 2023	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. ClinVar contains an entry for this variant (Variation ID: 854802). This missense change has been observed in individual(s) with methylmalonic aciduria with homocystinuria due to cobalamin C deficiency (PMID: 28693988; Invitae). This variant is present in population databases (no rsID available, gnomAD 0.01%). 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). -
Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 07, 2024	- -

not provided

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jun 11, 2022

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: 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

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;.

MutationTaster

Benign

1.0

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

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

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