rs200895671

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1PM2PM5PP3_StrongPP5_Very_Strong

The NM_015506.3(MMACHC):c.565C>A(p.Arg189Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000186 in 1,614,074 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. R189C) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 missense

Scores

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8

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 18 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-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2144244.Status of the report is criteria_provided_single_submitter, 1 stars.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.951

PP5

Variant 1-45508931-C-A is Pathogenic according to our data. Variant chr1-45508931-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 558690.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>A	p.Arg189Ser	missense_variant	4/4	ENST00000401061.9
MMACHC	NM_001330540.2 linkuse as main transcript	c.394C>A	p.Arg132Ser	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>A	p.Arg189Ser	missense_variant	4/4	2	NM_015506.3	P1
MMACHC	ENST00000616135.1 linkuse as main transcript	c.394C>A	p.Arg132Ser	missense_variant	4/5	2

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152180

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:

0.00000801

AC:

AN:

249562

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135396

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1461894

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727248

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

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:

152180

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74332

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:

0.0000340

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cobalamin C disease

Pathogenic:7

Likely pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Apr 11, 2023	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Jun 07, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Jun 01, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein	Nov 11, 2022	ACMG classification criteria: PS3 supporting, PM2 moderated, PM3 very strong, PP3 supporting -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 25, 2024	This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 189 of the MMACHC protein (p.Arg189Ser). This variant is present in population databases (rs200895671, gnomAD 0.006%). This missense change has been observed in individual(s) with methylmalonic aciduria and homocystinuria, cblC type (PMID: 16311595, 18164228, 18245139, 19760748, 24599607, 29294253). ClinVar contains an entry for this variant (Variation ID: 558690). 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. -
Pathogenic, criteria provided, single submitter	clinical testing	Mendelics	May 28, 2019	- -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Jul 16, 2021	- -

Methylmalonic acidemia with homocystinuria cblC

Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Natera, Inc.

Sep 16, 2020

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.91

BayesDel_addAF

Pathogenic

0.36

BayesDel_noAF

Pathogenic

0.45

Cadd

Benign

Dann

Uncertain

0.99

DEOGEN2

Pathogenic

0.87

D;T

Eigen

Benign

0.17

Eigen_PC

Benign

0.068

FATHMM_MKL

Benign

0.54

LIST_S2

Benign

0.85

D;D

M_CAP

Pathogenic

0.30

MetaRNN

Pathogenic

0.95

D;D

MetaSVM

Pathogenic

1.0

MutationAssessor

Pathogenic

3.1

M;.

MutationTaster

Benign

0.98

PrimateAI

Uncertain

0.60

PROVEAN

Uncertain

-3.8

D;.

REVEL

Pathogenic

0.80

Sift

Benign

0.097

T;.

Sift4G

Uncertain

0.020

D;D

Polyphen

1.0

D;.

Vest4

0.80

MutPred

0.81

Loss of helix (P = 0.028);.;

MVP

0.96

MPC

0.077

ClinPred

0.97

GERP RS

3.8

Varity_R

0.74

gMVP

0.94

Splicing

Name

Calibrated prediction

Score

Prediction

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

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