rs201777449

Positions:

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 6P and 4B. PM1PM2PM5BP4_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. 16/21 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. R61P) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.00012 ( 0 hom., cov: 31)

Exomes 𝑓: 0.00019 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 missense

Scores

Clinical Significance

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

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 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;

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.

BP4

Computational evidence support a benign effect (MetaRNN=0.061534762).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MMACHC	NM_015506.3 linkuse as main transcript	c.182G>A	p.Arg61Gln	missense_variant	2/4	ENST00000401061.9
MMACHC	NM_001330540.2 linkuse as main transcript	c.11G>A	p.Arg4Gln	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>A	p.Arg61Gln	missense_variant	2/4	2	NM_015506.3	P1
MMACHC	ENST00000616135.1 linkuse as main transcript	c.11G>A	p.Arg4Gln	missense_variant	2/5	2

Frequencies

GnomAD3 genomes

AF:

0.000125

AC:

AN:

152100

Hom.:

Cov.:

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

GnomAD3 exomes

AF:

0.000144

AC:

AN:

249474

Hom.:

AF XY:

0.000185

AC XY:

AN XY:

135356

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 SAS exome

AF:

0.0000654

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.:

Cov.:

AF XY:

0.000199

AC XY:

145

AN XY:

727240

show subpopulations

Gnomad4 AFR exome

AF:

0.000119

Gnomad4 AMR exome

AF:

0.000134

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.000128

Gnomad4 FIN exome

AF:

0.0000749

Gnomad4 NFE exome

AF:

0.000201

Gnomad4 OTH exome

AF:

0.000364

GnomAD4 genome

AF:

0.000125

AC:

AN:

152100

Hom.:

Cov.:

AF XY:

0.000135

AC XY:

AN XY:

74294

show subpopulations

Gnomad4 AFR

AF:

0.0000483

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.0000942

Gnomad4 NFE

AF:

0.000235

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000164

Hom.:

Bravo

AF:

0.000113

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.000778

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000355

AC:

ExAC

AF:

0.000140

AC:

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

Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Jul 16, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Apr 11, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 12, 2022	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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Jan 04, 2022	- -

See cases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein

Nov 14, 2019

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

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

LIST_S2

Benign

0.65

T;T

M_CAP

Benign

0.0080

MetaRNN

Benign

0.062

T;T

MetaSVM

Uncertain

-0.12

MutationAssessor

Benign

0.94

L;.

MutationTaster

Benign

1.0

PrimateAI

Benign

0.19

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

GERP RS

-5.5

Varity_R

0.10

gMVP

0.28

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

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