Variant 1-45500346-T-A details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM1PM2PP3

The NM_015506.3(MMACHC):c.14T>A(p.Val5Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,812 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 Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. V5V) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.966

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 Uncertain_significance. Variant got 5 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;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.754

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MMACHC	NM_015506.3 linkuse as main transcript	c.14T>A	p.Val5Asp	missense_variant	1/4	ENST00000401061.9
MMACHC	NM_001330540.2 linkuse as main transcript	c.-209T>A		5_prime_UTR_variant	1/4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MMACHC	ENST00000401061.9 linkuse as main transcript	c.14T>A	p.Val5Asp	missense_variant	1/4	2	NM_015506.3	P1
MMACHC	ENST00000616135.1 linkuse as main transcript	c.-158T>A		5_prime_UTR_variant	1/5	2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000801

AC:

AN:

249574

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135398

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000579

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

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:

1461812

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

727202

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

Cov.:

Bravo

AF:

0.00000378

ExAC

AF:

0.00000827

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Cobalamin C disease

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 31, 2021

This sequence change replaces valine with aspartic acid at codon 5 of the MMACHC protein (p.Val5Asp). The valine residue is moderately conserved and there is a large physicochemical difference between valine and aspartic acid. This variant is present in population databases (rs780981680, ExAC 0.009%). This variant has not been reported in the literature in individuals affected with MMACHC-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.39

BayesDel_addAF

Pathogenic

0.19

BayesDel_noAF

Pathogenic

0.21

CADD

Uncertain

DANN

Uncertain

0.98

DEOGEN2

Benign

0.38

Eigen

Uncertain

0.31

Eigen_PC

Uncertain

0.27

FATHMM_MKL

Benign

0.69

LIST_S2

Benign

0.80

M_CAP

Pathogenic

0.61

MetaRNN

Pathogenic

0.75

MetaSVM

Pathogenic

0.83

MutationAssessor

Uncertain

2.3

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.54

PROVEAN

Uncertain

-2.9

REVEL

Pathogenic

0.72

Sift

Uncertain

0.0010

Sift4G

Pathogenic

0.0010

Polyphen

0.97

Vest4

0.61

MutPred

0.41

Gain of loop (P = 0.0013);

MVP

0.99

MPC

0.065

ClinPred

0.98

GERP RS

3.4

Varity_R

0.89

gMVP

0.91

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