rs796052000

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1PP5_Very_Strong

The NM_015506.3(MMACHC):c.328_331delAACC(p.Asn110AspfsTer13) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000018 in 1,613,980 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000016 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:10

Conservation

PhyloP100: 8.45

Publications

5 publications found

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 Gene-Disease associations (from GenCC):

methylmalonic aciduria and homocystinuria type cblC
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Myriad Women’s Health, ClinGen, G2P, Orphanet

MMACHC links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 16 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PP5

Variant 1-45508260-CCCAA-C is Pathogenic according to our data. Variant chr1-45508260-CCCAA-C is described in ClinVar as Pathogenic. ClinVar VariationId is 203835.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MMACHC	NM_015506.3 link	c.328_331delAACC	p.Asn110AspfsTer13	frameshift_variant	Exon 3 of 4	ENST00000401061.9	NP_056321.2
MMACHC	NM_001330540.2 link	c.157_160delAACC	p.Asn53AspfsTer13	frameshift_variant	Exon 3 of 4		NP_001317469.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMACHC	ENST00000401061.9 link	c.328_331delAACC	p.Asn110AspfsTer13	frameshift_variant	Exon 3 of 4	2	NM_015506.3	ENSP00000383840.4
MMACHC	ENST00000616135.1 link	c.157_160delAACC	p.Asn53AspfsTer13	frameshift_variant	Exon 3 of 5	2		ENSP00000478859.1

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152128

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000601

AC:

AN:

249456

AF XY:

0.0000369

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000377

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.0000164

AC:

AN:

1461852

Hom.:

AF XY:

0.0000124

AC XY:

AN XY:

727232

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.000380

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39698

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53418

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.00000270

AC:

AN:

1111980

Other (OTH)

AF:

0.0000331

AC:

AN:

60392

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.431

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000329

AC:

AN:

152128

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74320

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41412

American (AMR)

AF:

0.000196

AC:

AN:

15274

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10610

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68026

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.595

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000142

Hom.:

Bravo

AF:

0.0000831

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cobalamin C disease

Pathogenic:8

Dec 02, 2021

Fulgent Genetics, Fulgent Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 01, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Asn110Aspfs*13) in the MMACHC gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MMACHC are known to be pathogenic (PMID: 16311595). This variant is present in population databases (rs777767443, gnomAD 0.04%). This premature translational stop signal has been observed in individuals with methylmalonic aciduria and homocystinuria, cobalamin C (cblC) type (PMID: 16311595, 19370762, 23954310, 24126030). ClinVar contains an entry for this variant (Variation ID: 203835). For these reasons, this variant has been classified as Pathogenic. -

Apr 11, 2023

Genome-Nilou Lab

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Dec 19, 2024

Genomic Medicine Center of Excellence, King Faisal Specialist Hospital and Research Centre

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Feb 09, 2021

Revvity Omics, Revvity

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Apr 12, 2016

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: The c.328_331delAACC variant results in a premature termination codon, predicted to cause a truncated or absent MMACHC protein, which is a commonly known mechanism for disease. Truncations downstream of this position have also been associated with CBLC phenotype (e.g. p.Arg132X). One in-silico tool predicts damaging outcome for this variant. This variant is not found in approximately120716 control chromosomes from the large and broad populations of ExAC. This variant has been reported in several patients with CBLC. Multiple reputable databases and one clinical lab has classified this variant as pathogenic. Taken together, this variant has been classified as a Disease Variant/Pathogenic. -

Feb 23, 2024

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 16, 2017

Counsyl

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

not provided

Pathogenic:1

Aug 21, 2020

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 24126030, 23954310, 16311595, 19370762, 30157807) -

Methylmalonic acidemia with homocystinuria cblC

Pathogenic:1

Sep 16, 2020

Natera, Inc.

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

8.5

Mutation Taster

=2/198

disease causing (ClinVar)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over