rs796051998

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PM1PM2PM4_SupportingPP5_Very_Strong

The NM_015506.3(MMACHC):c.388_390delTAC(p.Tyr130del) variant causes a conservative inframe deletion change. The variant allele was found at a frequency of 0.0000396 in 1,614,200 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★).

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000042 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 conservative_inframe_deletion

Scores

Not classified

Clinical Significance

Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:10

Conservation

PhyloP100: 5.51

Publications

3 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 13 ACMG points.

PM1

In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 9 uncertain in NM_015506.3

PM2

Very rare variant in population databases, with high coverage;

PM4

Nonframeshift variant in NON repetitive region in NM_015506.3. Strenght limited to Supporting due to length of the change: 1aa.

PP5

Variant 1-45508316-TTAC-T is Pathogenic according to our data. Variant chr1-45508316-TTAC-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 203833.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.388_390delTAC	p.Tyr130del	conservative_inframe_deletion	Exon 3 of 4	ENST00000401061.9	NP_056321.2
MMACHC	NM_001330540.2 link	c.217_219delTAC	p.Tyr73del	conservative_inframe_deletion	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.388_390delTAC	p.Tyr130del	conservative_inframe_deletion	Exon 3 of 4	2	NM_015506.3	ENSP00000383840.4
MMACHC	ENST00000616135.1 link	c.217_219delTAC	p.Tyr73del	conservative_inframe_deletion	Exon 3 of 5	2		ENSP00000478859.1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152190

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000200

AC:

AN:

249426

AF XY:

0.0000222

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000442

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000417

AC:

AN:

1461892

Hom.:

AF XY:

0.0000481

AC XY:

AN XY:

727248

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.000128

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000423

AC:

AN:

1112010

Other (OTH)

AF:

0.0000497

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.464

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:

0.0000197

AC:

AN:

152308

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74472

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41570

American (AMR)

AF:

0.00

AC:

AN:

15294

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.000415

AC:

AN:

4820

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68022

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.500

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:

0.0000868

Hom.:

Bravo

AF:

0.0000189

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cobalamin C disease

Pathogenic:8

May 24, 2023

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:research

- -

Sep 23, 2021

Revvity Omics, Revvity

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Apr 22, 2022

Fulgent Genetics, Fulgent Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Feb 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant, c.388_390del, results in the deletion of 1 amino acid(s) of the MMACHC protein (p.Tyr130del), but otherwise preserves the integrity of the reading frame. This variant is present in population databases (rs771707283, gnomAD 0.004%). This variant has been observed in individual(s) with methylmalonic aciduria and homocystinuria due to cobalamin C deficiency (PMID: 16311595, 24126030; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 203833). For these reasons, this variant has been classified as Pathogenic. -

Dec 23, 2021

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

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: MMACHC c.388_390delTAC (p.Tyr130del) results in an in-frame deletion that is predicted to remove one amino acid from the encoded protein. The variant allele was found at a frequency of 2e-05 in 249426 control chromosomes. c.388_390delTAC has been reported in the literature as a homozygous and compound heterozygous genotype in multiple individuals affected with cobalamin C type Methylmalonic Acidemia With Homocystinuria (example, Bourque_2021, Lerner-Ellis_2006, Gizicki_2014). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Two clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Both laboratories classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Apr 11, 2023

Genome-Nilou Lab

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Nov 10, 2023

Daryl Scott Lab, Baylor College of Medicine

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 04, 2024

Baylor Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

MMACHC-related disorder

Pathogenic:1

Aug 18, 2022

PreventionGenetics, part of Exact Sciences

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The MMACHC c.388_390delTAC variant is predicted to result in an in-frame deletion (p.Tyr130del). This variant is a recurrent variant that has been reported in the homozygous state or along with a second pathogenic MMACHC variant in multiple individuals with confirmed methylmalonic aciduria, cblC type (Lerner-Ellis et al. 2006. PubMed ID: 16311595; Gizicki et al. 2013. PubMed ID: 24126030; Bourque et al. 2020. PubMed ID: 33473346). This variant is reported in 0.0044% of alleles in individuals of European (Non-Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/1-45973988-TTAC-T). This variant is interpreted as pathogenic. -

not provided

Pathogenic:1

Oct 23, 2014

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.388_390delTAC mutation has been reported previously in association with cblC deficiency (Lerner-Ellis, et al., 2006). This mutation causes the deletion of a Tyrosine codon at amino acid position 130, denoted p.Tyr130del. The variant is found in MMA-MET panel(s). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

5.5

Mutation Taster

=55/45

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