Variant rs1463495909 details in Genebe, Genetics Data Aggregator

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_StrongPM2PP5_Very_Strong

The NM_015506.3(MMACHC):c.567dup(p.Ile190TyrfsTer13) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,614,050 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★).

Frequency

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

Exomes 𝑓: 0.0000041 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 frameshift

Scores

Not classified

Clinical Significance

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

Conservation

PhyloP100: -0.737

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 Pathogenic. Variant got 14 ACMG points.

PVS1

Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.333 CDS is truncated, and there are 1 pathogenic variants in the truncated region.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 1-45508932-G-GT is Pathogenic according to our data. Variant chr1-45508932-G-GT is described in ClinVar as [Pathogenic]. Clinvar id is 556708.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MMACHC	NM_015506.3 linkuse as main transcript	c.567dup	p.Ile190TyrfsTer13	frameshift_variant	4/4	ENST00000401061.9	NP_056321.2
MMACHC	NM_001330540.2 linkuse as main transcript	c.396dup	p.Ile133TyrfsTer13	frameshift_variant	4/4		NP_001317469.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MMACHC	ENST00000401061.9 linkuse as main transcript	c.567dup	p.Ile190TyrfsTer13	frameshift_variant	4/4	2	NM_015506.3	ENSP00000383840	P1
MMACHC	ENST00000616135.1 linkuse as main transcript	c.396dup	p.Ile133TyrfsTer13	frameshift_variant	4/5	2		ENSP00000478859

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152158

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:

0.000192

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:

0.0000120

AC:

AN:

249560

Hom.:

AF XY:

0.0000222

AC XY:

AN XY:

135392

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000579

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000556

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:

0.00000410

AC:

AN:

1461892

Hom.:

Cov.:

AF XY:

0.00000688

AC XY:

AN XY:

727246

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000447

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

8.99e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152158

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74324

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000192

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000416

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:10

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Cobalamin C disease

Pathogenic:7

Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jan 08, 2023	Variant summary: MMACHC c.567dupT (p.Ile190TyrfsX13) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant allele was found at a frequency of 1.2e-05 in 249560 control chromosomes. c.567dupT has been reported in the literature in multiple individuals affected with Cobalamin C Disease (Methylmalonic Aciduria With Homocystinuria) (example, Ji_2019, Liu_2010). These data indicate that the variant is very likely to be associated with disease. Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. All laboratories classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Beijing Key Laboratry for Genetics of Birth Defects, Beijing Children's Hospital	Feb 28, 2020	- -
Pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Jul 28, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 05, 2024	- -
Pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Apr 11, 2023	- -
Pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Feb 14, 2018	- -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Dec 13, 2023	This sequence change creates a premature translational stop signal (p.Ile190Tyrfs13) in the MMACHC gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 93 amino acid(s) of the MMACHC protein. This variant is present in population databases (no rsID available, gnomAD 0.01%). This premature translational stop signal has been observed in individual(s) with clinical features of combined methylmalonic aciduria and homocystinuria (PMID: 21835369, 26149271, 27383490). 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: 556708). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. This variant disrupts a region of the MMACHC protein in which other variant(s) (p.Trp203) have been determined to be pathogenic (PMID: 16311595, 20631720, 23954310, 27383490, 28327205). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

not provided

Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Jun 06, 2024	PM3_very_strong, PS4_moderate, PVS1_strong -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jan 17, 2024	Frameshift variant predicted to result in abnormal protein length as the last 93 amino acids are replaced with 12 different amino acids, and other similar variants have been reported in HGMD; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 29098535, 21835369, 34102818, 35361390, 31697851, 30863077, 30564975, 32778825, 34539730, 27751223, 19370762, 30157807, 35085585, 32943488, 29731766, 34076870, 32005694, 33691766, 34392393, 35223700, 35314707, 31998365) -

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

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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