Genetic Variant NM_015506.3:c.331C>T (chr1-45508266-C-T) – ACMG Classification: Pathogenic (18 pts)

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_015506.3(MMACHC):c.331C>T(p.Arg111*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000533 in 1,614,030 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 Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: 𝑓 0.00011 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000048 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:15O:1

Conservation

PhyloP100: 2.05

Publications

46 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: G2P, Orphanet, ClinGen, Labcorp Genetics (formerly Invitae), Ambry Genetics, Myriad Women’s Health

MMACHC links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1

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

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 1-45508266-C-T is Pathogenic according to our data. Variant chr1-45508266-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 1424.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_015506.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MMACHC	NM_015506.3	MANE Select	c.331C>T	p.Arg111*	stop_gained	Exon 3 of 4	NP_056321.2	Q9Y4U1
	MMACHC	NM_001330540.2		c.160C>T	p.Arg54*	stop_gained	Exon 3 of 4	NP_001317469.1	A0A0C4DGU2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
MMACHC	ENST00000401061.9	TSL:2 MANE Select	c.331C>T	p.Arg111*	stop_gained	Exon 3 of 4	ENSP00000383840.4	Q9Y4U1
MMACHC	ENST00000616135.1	TSL:2	c.160C>T	p.Arg54*	stop_gained	Exon 3 of 5	ENSP00000478859.1	A0A0C4DGU2
MMACHC	ENST00000933807.1		c.136C>T	p.Arg46*	stop_gained	Exon 2 of 3	ENSP00000603866.1

Frequencies

GnomAD3 genomes

AF:

0.000105

AC:

AN:

152186

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000145

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:

0.000103

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000521

AC:

AN:

249450

AF XY:

0.0000665

show subpopulations

Gnomad AFR exome

AF:

0.000129

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:

0.0000795

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.0000479

AC:

AN:

1461844

Hom.:

Cov.:

AF XY:

0.0000536

AC XY:

AN XY:

727224

show subpopulations

African (AFR)

AF:

0.000119

AC:

AN:

33480

American (AMR)

AF:

0.0000671

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.0000252

AC:

AN:

39698

South Asian (SAS)

AF:

0.0000464

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53416

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.0000459

AC:

AN:

1111976

Other (OTH)

AF:

0.000116

AC:

AN:

60394

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.471

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:

0.000105

AC:

AN:

152186

Hom.:

Cov.:

AF XY:

0.0000942

AC XY:

AN XY:

74348

show subpopulations

African (AFR)

AF:

0.000145

AC:

AN:

41440

American (AMR)

AF:

0.000196

AC:

AN:

15272

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5198

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000103

AC:

AN:

68034

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.519

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:

0.0000627

Hom.:

Bravo

AF:

0.0000869

ESP6500AA

AF:

0.000256

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000745

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.000178

ClinVar

ClinVar submissions

Significance:Pathogenic

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

Cobalamin C disease (12)

Methylmalonic acidemia with homocystinuria cblC (1)

MMACHC-related disorder (1)

not provided (1)

Disorders of Intracellular Cobalamin Metabolism (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.44

BayesDel_noAF

Pathogenic

0.58

CADD

Pathogenic

(source)

DANN

Uncertain

0.99

Eigen

Uncertain

0.39

Eigen_PC

Uncertain

0.24

FATHMM_MKL

Uncertain

0.83

PhyloP100

2.0

Vest4

0.84

GERP RS

4.8

Mutation Taster

=1/199

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

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over