chr1-45500333-A-G

Variant summary

Our verdict is Pathogenic. Variant got 20 ACMG points: 20P and 0B. PVS1PS1_ModeratePM2PP5_Very_Strong

The NM_015506.3(MMACHC):ā€‹c.1A>Gā€‹(p.Met1?) variant causes a start lost change. The variant allele was found at a frequency of 0.0000041 in 1,461,762 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 (ā˜…ā˜…).

Frequency

Genomes: not found (cov: 32)
Exomes š‘“: 0.0000041 ( 0 hom. )

Consequence

MMACHC
NM_015506.3 start_lost

Scores

8
5
3

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:5

Conservation

PhyloP100: 5.22
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]

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ACMG classification

Classification made for transcript

Verdict is Pathogenic. Variant got 20 ACMG points.

PVS1
Start lost variant, no new inframe start found.
PS1
Another start lost variant in NM_015506.3 (MMACHC) was described as [Pathogenic] in Lovd
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 1-45500333-A-G is Pathogenic according to our data. Variant chr1-45500333-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 381577.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
MMACHCNM_015506.3 linkuse as main transcriptc.1A>G p.Met1? start_lost 1/4 ENST00000401061.9 NP_056321.2
MMACHCNM_001330540.2 linkuse as main transcriptc.-222A>G 5_prime_UTR_variant 1/4 NP_001317469.1

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
MMACHCENST00000401061.9 linkuse as main transcriptc.1A>G p.Met1? start_lost 1/42 NM_015506.3 ENSP00000383840 P1
MMACHCENST00000616135.1 linkuse as main transcript upstream_gene_variant 2 ENSP00000478859

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD3 exomes
AF:
0.00000801
AC:
2
AN:
249570
Hom.:
0
AF XY:
0.0000148
AC XY:
2
AN XY:
135394
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000290
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.0000327
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000410
AC:
6
AN:
1461762
Hom.:
0
Cov.:
30
AF XY:
0.00000688
AC XY:
5
AN XY:
727190
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.0000224
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.0000232
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.00000270
Gnomad4 OTH exome
AF:
0.00
GnomAD4 genome
Cov.:
32
Bravo
AF:
0.00000378
ExAC
AF:
0.00000827
AC:
1

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:5
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Cobalamin C disease Pathogenic:3
Pathogenic, criteria provided, single submitterclinical testingCounsylMar 15, 2017- -
Pathogenic, criteria provided, single submitterclinical testingGenome-Nilou LabApr 11, 2023- -
Pathogenic, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpDec 26, 2023This sequence change affects the initiator methionine of the MMACHC mRNA. The next in-frame methionine is located at codon 58. This variant is present in population databases (rs758477536, gnomAD 0.003%). Disruption of the initiator codon has been observed in individuals with methylmalonic aciduria and homocystinuria (PMID: 16311595, 17768669, 19760748, 28693988). ClinVar contains an entry for this variant (Variation ID: 381577). For these reasons, this variant has been classified as Pathogenic. -
not provided Pathogenic:1
Pathogenic, criteria provided, single submitterclinical testingGeneDxAug 04, 2022Initiation codon variant in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 19370762, 25398587, 19573432, 17768669, 30157807, 29731766, 35314707, 33691766, 32943488, 35361390, 34102818, 30863077, 22560872) -
Methylmalonic acidemia with homocystinuria cblC Pathogenic:1
Pathogenic, no assertion criteria providedclinical testingNatera, Inc.Sep 16, 2020- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
0.54
D
BayesDel_noAF
Pathogenic
0.64
CADD
Uncertain
24
DANN
Uncertain
0.99
DEOGEN2
Benign
0.087
T
Eigen
Uncertain
0.60
Eigen_PC
Uncertain
0.60
FATHMM_MKL
Uncertain
0.91
D
LIST_S2
Uncertain
0.90
D
M_CAP
Pathogenic
0.98
D
MetaRNN
Pathogenic
0.99
D
MetaSVM
Pathogenic
0.99
D
MutationTaster
Benign
1.0
D
PROVEAN
Benign
-1.1
N
REVEL
Pathogenic
0.75
Sift
Pathogenic
0.0
D
Sift4G
Pathogenic
0.0
D
Polyphen
0.95
P
Vest4
0.96
MutPred
1.0
Loss of methylation at K4 (P = 0.105);
MVP
0.98
ClinPred
0.99
D
GERP RS
5.8
Varity_R
0.97
gMVP
0.63

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.

Other links and lift over

dbSNP: rs758477536; hg19: chr1-45966005; COSMIC: COSV68984607; COSMIC: COSV68984607; API