1-45508931-C-T

Variant names:

• chr1-45508931-C-T
• rs200895671
• NM_015506.3:c.565C>T

Variant summary

Our verdict is Pathogenic. The variant received 17 ACMG points: 17P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate PP5_Very_Strong

The NM_015506.3(MMACHC):​c.565C>T​(p.Arg189Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000991 in 1,614,192 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 Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R189S) has been classified as Likely pathogenic.

• Frequency:
  • Genomes: 𝑓 0.000026 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000082 (0 hom.)
• Consequence: MMACHC NM_015506.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 1.40
• Publications: 18 publications found

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

ACMG classification

Our verdict: Pathogenic. The variant received 17 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 13 uncertain in NM_015506.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr1-45508931-C-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 558690.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 28 curated pathogenic missense variants (we use a threshold of 10). The gene has 7 curated benign missense variants. Gene score misZ: -1.0759 (below the threshold of 3.09). Trascript score misZ: -0.13772 (below the threshold of 3.09). GenCC associations: The gene is linked to methylmalonic aciduria and homocystinuria type cblC.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.899
• PP5: Variant 1-45508931-C-T is Pathogenic according to our data. Variant chr1-45508931-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 876445.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.565C>T	p.Arg189Cys	missense	Exon 4 of 4	NP_056321.2	Q9Y4U1
	MMACHC	NM_001330540.2		c.394C>T	p.Arg132Cys	missense	Exon 4 of 4	NP_001317469.1	A0A0C4DGU2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MMACHC	ENST00000401061.9	TSL:2 MANE Select	c.565C>T	p.Arg189Cys	missense	Exon 4 of 4	ENSP00000383840.4	Q9Y4U1
	MMACHC	ENST00000616135.1	TSL:2	c.394C>T	p.Arg132Cys	missense	Exon 4 of 5	ENSP00000478859.1	A0A0C4DGU2
	MMACHC	ENST00000933807.1		c.370C>T	p.Arg124Cys	missense	Exon 3 of 3	ENSP00000603866.1

Frequencies

GnomAD3 genomes AF: 0.0000263 AC: 4 AN: 152180 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000385

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: 0.0000120 AC: 3 AN: 249562 AF XY: 0.00000739

Gnomad AFR exome AF: 0.0000646

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000556

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000883

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000821 AC: 12 AN: 1461894 Hom.: 0 Cov.: 31 AF XY: 0.00000688 AC XY: 5 AN XY: 727248

African (AFR) AF: 0.0000299 AC: 1 AN: 33480

American (AMR) AF: 0.0000224 AC: 1 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.000101 AC: 4 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000450 AC: 5 AN: 1112012

Other (OTH) AF: 0.0000166 AC: 1 AN: 60396

GnomAD4 genome AF: 0.0000263 AC: 4 AN: 152298 Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2 AN XY: 74460

African (AFR) AF: 0.0000241 AC: 1 AN: 41572

American (AMR) AF: 0.00 AC: 0 AN: 15292

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.000386 AC: 2 AN: 5188

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10612

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 292

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68022

Other (OTH) AF: 0.00 AC: 0 AN: 2110

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.0000264

ExAC AF: 0.0000165 AC: 2

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
3	-	-	Cobalamin C disease (3)
1	-	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.31
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Pathogenic	0.29
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.88	D
Eigen	Benign	0.18
Eigen_PC	Benign	0.079
FATHMM_MKL	Benign	0.74	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.44	D
MetaRNN	Pathogenic	0.90	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	3.1	M
PhyloP100		1.4
PrimateAI	Uncertain	0.67	T
PROVEAN	Pathogenic	-5.3	D
REVEL	Pathogenic	0.79
Sift	Uncertain	0.021	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.75
MVP		0.94
MPC		0.079
ClinPred		0.95	D
GERP RS		3.8
Varity_R		0.57
gMVP		0.91
Mutation Taster		=15/85	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs200895671; hg19: chr1-45974603; COSMIC: COSV53113426; COSMIC: COSV53113426;