12-109573349-G-T

Variant names:

• chr12-109573349-G-T
• rs747649185
• NM_052845.4:c.132C>A

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_052845.4(MMAB):​c.132C>A​(p.Asp44Glu) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,460,962 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 18/24 in silico tools predict a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. D44D) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MMAB NM_052845.4 missense, splice_region
• Scores: Splicing: ADA: 0.01437
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.400
• Publications: 0 publications found

Genes affected

MMAB (HGNC:19331): (metabolism of cobalamin associated B) This gene encodes a protein that catalyzes the final step in the conversion of vitamin B(12) into adenosylcobalamin (AdoCbl), a vitamin B12-containing coenzyme for methylmalonyl-CoA mutase. Mutations in the gene are the cause of vitamin B12-dependent methylmalonic aciduria linked to the cblB complementation group. Alternatively spliced transcript variants have been found. [provided by RefSeq, Apr 2011]

MVK (HGNC:7530): (mevalonate kinase) This gene encodes the peroxisomal enzyme mevalonate kinase. Mevalonate is a key intermediate, and mevalonate kinase a key early enzyme, in isoprenoid and sterol synthesis. Mevalonate kinase deficiency caused by mutation of this gene results in mevalonic aciduria, a disease characterized psychomotor retardation, failure to thrive, hepatosplenomegaly, anemia and recurrent febrile crises. Defects in this gene also cause hyperimmunoglobulinaemia D and periodic fever syndrome, a disorder characterized by recurrent episodes of fever associated with lymphadenopathy, arthralgia, gastrointestinal dismay and skin rash. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2014]

MVK Gene-Disease associations (from GenCC):

• porokeratosis 3, disseminated superficial actinic type

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• hyperimmunoglobulinemia D with periodic fever

  Inheritance: AR Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, G2P
• mevalonate kinase deficiency

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• mevalonic aciduria

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae)
• disseminated superficial actinic porokeratosis

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• porokeratosis of Mibelli

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM1: In a chain Corrinoid adenosyltransferase MMAB (size 217) in uniprot entity MMAB_HUMAN there are 29 pathogenic changes around while only 7 benign (81%) in NM_052845.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.1081298).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_052845.4. 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
	MMAB	NM_052845.4	MANE Select	c.132C>A	p.Asp44Glu	missense splice_region	Exon 1 of 9	NP_443077.1	Q96EY8
	MMAB	NR_038118.2		n.156C>A		splice_region non_coding_transcript_exon	Exon 1 of 10

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MMAB	ENST00000545712.7	TSL:1 MANE Select	c.132C>A	p.Asp44Glu	missense splice_region	Exon 1 of 9	ENSP00000445920.1	Q96EY8
	MMAB	ENST00000878519.1		c.132C>A	p.Asp44Glu	missense splice_region	Exon 1 of 10	ENSP00000548578.1
	MMAB	ENST00000878520.1		c.132C>A	p.Asp44Glu	missense splice_region	Exon 1 of 8	ENSP00000548579.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD2 exomes AF: 0.00000405 AC: 1 AN: 246714 AF XY: 0.00000745

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: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1460962 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726792

African (AFR) AF: 0.00 AC: 0 AN: 33458

American (AMR) AF: 0.00 AC: 0 AN: 44708

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26126

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86218

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52836

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5718

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111852

Other (OTH) AF: 0.00 AC: 0 AN: 60356

GnomAD4 genome Cov.: 33

ExAC AF: 0.00000824 AC: 1

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Benign	-0.051	T
BayesDel_noAF	Benign	-0.31
CADD	Benign	19
DANN	Uncertain	1.0
DEOGEN2	Benign	0.13	T
Eigen	Benign	-0.43
Eigen_PC	Benign	-0.30
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Benign	0.59	T
M_CAP	Benign	0.055	D
MetaRNN	Benign	0.11	T
MetaSVM	Benign	-0.91	T
MutationAssessor	Benign	1.5	L
PhyloP100		0.40
PrimateAI	Benign	0.35	T
PROVEAN	Benign	-0.50	N
REVEL	Benign	0.18
Sift	Benign	0.28	T
Sift4G	Benign	0.57	T
Polyphen		0.0010	B
Vest4		0.048
MutPred		0.12		Gain of solvent accessibility (P = 0.1014)
MVP		0.83
MPC		0.21
ClinPred		0.24	T
GERP RS		1.5
PromoterAI		0.042	Neutral
Varity_R		0.058
gMVP		0.24
Mutation Taster		=92/8	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.014
dbscSNV1_RF	Benign	0.17
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

Other links and lift over

dbSNP: rs747649185; hg19: chr12-110011154;