12-109573424-G-C

Variant names:

• chr12-109573424-G-C
• rs10774774
• NM_052845.4:c.57C>G

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 2P and 7B. PM2 BP4_Strong BP6_Moderate BP7

The NM_052845.4(MMAB):​c.57C>G​(p.Arg19Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★). Synonymous variant affecting the same amino acid position (i.e. R19R) has been classified as Benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: MMAB NM_052845.4 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: -0.0470
• 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
• mevalonic aciduria

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Labcorp Genetics (formerly Invitae), Orphanet
• 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: Likely_benign. The variant received -5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.68).
• BP6: Variant 12-109573424-G-C is Benign according to our data. Variant chr12-109573424-G-C is described in ClinVar as Likely_benign. ClinVar VariationId is 1582021.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP7: Synonymous conserved (PhyloP=-0.047 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MMAB	NM_052845.4	c.57C>G	p.Arg19Arg	synonymous_variant	Exon 1 of 9	ENST00000545712.7	NP_443077.1
MVK	XM_047428873.1	c.139G>C	p.Ala47Pro	missense_variant	Exon 1 of 11		XP_047284829.1
MMAB	NR_038118.2	n.81C>G		non_coding_transcript_exon_variant	Exon 1 of 10
MVK	XM_017019313.3	c.-162G>C		5_prime_UTR_variant	Exon 1 of 10		XP_016874802.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MMAB	ENST00000545712.7	c.57C>G	p.Arg19Arg	synonymous_variant	Exon 1 of 9	1	NM_052845.4	ENSP00000445920.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Methylmalonic aciduria, cblB type Benign:1

Oct 26, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.68
CADD	Benign	6.6
DANN	Benign	0.84
PhyloP100		-0.047
PromoterAI		-0.061	Neutral

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

Other links and lift over

dbSNP: rs10774774; hg19: chr12-110011229;