12-109573365-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 4P and 4B. PM1 PM2 BP4_Strong

The NM_052845.4(MMAB):c.116G>A(p.Gly39Asp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000558 in 1,613,048 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (no stars).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: MMAB NM_052845.4 missense
• Clinical Significance: Uncertain significance no assertion criteria provided U:1
• Conservation: PhyloP100: 0.427

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM1: In a chain Corrinoid adenosyltransferase MMAB (size 217) in uniprot entity MMAB_HUMAN there are 32 pathogenic changes around while only 10 benign (76%) in NM_052845.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.058553696).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MMAB	NM_052845.4	c.116G>A	p.Gly39Asp	missense_variant	1/9	ENST00000545712.7
MVK	XM_047428873.1	c.80C>T	p.Ala27Val	missense_variant	1/11
MVK	XM_017019313.3	c.-221C>T		5_prime_UTR_variant	1/10
MMAB	NR_038118.2	n.140G>A		non_coding_transcript_exon_variant	1/10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MMAB	ENST00000545712.7	c.116G>A	p.Gly39Asp	missense_variant	1/9	1	NM_052845.4	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152218 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000548 AC: 8 AN: 1460830 Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4 AN XY: 726738

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000720

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152218 Hom.: 0 Cov.: 33 AF XY: 0.0000134 AC XY: 1 AN XY: 74364

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: no assertion criteria provided

Submissions by phenotype

Methylmalonic aciduria, cblB type Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Natera, Inc.

Apr 10, 2020

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.082
BayesDel_addAF	Benign	-0.011	T
BayesDel_noAF	Benign	-0.25
Cadd	Benign	20
Dann	Benign	0.93
DEOGEN2	Benign	0.18	T;.;T
Eigen	Benign	-0.85
Eigen_PC	Benign	-0.78
FATHMM_MKL	Benign	0.50	D
LIST_S2	Benign	0.64	T;T;T
M_CAP	Benign	0.033	D
MetaRNN	Benign	0.059	T;T;T
MetaSVM	Benign	-0.92	T
MutationAssessor	Benign	0.94	L;.;.
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.35	T
PROVEAN	Benign	-0.87	N;.;.
REVEL	Benign	0.17
Sift	Benign	0.15	T;.;.
Sift4G	Benign	0.19	T;T;T
Polyphen		0.0010	B;.;.
Vest4		0.19
MutPred		0.15		Gain of solvent accessibility (P = 0.0739);Gain of solvent accessibility (P = 0.0739);Gain of solvent accessibility (P = 0.0739);
MVP		0.64
MPC		0.29
ClinPred		0.16	T
GERP RS		0.79
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.10
gMVP		0.41

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

Other links and lift over

dbSNP: rs1466525448; hg19: chr12-110011170;