12-109573402-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_052845.4(MMAB):c.79C>T(p.Leu27Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000149 in 1,611,132 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000089 ( 0 hom. )

Consequence

MMAB
NM_052845.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 0.343

Variant links:

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]

MMAB links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.10137203).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
MMAB	NM_052845.4 linkuse as main transcript	c.79C>T	p.Leu27Phe	missense_variant	1/9	ENST00000545712.7
MVK	XM_047428873.1 linkuse as main transcript	c.117G>A	p.Glu39=	synonymous_variant	1/11
MVK	XM_017019313.3 linkuse as main transcript	c.-184G>A		5_prime_UTR_variant	1/10
MMAB	NR_038118.2 linkuse as main transcript	n.103C>T		non_coding_transcript_exon_variant	1/10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MMAB	ENST00000545712.7 linkuse as main transcript	c.79C>T	p.Leu27Phe	missense_variant	1/9	1	NM_052845.4	P1

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152242

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000217

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

Gnomad ASJ

AF:

0.000288

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

GnomAD3 exomes

AF:

0.0000167

AC:

AN:

238844

Hom.:

AF XY:

0.00000765

AC XY:

AN XY:

130790

show subpopulations

Gnomad AFR exome

AF:

0.000267

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS 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:

0.00000891

AC:

AN:

1458772

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

725600

show subpopulations

Gnomad4 AFR exome

AF:

0.000299

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:

0.00

Gnomad4 OTH exome

AF:

0.0000332

GnomAD4 genome

AF:

0.0000722

AC:

AN:

152360

Hom.:

Cov.:

AF XY:

0.0000805

AC XY:

AN XY:

74494

show subpopulations

Gnomad4 AFR

AF:

0.000216

Gnomad4 AMR

AF:

0.0000653

Gnomad4 ASJ

AF:

0.000288

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

Alfa

AF:

0.0000712

Hom.:

Bravo

AF:

0.0000680

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000165

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Methylmalonic aciduria, cblB type

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Apr 22, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Sep 01, 2021	This sequence change replaces leucine with phenylalanine at codon 27 of the MMAB protein (p.Leu27Phe). The leucine residue is moderately conserved and there is a small physicochemical difference between leucine and phenylalanine. This variant is present in population databases (rs150895111, ExAC 0.02%). This variant has not been reported in the literature in individuals affected with MMAB-related conditions. ClinVar contains an entry for this variant (Variation ID: 284358). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Inborn genetic diseases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 16, 2022

The c.79C>T (p.L27F) alteration is located in exon 1 (coding exon 1) of the MMAB gene. This alteration results from a C to T substitution at nucleotide position 79, causing the leucine (L) at amino acid position 27 to be replaced by a phenylalanine (F). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Eurofins Ntd Llc (ga)

Nov 07, 2015

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.074

BayesDel_addAF

Benign

-0.20

BayesDel_noAF

Benign

-0.23

Cadd

Benign

Dann

Uncertain

1.0

DEOGEN2

Benign

0.28

T;.;T

Eigen

Benign

-0.56

Eigen_PC

Benign

-0.63

FATHMM_MKL

Benign

0.53

LIST_S2

Benign

0.73

T;T;T

M_CAP

Benign

0.057

MetaRNN

Benign

0.10

T;T;T

MetaSVM

Benign

-0.66

MutationAssessor

Benign

1.8

L;.;.

MutationTaster

Benign

1.0

N;N

PrimateAI

Benign

0.36

PROVEAN

Benign

-0.64

N;.;.

REVEL

Benign

0.25

Sift

Benign

0.12

T;.;.

Sift4G

Benign

0.067

T;D;T

Polyphen

0.43

B;.;.

Vest4

0.27

MVP

0.93

MPC

0.39

ClinPred

0.26

GERP RS

1.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

Varity_R

0.039

gMVP

0.31

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over