rs767203075

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 6P and 2B. PM1PM2PM5BP4_Moderate

The NM_005670.4(EPM2A):c.272G>A(p.Arg91Gln) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000846 in 1,537,496 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R91W) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000087 ( 0 hom. )

Consequence

EPM2A
NM_005670.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.26

Variant links:

Genes affected

EPM2A (HGNC:3413): (EPM2A glucan phosphatase, laforin) This gene encodes a dual-specificity phosphatase and may be involved in the regulation of glycogen metabolism. The protein acts on complex carbohydrates to prevent glycogen hyperphosphorylation, thus avoiding the formation of insoluble aggregates. Loss-of-function mutations in this gene have been associated with Lafora disease, a rare, adult-onset recessive neurodegenerative disease, which results in myoclonus epilepsy and usually results in death several years after the onset of symptoms. The disease is characterized by the accumulation of insoluble particles called Lafora bodies, which are derived from glycogen. [provided by RefSeq, Jan 2018]

EPM2A links:

EPM2A-DT (HGNC:):

EPM2A-DT links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 7 uncertain in NM_005670.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.

BP4

Computational evidence support a benign effect (MetaRNN=0.091126174).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
EPM2A	NM_005670.4 linkuse as main transcript	c.272G>A	p.Arg91Gln	missense_variant	1/4	ENST00000367519.9
EPM2A-DT	NR_038246.1 linkuse as main transcript	n.52+307C>T		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
EPM2A	ENST00000367519.9 linkuse as main transcript	c.272G>A	p.Arg91Gln	missense_variant	1/4	1	NM_005670.4	P1	O95278-1

Frequencies

GnomAD3 genomes

AF:

0.00000659

AC:

AN:

151702

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000194

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:

0.0000549

AC:

AN:

163796

Hom.:

AF XY:

0.0000669

AC XY:

AN XY:

89628

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000768

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:

0.00000866

AC:

AN:

1385794

Hom.:

Cov.:

AF XY:

0.0000102

AC XY:

AN XY:

685906

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000263

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000186

Gnomad4 OTH exome

AF:

0.0000177

GnomAD4 genome

AF:

0.00000659

AC:

AN:

151702

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74096

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000194

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000151

ExAC

AF:

0.0000601

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Progressive myoclonic epilepsy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 08, 2022

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on EPM2A protein function. ClinVar contains an entry for this variant (Variation ID: 580227). This variant has not been reported in the literature in individuals affected with EPM2A-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 91 of the EPM2A protein (p.Arg91Gln). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Benign

-0.14

BayesDel_noAF

Uncertain

-0.060

Cadd

Uncertain

Dann

Pathogenic

1.0

DEOGEN2

Uncertain

0.57

D;.;.;.

Eigen

Benign

0.096

Eigen_PC

Benign

0.063

FATHMM_MKL

Uncertain

0.81

LIST_S2

Uncertain

0.86

D;D;.;D

M_CAP

Pathogenic

0.96

MetaRNN

Benign

0.091

T;T;T;T

MetaSVM

Uncertain

0.19

MutationAssessor

Benign

1.8

L;L;L;L

MutationTaster

Benign

0.97

PrimateAI

Pathogenic

0.81

PROVEAN

Benign

-1.3

N;.;N;.

REVEL

Uncertain

0.38

Sift

Benign

0.058

T;.;T;.

Sift4G

Uncertain

0.053

T;D;.;.

Polyphen

0.99

D;P;P;.

Vest4

0.15

MutPred

0.42

Loss of MoRF binding (P = 0.0739);Loss of MoRF binding (P = 0.0739);Loss of MoRF binding (P = 0.0739);Loss of MoRF binding (P = 0.0739);

MVP

0.95

MPC

0.60

ClinPred

0.23

GERP RS

2.7

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

gMVP

0.69

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

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