rs796052430

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_005670.4(EPM2A):c.446T>C(p.Ile149Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000434 in 1,613,846 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. I149M) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

EPM2A
NM_005670.4 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 8.94

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:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
EPM2A	NM_005670.4 linkuse as main transcript	c.446T>C	p.Ile149Thr	missense_variant	2/4	ENST00000367519.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
EPM2A	ENST00000367519.9 linkuse as main transcript	c.446T>C	p.Ile149Thr	missense_variant	2/4	1	NM_005670.4	P1	O95278-1

Frequencies

GnomAD3 genomes

AF:

0.0000197

AC:

AN:

152196

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

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

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251330

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135844

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.00000274

AC:

AN:

1461650

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727116

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

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:

0.0000497

GnomAD4 genome

AF:

0.0000197

AC:

AN:

152196

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74342

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000196

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

Alfa

AF:

0.0000936

Hom.:

Bravo

AF:

0.0000416

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Oct 16, 2013

p.Ile149Thr (ATT>ACT): c.446 T>C in exon 2 of the EPM2A gene (NM_005670.3). The Ile149Thr missense change has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. It was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. This variant is a non-conservative amino acid substitution of a non-polar Isoleucine residue with a polar Threonine residue. It alters at a position that is not highly conserved across species; however, other nearby missense mutations (K140N and N148Y) have been reported in association with Lafora disease. In silico analysis predicts this variant is probably damaging to the protein structure/function. Therefore, based on the currently available information, it is unclear whether Ile149Thr is a disease-causing mutation or a rare benign variant. The variant is found in EPILEPSY panel(s). -

Progressive myoclonic epilepsy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jul 04, 2022

This sequence change replaces isoleucine, which is neutral and non-polar, with threonine, which is neutral and polar, at codon 149 of the EPM2A protein (p.Ile149Thr). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with EPM2A-related conditions. ClinVar contains an entry for this variant (Variation ID: 205439). 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: "Possibly Damaging"; Align-GVGD: "Class C0"). 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Uncertain

0.14

BayesDel_noAF

Uncertain

-0.040

Cadd

Uncertain

Dann

Uncertain

1.0

Eigen

Uncertain

0.49

Eigen_PC

Uncertain

0.57

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.94

D;D;.;D;.;.;D;.;D;.;D

M_CAP

Benign

0.029

MetaRNN

Uncertain

0.71

D;D;D;D;D;D;D;D;D;D;D

MetaSVM

Benign

-0.78

MutationTaster

Benign

1.0

PrimateAI

Uncertain

0.65

Polyphen

0.84, 0.90

.;P;.;P;.;P;.;.;.;.;.

Vest4

0.83, 0.86, 0.80

MutPred

0.65

.;Loss of stability (P = 0.0406);.;Loss of stability (P = 0.0406);.;Loss of stability (P = 0.0406);Loss of stability (P = 0.0406);.;.;.;.;

MVP

0.81

MPC

0.66

ClinPred

0.93

GERP RS

5.6

gMVP

0.71

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