chr6-145686275-C-A

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM2PM5PP3PP5_Moderate

The NM_005670.4(EPM2A):​c.323G>T​(p.Arg108Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,144 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R108H) has been classified as Uncertain significance.

Frequency

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

Consequence

EPM2A
NM_005670.4 missense

Scores

7
10
2

Clinical Significance

Likely pathogenic criteria provided, single submitter P:1

Conservation

PhyloP100: 7.54

Publications

4 publications found
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 Gene-Disease associations (from GenCC):
  • Lafora disease
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen, Genomics England PanelApp, PanelApp Australia

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
PM5
Other missense variant is known to change same aminoacid residue: Variant chr6-145686276-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 3100.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
PP3
MetaRNN computational evidence supports a deleterious effect, 0.817
PP5
Variant 6-145686275-C-A is Pathogenic according to our data. Variant chr6-145686275-C-A is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 3776858.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
EPM2ANM_005670.4 linkc.323G>T p.Arg108Leu missense_variant Exon 2 of 4 ENST00000367519.9 NP_005661.1

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
EPM2AENST00000367519.9 linkc.323G>T p.Arg108Leu missense_variant Exon 2 of 4 1 NM_005670.4 ENSP00000356489.3

Frequencies

GnomAD3 genomes
AF:
0.00000658
AC:
1
AN:
152026
Hom.:
0
Cov.:
32
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:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000398
AC:
1
AN:
251384
AF XY:
0.00000736
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 FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000879
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
Cov.:
32
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152144
Hom.:
0
Cov.:
32
AF XY:
0.0000134
AC XY:
1
AN XY:
74364
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41500
American (AMR)
AF:
0.00
AC:
0
AN:
15276
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5182
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4822
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10580
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
292
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68000
Other (OTH)
AF:
0.00
AC:
0
AN:
2112
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
ExAC
AF:
0.00000824
AC:
1

ClinVar

Significance: Likely pathogenic
Submissions summary: Pathogenic:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

Lafora disease Pathogenic:1
Jan 06, 2025
Broad Center for Mendelian Genomics, Broad Institute of MIT and Harvard
Significance:Likely pathogenic
Review Status:criteria provided, single submitter
Collection Method:curation

The p.Arg108Leu variant in EPM2A has been reported in two siblings, in the homozygous state, with Lafora disease (PMID: 31858178, 33773408), and has been identified in 0.001% (1/68000) of European (non-Finnish) chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP ID: rs202234583). Although this variant has been seen in the general population in a heterozygous state, its frequency is low enough to be consistent with a recessive carrier frequency. Computational prediction tools and conservation analyses suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. One additional likely pathogenic variant, resulting in a different amino acid change at the same position, p.Arg108Cys, has been reported in association with disease in ClinVar, slightly supporting that a change at this position may not be tolerated (Variation ID: 3100). The phenotype of two siblings homozygous for this variant are highly specific for Lafora disease based on biopsies showing Lafora bodies consistent with disease (PMID: 33773408). In summary, although additional studies are required to fully establish its clinical significance, this variant is likely pathogenic for autosomal recessive Lafora disease. ACMG/AMP Criteria applied: PP3_moderate, PP4, PM3_supporting, PM2_supporting, PM5_supporting (Richards 2015). -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
0.97
BayesDel_addAF
Pathogenic
0.42
D
BayesDel_noAF
Pathogenic
0.37
CADD
Pathogenic
29
DANN
Uncertain
1.0
DEOGEN2
Uncertain
0.46
T;.;.;.
Eigen
Uncertain
0.53
Eigen_PC
Uncertain
0.61
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.91
D;D;.;D
M_CAP
Uncertain
0.16
D
MetaRNN
Pathogenic
0.82
D;D;D;D
MetaSVM
Benign
-0.59
T
MutationAssessor
Uncertain
2.6
M;M;M;M
PhyloP100
7.5
PrimateAI
Uncertain
0.75
T
PROVEAN
Uncertain
-2.5
N;.;.;.
REVEL
Pathogenic
0.81
Sift
Uncertain
0.0030
D;.;.;.
Sift4G
Pathogenic
0.0
D;D;.;.
Polyphen
1.0
D;D;D;.
Vest4
0.92
MVP
0.93
MPC
0.98
ClinPred
0.99
D
GERP RS
5.8
PromoterAI
-0.036
Neutral
gMVP
0.90
Mutation Taster
=3/97
disease causing

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

Other links and lift over

dbSNP: rs202234583; hg19: chr6-146007411; API