20-10275514-G-A

Position:

chr20-10275514-G-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 3P and 5B. PM1PP2BP4BS2

The ENST00000254976.7(SNAP25):c.23G>A(p.Arg8His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000112 in 1,605,980 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. R8C) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0000055 ( 0 hom. )

Consequence

SNAP25
ENST00000254976.7 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 9.20

Variant links:

Genes affected

SNAP25 (HGNC:11132): (synaptosome associated protein 25) Synaptic vesicle membrane docking and fusion is mediated by SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) located on the vesicle membrane (v-SNAREs) and the target membrane (t-SNAREs). The assembled v-SNARE/t-SNARE complex consists of a bundle of four helices, one of which is supplied by v-SNARE and the other three by t-SNARE. For t-SNAREs on the plasma membrane, the protein syntaxin supplies one helix and the protein encoded by this gene contributes the other two. Therefore, this gene product is a presynaptic plasma membrane protein involved in the regulation of neurotransmitter release. Two alternative transcript variants encoding different protein isoforms have been described for this gene. [provided by RefSeq, Jul 2008]

SNAP25 links:

SNAP25-AS1 (HGNC:44312): (SNAP25 antisense RNA 1)

SNAP25-AS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

PM1

In a helix (size 72) in uniprot entity SNP25_HUMAN there are 12 pathogenic changes around while only 3 benign (80%) in ENST00000254976.7

PP2

Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SNAP25. . Gene score misZ 2.9553 (greater than the threshold 3.09). Trascript score misZ 3.1929 (greater than threshold 3.09). GenCC has associacion of gene with presynaptic congenital myasthenic syndrome, congenital myasthenic syndrome 18, developmental and epileptic encephalopathy.

BP4

Computational evidence support a benign effect (MetaRNN=0.41747436).

BS2

High AC in GnomAd4 at 10 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SNAP25	NM_130811.4 linkuse as main transcript	c.23G>A	p.Arg8His	missense_variant	2/8	ENST00000254976.7	NP_570824.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SNAP25	ENST00000254976.7 linkuse as main transcript	c.23G>A	p.Arg8His	missense_variant	2/8	1	NM_130811.4	ENSP00000254976	P5	P60880-1
SNAP25-AS1	ENST00000421143.6 linkuse as main transcript	n.6-78577C>T		intron_variant, non_coding_transcript_variant		5

Frequencies

GnomAD3 genomes

AF:

0.0000657

AC:

AN:

152222

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000217

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:

0.000478

GnomAD3 exomes

AF:

0.0000208

AC:

AN:

240598

Hom.:

AF XY:

0.0000154

AC XY:

AN XY:

129642

show subpopulations

Gnomad AFR exome

AF:

0.000198

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:

0.0000183

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000550

AC:

AN:

1453758

Hom.:

Cov.:

AF XY:

0.00000415

AC XY:

AN XY:

722434

show subpopulations

Gnomad4 AFR exome

AF:

0.0000599

Gnomad4 AMR exome

AF:

0.0000228

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000253

Gnomad4 SAS exome

AF:

0.0000237

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000181

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000657

AC:

AN:

152222

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74360

show subpopulations

Gnomad4 AFR

AF:

0.000217

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:

0.000478

Alfa

AF:

0.000129

Hom.:

Bravo

AF:

0.0000756

ESP6500AA

AF:

0.000227

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.0000330

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Sep 11, 2024

Variant summary: SNAP25 c.23G>A (p.Arg8His) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2.1e-05 in 240598 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.23G>A in individuals affected with Congenital Myasthenic Syndrome 18 and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 1360397). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Congenital myasthenic syndrome 18

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 22, 2023

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 8 of the SNAP25 protein (p.Arg8His). 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 variant has not been reported in the literature in individuals affected with SNAP25-related conditions. ClinVar contains an entry for this variant (Variation ID: 1360397). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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

AlphaMissense

Pathogenic

0.58

BayesDel_addAF

Uncertain

0.071

BayesDel_noAF

Benign

-0.14

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.60

D;.;.

Eigen

Pathogenic

0.85

Eigen_PC

Pathogenic

0.87

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Pathogenic

0.98

D;D;D

M_CAP

Benign

0.0087

MetaRNN

Benign

0.42

T;T;T

MetaSVM

Benign

-0.35

MutationAssessor

Benign

2.0

M;M;.

MutationTaster

Benign

1.0

D;D

PrimateAI

Pathogenic

0.91

PROVEAN

Uncertain

-2.5

N;N;D

REVEL

Benign

0.24

Sift

Uncertain

0.018

D;D;D

Sift4G

Benign

0.073

T;T;D

Polyphen

1.0

D;D;.

Vest4

0.71

MVP

0.33

MPC

0.51

ClinPred

0.79

GERP RS

6.1

Varity_R

0.80

gMVP

0.82

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