6-33443148-G-T

Position:

chr6-33443148-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2PP2BP4_Moderate

The NM_006772.3(SYNGAP1):c.2596G>T(p.Val866Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,224 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict 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. V866I) has been classified as Likely benign.

Frequency

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

Consequence

SYNGAP1
NM_006772.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.96

Variant links:

Genes affected

SYNGAP1 (HGNC:11497): (synaptic Ras GTPase activating protein 1) This gene encodes a Ras GTPase activating protein that is a member of the N-methyl-D-aspartate receptor complex. The N-terminal domain of the protein contains a Ras-GAP domain, a pleckstrin homology domain, and a C2 domain that may be involved in binding of calcium and phospholipids. The C-terminal domain consists of a ten histidine repeat region, serine and tyrosine phosphorylation sites, and a T/SXV motif required for postsynaptic scaffold protein interaction. The encoded protein negatively regulates Ras, Rap and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor trafficking to the postsynaptic membrane to regulate synaptic plasticity and neuronal homeostasis. Allelic variants of this gene are associated with intellectual disability and autism spectrum disorder. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2016]

SYNGAP1 links:

SYNGAP1-AS1 (HGNC:53831): (SYNGAP1 antisense RNA 1)

SYNGAP1-AS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant where missense usually causes diseases, SYNGAP1

BP4

Computational evidence support a benign effect (MetaRNN=0.101602554).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SYNGAP1	NM_006772.3 linkuse as main transcript	c.2596G>T	p.Val866Leu	missense_variant	15/19	ENST00000646630.1
SYNGAP1-AS1	NR_174954.1 linkuse as main transcript	n.329+3458C>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SYNGAP1	ENST00000646630.1 linkuse as main transcript	c.2596G>T	p.Val866Leu	missense_variant	15/19		NM_006772.3	P1	Q96PV0-1
SYNGAP1-AS1	ENST00000630418.1 linkuse as main transcript	n.377+3458C>A		intron_variant, non_coding_transcript_variant		5

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152224

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:

0.000193

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:

0.00000800

AC:

AN:

250114

Hom.:

AF XY:

0.0000148

AC XY:

AN XY:

135346

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000109

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

Cov.:

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152224

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74364

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000193

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000378

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Intellectual disability, autosomal dominant 5

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Aug 20, 2021

This sequence change replaces valine with leucine at codon 866 of the SYNGAP1 protein (p.Val866Leu). The valine residue is moderately conserved and there is a small physicochemical difference between valine and leucine. This variant is present in population databases (rs768878991, ExAC 0.01%). This variant has not been reported in the literature in individuals affected with SYNGAP1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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

Benign

0.15

BayesDel_addAF

Benign

-0.31

BayesDel_noAF

Benign

-0.46

CADD

Uncertain

DANN

Uncertain

0.98

DEOGEN2

Benign

0.065

T;T;.;.;.;.;.;.

Eigen

Benign

-0.38

Eigen_PC

Benign

-0.30

FATHMM_MKL

Uncertain

0.93

M_CAP

Benign

0.015

MetaRNN

Benign

0.10

T;T;T;T;T;T;T;T

MetaSVM

Benign

-1.0

MutationAssessor

Benign

1.9

L;L;.;.;L;L;.;.

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Uncertain

0.68

Polyphen

0.22

B;B;.;.;B;B;.;.

Vest4

0.046, 0.054, 0.075, 0.065

MutPred

0.17

Gain of loop (P = 0.0195);Gain of loop (P = 0.0195);Gain of loop (P = 0.0195);.;Gain of loop (P = 0.0195);Gain of loop (P = 0.0195);.;.;

MVP

0.47

MPC

1.4

ClinPred

0.17

GERP RS

3.6

Varity_R

0.070

gMVP

0.62

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