rs1554120589

Variant names:

• chr6-33432781-C-G
• rs1554120589
• NM_006772.3:c.484C>G

Your query was ambiguous. Multiple possible variants found:

• chr6-33432781-C-G
• chr6-33432781-C-T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 6P and 2B. PM1 PM2 PM5 BP4_Moderate

The NM_006772.3(SYNGAP1):​c.484C>G​(p.Arg162Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 13/22 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. R162H) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 31)
• Consequence: SYNGAP1 NM_006772.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.669
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• complex neurodevelopmental disorder

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• intellectual disability, autosomal dominant 5

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• autosomal dominant non-syndromic intellectual disability

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• SYNGAP1-related developmental and epileptic encephalopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• myoclonic-astatic epilepsy

  Inheritance: Unknown Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 5 uncertain in NM_006772.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr6-33432781-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 438306.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP4: Computational evidence support a benign effect (MetaRNN=0.12284672).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SYNGAP1	NM_006772.3	c.484C>G	p.Arg162Gly	missense_variant	Exon 5 of 19	ENST00000646630.1	NP_006763.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SYNGAP1	ENST00000646630.1	c.484C>G	p.Arg162Gly	missense_variant	Exon 5 of 19		NM_006772.3	ENSP00000496007.1
SYNGAP1	ENST00000644458.1	c.484C>G	p.Arg162Gly	missense_variant	Exon 5 of 19			ENSP00000495541.1
SYNGAP1	ENST00000449372.7	c.484C>G	p.Arg162Gly	missense_variant	Exon 5 of 18	5		ENSP00000416519.4
SYNGAP1	ENST00000418600.7	c.484C>G	p.Arg162Gly	missense_variant	Exon 5 of 19	5		ENSP00000403636.3
SYNGAP1	ENST00000645250.1	c.307C>G	p.Arg103Gly	missense_variant	Exon 3 of 17			ENSP00000494861.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 37

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Intellectual disability, autosomal dominant 5 Uncertain:1

Sep 06, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 162 of the SYNGAP1 protein (p.Arg162Gly). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SYNGAP1-related conditions. Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt SYNGAP1 protein function with a negative predictive value of 95%. 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	0.66
BayesDel_addAF	Benign	-0.047	T
BayesDel_noAF	Benign	-0.31
CADD	Uncertain	24
DANN	Benign	0.94
DEOGEN2	Benign	0.047	T;T;.;.;.;.;.;.
Eigen	Benign	-0.45
Eigen_PC	Benign	-0.26
FATHMM_MKL	Uncertain	0.78	D
LIST_S2	Benign	0.69	.;T;T;T;T;T;T;T
M_CAP	Benign	0.012	T
MetaRNN	Benign	0.12	T;T;T;T;T;T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	-0.69	N;N;.;.;N;N;.;.
PhyloP100		0.67
PrimateAI	Pathogenic	0.86	D
PROVEAN	Benign	-0.69	.;.;.;N;.;N;N;.
REVEL	Benign	0.19
Sift	Benign	0.56	.;.;.;T;.;T;T;.
Sift4G	Benign	0.58	.;T;.;T;T;T;T;.
Polyphen		0.49	P;P;.;B;P;.;.;.
Vest4		0.31, 0.27, 0.45, 0.41
MutPred		0.30		Loss of MoRF binding (P = 0.0304);Loss of MoRF binding (P = 0.0304);Loss of MoRF binding (P = 0.0304);Loss of MoRF binding (P = 0.0304);Loss of MoRF binding (P = 0.0304);Loss of MoRF binding (P = 0.0304);.;.;
MVP		0.70
MPC		1.9
ClinPred		0.34	T
GERP RS		3.5
Varity_R		0.23
gMVP		0.92
Mutation Taster		=22/78	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs1554120589; hg19: chr6-33400558;