rs1554122198

Variant names:

• chr6-33443058-A-G
• rs1554122198
• NM_006772.3:c.2506A>G

Variant summary

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

The NM_006772.3(SYNGAP1):​c.2506A>G​(p.Ser836Gly) variant causes a missense change. The variant allele was found at a frequency of 0.00000248 in 1,614,046 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 (★).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 31)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: SYNGAP1 NM_006772.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.84
• 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-AS1 (HGNC:53831): (SYNGAP1 antisense RNA 1)

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 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, 6 uncertain in NM_006772.3
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.16481268).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006772.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SYNGAP1	NM_006772.3	MANE Select	c.2506A>G	p.Ser836Gly	missense	Exon 15 of 19	NP_006763.2
	SYNGAP1	NM_001130066.2		c.2464A>G	p.Ser822Gly	missense	Exon 14 of 18	NP_001123538.1
	SYNGAP1-AS1	NR_174954.1		n.329+3548T>C		intron	N/A

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SYNGAP1	ENST00000646630.1	MANE Select	c.2506A>G	p.Ser836Gly	missense	Exon 15 of 19	ENSP00000496007.1
	SYNGAP1	ENST00000644458.1		c.2506A>G	p.Ser836Gly	missense	Exon 15 of 19	ENSP00000495541.1
	SYNGAP1	ENST00000449372.7	TSL:5	c.2464A>G	p.Ser822Gly	missense	Exon 14 of 18	ENSP00000416519.4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152154 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.0000241

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: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461892 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 727246

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152154 Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1 AN XY: 74326

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.0000241 AC: 1 AN: 41438

American (AMR) AF: 0.00 AC: 0 AN: 15286

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5172

South Asian (SAS) AF: 0.00 AC: 0 AN: 4836

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68024

Other (OTH) AF: 0.00 AC: 0 AN: 2084

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Intellectual disability, autosomal dominant 5 Uncertain:1

Aug 30, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt SYNGAP1 protein function. ClinVar contains an entry for this variant (Variation ID: 537003). This variant has not been reported in the literature in individuals affected with SYNGAP1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces serine, which is neutral and polar, with glycine, which is neutral and non-polar, at codon 836 of the SYNGAP1 protein (p.Ser836Gly).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.42
CADD	Uncertain	24
DANN	Benign	0.92
DEOGEN2	Benign	0.089	T
Eigen	Benign	-0.14
Eigen_PC	Benign	0.038
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.87	D
M_CAP	Benign	0.010	T
MetaRNN	Benign	0.16	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.8	L
PhyloP100		6.8
PrimateAI	Uncertain	0.58	T
PROVEAN	Benign	-1.5	N
REVEL	Benign	0.066
Sift	Benign	0.34	T
Sift4G	Benign	0.55	T
Polyphen		0.0060	B
Vest4		0.19
MutPred		0.22		Loss of phosphorylation at S836 (P = 0.0447)
MVP		0.19
MPC		2.1
ClinPred		0.85	D
GERP RS		4.5
Varity_R		0.25
gMVP		0.21
Mutation Taster		=86/14	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1554122198; hg19: chr6-33410835;