rs1057519546

Variant names:

• chr6-33432806-G-A
• rs1057519546
• NM_006772.3:c.509G>A
• SYNGAP1 p.Arg170Gln

Variant summary

Our verdict is Pathogenic. The variant received 20 ACMG points: 20P and 0B. PS3 PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_006772.3(SYNGAP1):​c.509G>A​(p.Arg170Gln) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV005419410: RNA studies demonstrate a damaging effect: altered splicing with 34 bp insertion of intron 5 that is out-of-frame (PMID:38113761)". Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R170W) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 31)
• Consequence: SYNGAP1 NM_006772.3 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:6
• Conservation: PhyloP100: 9.27
• Publications: 7 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, PanelApp Australia, 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: Pathogenic. The variant received 20 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV005419410: RNA studies demonstrate a damaging effect: altered splicing with 34 bp insertion of intron 5 that is out-of-frame (PMID: 38113761)
• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 8 uncertain in NM_006772.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 6-33432806-G-A is Pathogenic according to our data. Variant chr6-33432806-G-A is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 375528.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SYNGAP1	NM_006772.3	MANE Select	c.509G>A	p.Arg170Gln	missense splice_region	Exon 5 of 19	NP_006763.2	A0A1U9X8L0
	SYNGAP1	NM_001130066.2		c.509G>A	p.Arg170Gln	missense splice_region	Exon 5 of 18	NP_001123538.1	B7ZCA0

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SYNGAP1	ENST00000646630.1	MANE Select	c.509G>A	p.Arg170Gln	missense splice_region	Exon 5 of 19	ENSP00000496007.1	Q96PV0-1
	SYNGAP1	ENST00000644458.1		c.509G>A	p.Arg170Gln	missense splice_region	Exon 5 of 19	ENSP00000495541.1	A0A2R8Y6T2
	SYNGAP1	ENST00000449372.7	TSL:5	c.509G>A	p.Arg170Gln	missense splice_region	Exon 5 of 18	ENSP00000416519.4	B7ZCA0

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 38

GnomAD4 genome Cov.: 31

ClinVar

ClinVar submissions

Significance: Pathogenic/Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
4	-	-	Intellectual disability, autosomal dominant 5 (4)
2	-	-	not provided (2)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.80
BayesDel_addAF	Benign	-0.040	T
BayesDel_noAF	Benign	-0.29
CADD	Pathogenic	36
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.31	T
Eigen	Uncertain	0.59
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Uncertain	0.87	D
M_CAP	Benign	0.030	D
MetaRNN	Benign	0.32	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Uncertain	2.3	M
PhyloP100		9.3
PrimateAI	Uncertain	0.75	T
PROVEAN	Benign	-2.3	N
REVEL	Benign	0.22
Sift	Uncertain	0.0030	D
Sift4G	Uncertain	0.0070	D
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.14
gMVP		0.82
Mutation Taster		=3/97	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.77		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.53		Position offset: 34
DS_DL_spliceai		0.77		Position offset: 0

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs1057519546;

hg19: chr6-33400583;