rs748333558

chr6-33438190-C-T

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 1P and 4B. PP2 BS2

The NM_006772.3(SYNGAP1):c.1285C>T(p.Arg429Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000403 in 1,614,096 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R429Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000042 (0 hom.)
• Consequence: SYNGAP1 NM_006772.3 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:1
• Conservation: PhyloP100: 1.74

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

Verdict is Likely_benign. Variant got -3 ACMG points.

• PP2: Missense variant where missense usually causes diseases, SYNGAP1
• BS2: High AC in GnomAdExome at 7 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SYNGAP1	NM_006772.3	c.1285C>T	p.Arg429Trp	missense_variant	8/19	ENST00000646630.1
SYNGAP1-AS1	NR_174954.1	n.330-709G>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SYNGAP1	ENST00000646630.1	c.1285C>T	p.Arg429Trp	missense_variant	8/19		NM_006772.3	P1
SYNGAP1-AS1	ENST00000630418.1	n.378-709G>A		intron_variant, non_coding_transcript_variant		5

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152206 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.0000441

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000281 AC: 7 AN: 249188 Hom.: 0 AF XY: 0.0000148 AC XY: 2 AN XY: 134932

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000462

Gnomad NFE exome AF: 0.0000359

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.0000424 AC: 62 AN: 1461890 Hom.: 0 Cov.: 35 AF XY: 0.0000358 AC XY: 26 AN XY: 727246

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000252

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000187

Gnomad4 NFE exome AF: 0.0000486

Gnomad4 OTH exome AF: 0.0000828

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152206 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74350

Gnomad4 AFR AF: 0.00

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: 0.0000441

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000847 Hom.: 0

Bravo AF: 0.0000227

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Aug 01, 2016	- -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Oct 24, 2023	In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Intellectual disability, autosomal dominant 5 Uncertain:1 Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Invitae	Jun 23, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	New York Genome Center	Feb 26, 2021	The de novo heterozygous missense c.1285C>T (p.Arg429Trp) variant identified in the SYNGAP1 gene of this individual has not been reported in affected individuals in the literature. It has been reported in the ClinVar database as a variant of uncertain significance (2) and likely benign (1) [Variation ID:374457]. The variant has 0.00001971 allele frequency in the gnomAD(v3) database (3 out of 152,206 heterozygous alleles, no homozygotes) suggesting it is not a common benign allele in the populations represented in that database. The affected residue is not well conserved. In silico tools provide conflicting predictions about potential pathogenicity of this variant [CADD score = 25.9, REVEL score =0.282]. Functional studies to evaluate the functional consequences of this variant have not been reported. Given the lack of compelling evidence about its pathogenicity, the de novo heterozygous missense c.1285C>T (p.Arg429Trp) variant identified in the SYNGAP1 gene is reported here as a variant of uncertain significance. -

Global developmental delay Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Claritas Genomics

Feb 21, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.50
BayesDel_addAF	Benign	0.0037	T
BayesDel_noAF	Uncertain	-0.060
Cadd	Pathogenic	34
Dann	Pathogenic	1.0
DEOGEN2	Uncertain	0.65	D;D;.;.;.;.;.;.
Eigen	Uncertain	0.46
Eigen_PC	Uncertain	0.42
FATHMM_MKL	Uncertain	0.93	D
M_CAP	Benign	0.011	T
MetaRNN	Uncertain	0.64	D;D;D;D;D;D;D;D
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.5	L;L;.;.;L;L;.;.
MutationTaster	Benign	1.0	D;D;D;D
PrimateAI	Uncertain	0.75	T
Polyphen		1.0	D;D;.;D;D;D;.;.
Vest4		0.52, 0.51, 0.54, 0.50
MutPred		0.65		Loss of solvent accessibility (P = 0.1077);Loss of solvent accessibility (P = 0.1077);Loss of solvent accessibility (P = 0.1077);Loss of solvent accessibility (P = 0.1077);Loss of solvent accessibility (P = 0.1077);Loss of solvent accessibility (P = 0.1077);.;.;
MVP		0.61
MPC		2.3
ClinPred		0.71	D
GERP RS		4.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.47
gMVP		0.86

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.11		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

Other links and lift over

dbSNP: rs748333558; hg19: chr6-33405967; COSMIC: COSV99537778; COSMIC: COSV99537778;