NM_006772.3:c.707C>A

Variant names:

• chr6-33435558-C-A
• rs1166557922
• NM_006772.3:c.707C>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_006772.3(SYNGAP1):​c.707C>A​(p.Ala236Glu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,880 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A236V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: SYNGAP1 NM_006772.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 7.91
• 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.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.875

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SYNGAP1	NM_006772.3	c.707C>A	p.Ala236Glu	missense_variant	Exon 7 of 19	ENST00000646630.1	NP_006763.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SYNGAP1	ENST00000646630.1	c.707C>A	p.Ala236Glu	missense_variant	Exon 7 of 19		NM_006772.3	ENSP00000496007.1
SYNGAP1	ENST00000644458.1	c.707C>A	p.Ala236Glu	missense_variant	Exon 7 of 19			ENSP00000495541.1
SYNGAP1	ENST00000449372.7	c.707C>A	p.Ala236Glu	missense_variant	Exon 7 of 18	5		ENSP00000416519.4
SYNGAP1	ENST00000418600.7	c.707C>A	p.Ala236Glu	missense_variant	Exon 7 of 19	5		ENSP00000403636.3
SYNGAP1	ENST00000645250.1	c.530C>A	p.Ala177Glu	missense_variant	Exon 5 of 17			ENSP00000494861.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461880 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727240

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: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1112008

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

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.83
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.62	D;D;.;.;.;.;.;.
Eigen	Pathogenic	0.78
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	.;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.51	D
MetaRNN	Pathogenic	0.87	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.87	D
MutationAssessor	Uncertain	2.7	M;M;.;.;M;M;.;.
PhyloP100		7.9
PrimateAI	Pathogenic	0.87	D
PROVEAN	Uncertain	-4.2	.;.;.;D;.;D;D;.
REVEL	Pathogenic	0.84
Sift	Uncertain	0.0060	.;.;.;D;.;D;D;.
Sift4G	Pathogenic	0.0010	.;D;.;D;D;D;D;.
Polyphen		1.0	D;D;.;D;D;.;.;.
Vest4		0.66, 0.79, 0.62, 0.82
MutPred		0.41		Gain of disorder (P = 0.0399);Gain of disorder (P = 0.0399);Gain of disorder (P = 0.0399);Gain of disorder (P = 0.0399);Gain of disorder (P = 0.0399);Gain of disorder (P = 0.0399);.;.;
MVP		0.95
MPC		2.4
ClinPred		0.99	D
GERP RS		4.6
Varity_R		0.48
gMVP		0.94
Mutation Taster		=45/55	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: rs1166557922; hg19: chr6-33403335;