rs755438249

Variant names:

• chr6-33440721-C-A
• rs755438249
• NM_006772.3:c.1677-8C>A

Your query was ambiguous. Multiple possible variants found:

• chr6-33440721-C-A
• chr6-33440721-C-T

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Moderate BP6_Moderate

The NM_006772.3(SYNGAP1):​c.1677-8C>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,138 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★).

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 31)
• Consequence: SYNGAP1 NM_006772.3 splice_region, intron
• Scores: Splicing: ADA: 0.06307
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 0.211
• 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: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.37).
• BP6: Variant 6-33440721-C-A is Benign according to our data. Variant chr6-33440721-C-A is described in ClinVar as Likely_benign. ClinVar VariationId is 2814860.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SYNGAP1	NM_006772.3	c.1677-8C>A		splice_region_variant, intron_variant	Intron 10 of 18	ENST00000646630.1	NP_006763.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SYNGAP1	ENST00000646630.1	c.1677-8C>A		splice_region_variant, intron_variant	Intron 10 of 18		NM_006772.3	ENSP00000496007.1
SYNGAP1	ENST00000644458.1	c.1677-8C>A		splice_region_variant, intron_variant	Intron 10 of 18			ENSP00000495541.1
SYNGAP1	ENST00000449372.7	c.1677-8C>A		splice_region_variant, intron_variant	Intron 10 of 17	5		ENSP00000416519.4
SYNGAP1	ENST00000418600.7	c.1677-8C>A		splice_region_variant, intron_variant	Intron 10 of 18	5		ENSP00000403636.3
SYNGAP1	ENST00000645250.1	c.1500-8C>A		splice_region_variant, intron_variant	Intron 8 of 16			ENSP00000494861.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152138 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.000288

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 Cov.: 33

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152138 Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1 AN XY: 74316

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

African (AFR) AF: 0.00 AC: 0 AN: 41432

American (AMR) AF: 0.00 AC: 0 AN: 15266

Ashkenazi Jewish (ASJ) AF: 0.000288 AC: 1 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10616

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68008

Other (OTH) AF: 0.00 AC: 0 AN: 2090

⚠️ 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.

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Intellectual disability, autosomal dominant 5 Benign:1

Nov 17, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.37
CADD	Benign	12
DANN	Benign	0.93
PhyloP100		0.21
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.2

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.063
dbscSNV1_RF	Benign	0.19
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: rs755438249; hg19: chr6-33408498;