6-33438873-C-T
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Variant summary
Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong
The NM_006772.3(SYNGAP1):c.1630C>T(p.Arg544Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.
Frequency
Genomes: not found (cov: 32)
Consequence
SYNGAP1
NM_006772.3 stop_gained
NM_006772.3 stop_gained
Scores
2
3
2
Clinical Significance
Conservation
PhyloP100: 0.591
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]
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ACMG classification
Classification made for transcript
Verdict is Pathogenic. Variant got 18 ACMG points.
PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 6-33438873-C-T is Pathogenic according to our data. Variant chr6-33438873-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 522845.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | UniProt |
---|---|---|---|---|---|---|---|
SYNGAP1 | NM_006772.3 | c.1630C>T | p.Arg544Ter | stop_gained | 10/19 | ENST00000646630.1 | |
SYNGAP1-AS1 | NR_174954.1 | n.330-1392G>A | intron_variant, non_coding_transcript_variant |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|
SYNGAP1 | ENST00000646630.1 | c.1630C>T | p.Arg544Ter | stop_gained | 10/19 | NM_006772.3 | P1 | ||
SYNGAP1-AS1 | ENST00000630418.1 | n.378-1392G>A | intron_variant, non_coding_transcript_variant | 5 |
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD3 genomes
Cov.:
32
GnomAD4 exome Cov.: 34
GnomAD4 exome
Cov.:
34
GnomAD4 genome Cov.: 32
GnomAD4 genome
Cov.:
32
ClinVar
Significance: Pathogenic
Submissions summary: Pathogenic:7
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
Intellectual disability, autosomal dominant 5 Pathogenic:4
Pathogenic, criteria provided, single submitter | clinical testing | Invitae | Jul 01, 2022 | For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 522845). This premature translational stop signal has been observed in individual(s) with infantile epileptic encephalopathy (PMID: 26989088). In at least one individual the variant was observed to be de novo. This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Arg544*) in the SYNGAP1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in SYNGAP1 are known to be pathogenic (PMID: 23161826, 23708187, 26989088). - |
Pathogenic, criteria provided, single submitter | clinical testing | Undiagnosed Diseases Network, NIH | Jun 16, 2017 | A mosaic c.1630C>T (p.R544X) pathogenic variant in the SYNGAP1 gene was detected in this individual (33 mutant and 256 reference reads) and was confirmed by Sanger sequencing. This variant has been previously reported as de novo in a patient with intellectual disability and developmental delay (PMID: 26989088) and is predicted to result in a premature stop codon. - |
Pathogenic, criteria provided, single submitter | clinical testing | Rady Children's Institute for Genomic Medicine, Rady Children's Hospital San Diego | Dec 04, 2018 | This nonsense variant found in exon 10 of 19 is predicted to result in loss of normal protein function. This variant has been previously reported as a de novo change in a patient with global developmental delay and epilepsy (PMID: 26989088). It is absent from the ExAC and gnomAD population databases and thus is presumed to be rare. Based on the available evidence, the c.1630C>T (p.Arg544Ter) variant is classified as pathogenic. - |
Pathogenic, criteria provided, single submitter | clinical testing | Baylor Genetics | Sep 01, 2017 | This nonsense variant is categorized as deleterious according to ACMG guidelines (PMID:18414213) and was found once in our laboratory de novo in an 11-year-old female with Leigh disease, intellectual disability, short stature, microcephaly, failure to thrive, PDA, brachydactyly, pes planus, congenital hypothyroidism. Patient also carried compound heterozygous pathogenic variants in MTFMT. - |
not provided Pathogenic:2
Pathogenic, criteria provided, single submitter | clinical testing | CeGaT Center for Human Genetics Tuebingen | Jan 01, 2020 | - - |
Pathogenic, criteria provided, single submitter | clinical testing | GeneDx | Oct 31, 2023 | Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 31349857, 25326635, 26989088) - |
Inborn genetic diseases Pathogenic:1
Pathogenic, criteria provided, single submitter | clinical testing | Ambry Genetics | Aug 26, 2021 | The c.1630C>T (p.R544*) alteration, located in exon 10 (coding exon 10) of the SYNGAP1 gene, consists of a C to T substitution at nucleotide position 1630. This changes the amino acid from an arginine (R) to a stop codon at amino acid position 544. This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This alteration has been reported to occur de novo in a patient with severe intellectual disability, truncal hypotonia, swallowing difficulties, epilepsy, and very poor social interactions (Mignot, 2016). In addition, this alteration has also been identified in a patient with generalized epilepsy (Hoelz, 2020) and in a mosaic patient with a neurodevelopmental phenotype (Cao, 2019). Based on the available evidence, this alteration is classified as pathogenic. - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Pathogenic
D
BayesDel_noAF
Pathogenic
CADD
Pathogenic
DANN
Uncertain
Eigen
Uncertain
Eigen_PC
Uncertain
FATHMM_MKL
Benign
D
MutationTaster
Benign
A;A;A;A
Vest4
0.93, 0.94, 0.94, 0.93
GERP RS
RBP_binding_hub_radar
RBP_regulation_power_radar
Splicing
Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at