Several studies have found rare variants in the SYNGAP1 gene to be associated with autism as well as intellectual disability and epilepsy (PMIDs 19196676, 20531469, 21237447, 23020937). Multiple LoF variants (either predicted in silico or demonstrated experimentally) in SYNGAP1 have been identified in patients with ASD and intellectual disability with or without epilepsy (PMIDs 23020937, 23161826, 23708187, 26989088, 27525107, 28554332, 28708303). De novo LoF variants in SYNGAP1 has also been identified in a simplex ASD case from the Simons Simplex Collection (PMID 24267886) and in ASD probands from the Autism Sequencing Consortium (PMID 25363760). Analysis of rare coding variation in 3,871 ASD cases and 9,937 ancestry-matched or paternal controls from the Autism Sequencing Consortium (ASC) in De Rubeis et al., 2014 identified SYNGAP1 as a gene meeting high statistical significance with a FDR 0.01, meaning that this gene had a 99% chance of being a true autism gene (PMID 25363760). This gene was identified in Iossifov et al. 2015 as a strong candidate to be an ASD risk gene based on a combination of de novo mutational evidence and the absence or very low frequency of mutations in controls (PMID 26401017). Additional de novo LoF variants in SYNGAP1 were identified in an ASD proband from a cohort of 200 Canadian ASD trio families in PMID 27525107 and in an ASD proband from the Autism Clinical and Genetic Resources in China (ACGC) cohort in PMID 27824329. A two-stage analysis of rare de novo and inherited coding variants in 42,607 ASD cases, including 35,130 new cases from the SPARK cohort, in Zhou et al., 2022 identified SYNGAP1 as a gene reaching exome-wide significance (P < 2.5E-06).
Molecular Function
A major component of the postsynaptic density (PSD)associated with NMDA receptors
External Links
References
Type
Title
Type of Disorder
Associated Disorders
Author, Year
Primary
De novo SYNGAP1 mutations in nonsyndromic intellectual disability and autism.
Knockdown of syngap1b causes delayed mid- and hindbrain development, disruptions in motor behaviors that manifest as unproductive swim attempts, and spontaneous, seizure-like behaviors indicating syngap1b plays novel roles in morphogenesis resulting in common brain and behavioral phenotypes.
References
Type
Title
Author, Year
Primary
Two knockdown models of the autism genes SYNGAP1 and SHANK3 in zebrafish produce similar behavioral phenotypes associated with embryonic disruption...
Model Type:
Genetic
Model Genotype:
Other
Mutation:
Splice-inhibiting morpholino oligonucleotides (MO) designed for syngap1b were injected into one-cell zygotes of transgenic lines Tg vglut2:dsRed and Tg SaigFF213A. Vglut2 marks excitatory neurons, SaigFF213A marks Caudal Primary (CaP) motor neurons and Rohon-Beard (Rb) sensory neurons. The syngap1b morpholino(MO) targets the intron 3/exon 4 splice-junction and produced one smaller MO- specific band due to exon skipping. syngap1b MOs would be predicted to truncate the corresponding syngap1 protein in the pleckstrin homology domain.
Allele Type: Targeted
Strain of Origin: Tg vglut2:dsRed or Tg SaigFF213A transgenic report
Genetic Background: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line
ES Cell Line: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line embryos
Mutant ES Cell Line: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line embryos
Model Source: Unreported
Model Type:
Genetic
Model Genotype:
Other
Mutation:
Splice-inhibiting morpholino oligonucleotides (MO) designed for syngap1b were injected into one-cell zygotes of transgenic lines Tg vglut2:dsRed and Tg SaigFF213A. Vglut2 marks excitatory neurons, SaigFF213A marks Caudal Primary (CaP) motor neurons and Rohon-Beard (Rb) sensory neurons. The syngap1b morpholino(MO) targets the intron 3/exon 4 splice-junction and produced one smaller MO- specific band due to exon skipping. syngap1b MOs would be predicted to truncate the corresponding syngap1 protein in the pleckstrin homology domain.
Allele Type: Targeted
Strain of Origin: Tg vglut2:dsRed or Tg SaigFF213A transgenic report
Genetic Background: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line
ES Cell Line: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line embryos
Mutant ES Cell Line: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line embryos
Model Source: Unreported
Model Type:
Genetic
Model Genotype:
Other
Mutation:
Splice-inhibiting morpholino oligonucleotides (MO) designed for syngap1b were injected into one-cell zygotes of transgenic lines Tg vglut2:dsRed and Tg SaigFF213A. Vglut2 marks excitatory neurons, SaigFF213A marks Caudal Primary (CaP) motor neurons and Rohon-Beard (Rb) sensory neurons. The syngap1b morpholino(MO) targets the intron 3/exon 4 splice-junction and produced one smaller MO- specific band due to exon skipping. syngap1b MOs would be predicted to truncate the corresponding syngap1 protein in the pleckstrin homology domain.
Allele Type: Targeted
Strain of Origin: Tg vglut2:dsRed or Tg SaigFF213A transgenic report
Genetic Background: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line
ES Cell Line: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line embryos
Mutant ES Cell Line: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line embryos
Model Source: Unreported
Model Type:
Genetic
Model Genotype:
Other
Mutation:
Splice-inhibiting morpholinos for syngap1b and shank3a designed at the the intron3/exon4 boundary for syngap1b and at the intron8/exon8 boundary for shank3a were coinjected at doses that failed to cause phenotypes when singly injected to explore the possibility of synergy. 5ng syngap1b and 4ng shank3a morpholinos was injected.
Allele Type: Targeted
Strain of Origin: Tg vglut2:dsRed or Tg SaigFF213A transgenic report
Genetic Background: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line
ES Cell Line: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line embryos
Mutant ES Cell Line: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line embryos
Model Source: Unreported
Model Type:
Genetic
Model Genotype:
Other
Mutation:
Splice-inhibiting morpholinos for syngap1b and shank3b designed at the intron3/exon4 boundary for syngap1b and at the intron10/exon10 boundary for shank3b were coinjected at doses that failed to cause phenotypes when singly injected to explore the possibility of synergy. 5ng syngap1b and 10ng shank3b morpholinos was injected.
Allele Type: Targeted
Strain of Origin: Tg vglut2:dsRed or Tg SaigFF213A transgenic report
Genetic Background: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line
ES Cell Line: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line embryos
Mutant ES Cell Line: Tg vglut2:dsRed or Tg SaigFF213A transgenic reporter line embryos
Model Source: Unreported
Description: Morphants show unproductive swim attempts compared to controls. Phenotype was most penetrant at 48-72 hpf.
Exp Paradigm: The number of unproductive swim bouts was measured.
Description: syngap1b MO injected zebrafish showed changes in ventricle size and disruptions of the mid-hindbrain boundary compared to uninjected controls
Exp Paradigm: Indentations in at the mid and hind brain boundary were noted
Description: syngap1b MO injected zebrafish showed reduction of GABAergic neurons in the mid- and hindbrain compared to uninjected controls
Exp Paradigm: GABAergic neurons counted
Description: syngap1b MO injected zebrafish showed increased cell death in all brain regions compared to controls, cell death was not rescued with coinjection of p53 MO precluding off-targeting effects
Exp Paradigm: Acridine orange marked cells were counted
Description: syngap1b MO injected zebrafish showed developmental delay of the mid- and hindbrain regions compared to uninjected controls, at 4852 hpf morphant heads were still curved around the yolk as would be stage-appropriate for 2428 hpf. syngap1b MO injected zebrafish showed malformed mid and hindbrains compared to uninjected controls.
Exp Paradigm: Changes in ventricle size and disruptions of the mid-hindbrain boundary were noted
Description: syngap1b MO injected zebrafish showed cardiac edema not seen in controls
Exp Paradigm: Bulbous liquid filled sac adjacent to the pericardium was noted.
Description: syngap1b MO injected zebrafish showed unproductive escape responses characterized by undulations with constant rather than graded frequencies and sustained amplitudes together with an inverted transition from low to high amplitude bends, reduced swimming velocities and increased swimming-bout durations, compared to uninjected controls
Exp Paradigm: Duration of swimming bouts, escape from stimulus, and swimming characteristics were recorded
Description: syngap1b MO injected zebrafish showed syngap1b expression was reduced compared to uninjected controls
Exp Paradigm: To test gene knockdown efficacy MO targeted genes were amplified and a loading control, elongation factor 1, was used-Semi-quantitative PCR (qRT-PCR)
Description: syngap1b MO injected zebrafish showed syngap1b expression was reduced compared to uninjected controls
Exp Paradigm: To test gene knockdown efficacy MO targeted genes were amplified and a loading control, elongation factor 1, was used- In situ hybridization (ISH)
Description: Morphants show decreased syngap1b transcript and produced one smaller MO-specific band due to exon skipping compared to controls.
Exp Paradigm: Loading control used is elongation factor 1alpha.
Description: syngap1b and shank3a MO injected zebrafish showed reduction of GABAergic neurons in the mid- and hindbrain compared to uninjected controls
Exp Paradigm: GABAergic neurons counted
Description: syngap1b and shank3a MO injected zebrafish showed reduced vGlut excitatory neurons in the hindbrain compared to controls
Exp Paradigm: vGlut neurons counted
Description: syngap1b and shank3a MO injected zebrafish showed changes in ventricle size and disruptions of the mid-hindbrain boundary compared to uninjected controls
Exp Paradigm: Indentations in at the mid and hind brain boundary were noted
Description: syngap1b and shank3a MO injected zebrafish showed developmental delay of the mid- and hindbrain regions compared to uninjected controls; at 4852 hpf morphant heads were still curved around the yolk as would be stage-appropriate for 2428 hpf. syngap1b and shank3a MO injected zebrafish showed malformed mid and hindbrains compared to uninjected controls.
Exp Paradigm: Changes in ventricle size and disruptions of the mid-hindbrain boundary were noted.
Description: Some syngap1b MO injected zebrafish showed spontaneous seizures compared to controls
Exp Paradigm: Spontaneous (occurring in the absence of a touch stimulus) seizure-like behaviors characterized by prolonged (lasting seconds to minutes rather than the typical <500 ms) unproductive swim bouts were recorded.
Description: syngap1b and shank3a MO injected zebrafish showed increased cell death in the brain compared to controls
Exp Paradigm: Acridine orange marked cells were counted
Description: Co-injection of syngap1b and shank3a morpholinos showed cardiac edema compared to uninjected controls
Exp Paradigm: Bulbous liquid filled sac adjacent to the pericardium was noted
Description: syngap1b MO injected zebrafish showed unproductive escape responses characterized by undulations with constant rather than graded frequencies and sustained amplitudes together with an inverted transition from low to high amplitude bends, reduced swimming velocities and increased swimming-bout durations, compared to uninjected controls
Exp Paradigm: Duration of swimming bouts, escape from mechanical stimulus, and swimming characteristics were recorded
Description: syngap1b and shank3a MO injected zebrafish showed syngap1b and shank3a transcript expression was reduced compared to uninjected controls
Exp Paradigm: To test gene knockdown efficacy MO targeted genes were amplified and a loading control, elongation factor 1, was used-Semi-quantitative PCR (qRT-PCR)
Description: syngap1b and shank3a MO injected zebrafish showed syngap1b and shank3a transcript expression was reduced compared to uninjected controls
Exp Paradigm: To test gene knockdown efficacy MO targeted genes were amplified and a loading control, elongation factor 1, was used- In situ hybridization (ISH)