Mutations in TSC2 cause the autosomal dominant disorder tuberous sclerosis (TSC). About 25% of individuals with TSC have autism and 40%-50% meet diagnostic criteria within the autistic spectrum disorders (Smalley et al., 1998). Schaaf et al., 2011 and Kelleher et al., 2012 identified a number of TSC2 missense variants in ASD probands that were not observed in control populations. Rare de novo and inherited missense variants in TSC2 have been identified in ASD probands from the Simons Simplex Collection (ORoak et al., 2012; Bahl et al., 2013; Iossifov et al., 2014), as well as in ASD probands from the Autism Clinical and Genetic Resources in China (ACGC) cohort (Wang et al., 2016). Targeted gene panel screening of a clinical population of 100 children with ASD from the Connecticut Childrens Medical Center Autism Neurogenetics Program in Kalsner et al., 2016 identified 18 rare TSC2 variants in ASD cases (18.0%) compared to 9.8% in the ExAC database (P = 0.0062); the statistical enrichment of rare TSC2 variants in ASD cases remained significant after multiple comparisons correction. Addtional de novo loss-of-function variants and potentially damaging missense variants in the TSC2 gene were reported in ASD probands from the Autism Sequencing Consortium, the MSSNG cohort, and the SPARK cohort in Zhou et al., 2022; 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 this report identified TSC2 as a gene reaching exome-wide significance (P < 2.5E-06).
Molecular Function
The product of this gene is believed to be a tumor suppressor and is able to stimulate specific GTPases.
Cerebellar demyelination and neurodegeneration associated with mTORC1 hyperactivity may contribute to the developmental onset of autism-like neurobehavioral phenotype in a rat model
Developmental effects of constitutive mTORC1 hyperactivity and environmental enrichment on structural synaptic plasticity and behaviour in a rat model of autism spectrum disorder
Model Type:
Genetic
Model Genotype:
Homozygous
Mutation:
Gene targeted replacement of exon 2 of Tsc2 gene with a neomycin resistance cassette.
Allele Type: Targeted (Knock Out)
Strain of Origin: Not Specified
Genetic Background: C57BL/6J or BALB/cJ
ES Cell Line: J1
Mutant ES Cell Line: Not Specified
Model Source: Not Specified
Model Type:
Genetic
Model Genotype:
Heterozygous
Mutation:
Gene targeted replacement of exon 2 of Tsc2 gene with a neomycin resistance cassette.
Allele Type: Targeted (Knock Out)
Strain of Origin: Not Specified
Genetic Background: 129/SvJae-BALB/cJ or 129/SvJae-C57BL/6J
ES Cell Line: J1
Mutant ES Cell Line: Not Specified
Model Source: Not Specified
Model Type:
Genetic
Model Genotype:
Heterozygous
Mutation:
Gene targeted replacement of exon 2 of Tsc2 gene with a neomycin resistance cassette.
Allele Type: Knockout
Strain of Origin: 129S4/SvJae
Genetic Background: Black Swiss Mice
ES Cell Line: J1
Mutant ES Cell Line: Not Specified
Model Source: David J. Kwiatkowski Lab (PMID 10491404), JAX# 004686
Model Type:
Genetic
Model Genotype:
Homozygous
Mutation:
.
Allele Type: Not Specified
Strain of Origin: Not Specified
Genetic Background: Not Specified
ES Cell Line: Not Specified
Mutant ES Cell Line: Not Specified
Model Source: Not Specified
Model Type:
Genetic
Model Genotype:
Homozygous
Mutation:
Conditional deletion of exons 2-4 of the Tsc2 gene using Gfap-cre, in neurons and glia
Allele Type: Conditional loss-of-function
Strain of Origin: Not specified
Genetic Background: Not specified
ES Cell Line: Not specified
Mutant ES Cell Line: Not Specified
Model Source: Not Specified
Model Type:
Genetic
Model Genotype:
Homozygous
Mutation:
Conditional deletion of exons 2-4 of the Tsc2 gene using L7-cre, in Purkinje cells of the cerebellum
Allele Type: Conditional loss-of-function
Strain of Origin: Not specified
Genetic Background: Not specified
ES Cell Line: Not specified
Mutant ES Cell Line: Not Specified
Model Source: Not Specified
Model Type:
Genetic
Model Genotype:
Heterozygous
Mutation:
Conditional hetereozygous deletion of exons 2-4 of the Tsc2 gene using L7-cre, in Purkinje cells of the cerebellum
Allele Type: Conditional loss-of-function
Strain of Origin: Not specified
Genetic Background: 129X1/SvJ and C57BL/6J
ES Cell Line: Not specified
Mutant ES Cell Line: Not Specified
Model Source: Not Specified
Model Type:
Genetic
Model Genotype:
Heterozygous
Mutation:
Targeted deletion of a fragment from codon 74 in exon 2 to codon 164 in exon 5 of Tsc2 gene.
Allele Type: Targeted (Knock Out)
Strain of Origin: Not specified
Genetic Background: C57BL/6J
ES Cell Line: J1
Mutant ES Cell Line: Not Specified
Model Source: Not Specified
Model Type:
Genetic
Model Genotype:
Double KO (Heterozygous/ Homozygous)
Mutation:
Tsc2 heterozygous mice were bred to Atg7 KO mice lacking Atg7 (macroautophagy deficient mice) specifically in the forebrain excitatory neurons to give rise to Tsc2 het an Atg7 neuronal -null double mutants.
Allele Type: Targeted (Knock out)
Strain of Origin: Genetic Background: C57BL/6J
ES Cell Line: Mutant ES Cell Line: Model Source:
Model Type:
Genetic
Model Genotype:
Heterozygous
Mutation:
Tsc2 heterozygous mice crossed with GFP-LC3 mice to visualize the autophagosome marker protein LC3.
Allele Type: Targeted (Knock out)
Strain of Origin: Genetic Background: C57BL/6J
ES Cell Line: Mutant ES Cell Line: Model Source:
Model Type:
Genetic
Model Genotype:
Heterozygous
Mutation:
Mice harborning a neo cassette in the second exon of the Tsc2 gene on chromosome 17.
Allele Type: Knockout
Strain of Origin: 129S4/SvJae
Genetic Background: 129S*C57BL/6J
ES Cell Line: J1
Mutant ES Cell Line: Model Source: David J. Kwiatkowski Lab (PMID 10491404), JAX# 004686
Model Type:
Genetic
Model Genotype:
Heterozygous
Mutation:
Mice harborning a neo cassette in the second exon of the tsc2 gene for rescue experiments vehicle -treated with vehicle (2% dmso, 30% peg400, 5% tween80) from p21 to p28
Allele Type: Knockout
Strain of Origin: 129S4/SvJae
Genetic Background: C57BL/6J
ES Cell Line: J1
Mutant ES Cell Line: Model Source: David J. Kwiatkowski Lab (PMID 10491404), JAX# 004686
Model Type:
Multifactorial
Model Genotype:
Heterozygous
Mutation:
Gene targeted replacement of exon 2 of Tsc2 gene with a neomycin resistance cassette, polyinosinic:polycytidylic acid (poly I:C) injection at P3, P7, and P14.
Allele Type: knockout
Strain of Origin: 129S4/SvJae
Genetic Background: C57Bl/6J
ES Cell Line: J1
Mutant ES Cell Line: Model Source: David J. Kwiatkowski Lab (PMID 10491404), JAX# 004686
Model Type:
Genetic
Model Genotype:
Heterozygous
Mutation:
Heterozygous Tsc1 mice (M_TSC1_7_KO_HT) and heterozygous Tsc2 mice (M_TSC2_8_KO_HT) were crossed to produce double heterozygous mutant mice (Tsc1^+/-;Tsc2^+/-).
Allele Type: Knockout
Strain of Origin: Genetic Background: C57BL/6J
ES Cell Line: Not Specified
Mutant ES Cell Line: Model Source: Not Specified
Description: Delayed growth by 1-2 embryonic days; pale skin and edematous gross appearance; pericardial effusions; exencephaly
Exp Paradigm: General observations
Description: Abnormal general characteristics - hypoplastic liver, poor development of othre abdominal organs, absence of diaphragm, dilated v ascular channels of liver and other abdominal organs
Exp Paradigm: Histological analysis of embryos
Description: Abnormal developmental trajectory - development of several tumor types: renal cysts, liver hemangiomas, lung tumors, and angiosarcomas
Exp Paradigm: Histological analysis of embryos
Description: Abnormal developmental trajectory - renal cysts and adenomas greater than 1-10 mm2 size with dense cellular architecture and large solid adenomatous lesions in kidney
Exp Paradigm: Histological analysis of kidney
Description: Increased levels of anxiety as demonstrated by significantly less time spent in open arms of elevated plus maze
Exp Paradigm: Elevated plus maze test
Description: Abnormal morphology demonstrated by increased astrocyte number in neocortex and hippocampus
Exp Paradigm: Histological analysis of neocortex and hippocampus
Description: Abnormal morphology demonstrated by progressive neuronal disorganization in hippocampus with a dispersion of the pyramidal cell layer
Exp Paradigm: Histological analysis of hippocampus
Description: Increased incidence of observable seizures characterized by head nodding, rearing up on hindlimbs, repetitive forelimb clonus, loss of upright posture
Exp Paradigm: Video-eeg recordings
Description: Decreased social novelty indicated by non-significant preference for novel mouse
Exp Paradigm: Male mice: three chambered apparatus for social novelty
Description: Decreased sociaiblity indicated by no preference shown for chamber with stranger mouse or inanimate object
Exp Paradigm: Female mice: three chambered apparatus for sociability
Description: Tsc2 het mice, after 3 weeks of age -the time period of spinal pruning, show increased number of spines in pyramidal neurons of layer v of the auditory cortex and the secondary somatosensory cortex. compared to wild type (26% reduction in spines) the tsc2 hets only show a reduction of spines or pruning by 3% ( these numbers are from control mice injected with dmso)
Exp Paradigm: NA
Description: Tsc2 het mice have reduced macroautophagy in the cortex, due to increase in mtor activation. macroautophagy was monitored using the level of protein lc3 known to be associated with autophagosomes.
Exp Paradigm: NA
Description: Tsc2 mutant mice exhibited a decrease in the amount of time spent interacting with a wildtype mate of the same sex compared to wildtype controls.
Description: Tsc2 het mice had a lower preference index towards the social target compared to a non social target compared to controls. tsc2 do spend more type with the social target compared to non social target, but the preference index is smaller than controls
Exp Paradigm: NA
Description: Tsc2 mutant mice exhibited impaired social memory compared to control mice, spending comparable amounts of time exploring the novel versus familiar cagemate mouse, whereas wildtype mice spent significantly more time exploring the novel mouse. This was further validated by a significant reduction in the approach-avoidance score ((time exploring S3) â?? (time exploring C)) compared to both Tsc1 and wildtype mice.
Exp Paradigm: Novel mouse: stranger (S3); Familiar mouse: cagemate
Description: Tsc2 mutant mice exhibited impaired social memory compared to control mice, spending comparable amounts of time exploring the novel versus familiar (non-cagemate) mouse, whereas wildtype mice spent significantly more time exploring the novel mouse.
Exp Paradigm: Novel mouse: stranger (S2); Familiar mouse: non-cagemate previously introduced for 10 mins (S1).
Description: Decreased social interaction demonstrated by shorter time engaged in active exploration i.e. exploring a novel mouse
Exp Paradigm: Social interaction test with novel mouse scored for sniffing, allo-grooming, mounting, and following
Description: Tsc2 het mice had a lower preference index, spend similar amount of time sniffing, the new social target compared to a familiar social target compared to controls.
Exp Paradigm: NA
Description: By p29 the double knock out mice for tsc2 (het) atg (null) show increased number of spines as a result of lack of spinal pruning that reduces the number of spines by 26% in wild type mice between p20 and p28. in the double knock out there is only a reduction by 2%
Exp Paradigm: NA
Description: The double knock out tsc2 het/ atg null mice show impaired social preference in the three chamber test, towards the new social target compared to the familiar social target
Exp Paradigm: NA
Description: The double knock out tsc2 het/ atg null mice show impaired social preference or sociability in the three chamber test, towards the social target compared to the non social target
Exp Paradigm: NA
Description: Tsc2 het mice with gfp tagged lc3 protein show reduced levels of the labeled lc3 puncta confirming a reductionin autophagosome formation and macroautophagy in the cortical pyramidal neurons
Exp Paradigm: NA
Description: Tsc2 het mice with gfp tagged lc3 protein have increased levels of phospho s6, indicating increased mtor activation, in cortical pyramidal neurons
Exp Paradigm: NA
Spontaneous post synaptic event frequency: excitatory currents1
Decreased
Description: Mutants show reduced spontaneous mepsc frequency in l2/l3 pyramidal neurons of the s1 somatosensory cortex compared with controls.
Exp Paradigm: S1 somatosensory cortex; acute slices; l2/3 pyramidal neurons
Description: Mutants show no change in peak amplitude of postsynaptic potential but show an increase in the number of spikes following a train of l4 stimulation compared with controls indicating no change in temporal summation.
Exp Paradigm: L4 train-evoked postsynaptic potentials and spikes in l2/3 pyramidal cells (5 pulses at 20 hz).
Spontaneous post synaptic event amplitude: excitatory currents1
Decreased
Description: Mutants show reduction in spontaneous mepsc amplitude in l2/l3 pyramidal neurons of the s1 somatosensory cortex compared with controls.
Exp Paradigm: S1 somatosensory cortex; acute slices; l2/3 pyramidal neurons
Description: Mutants show decrease in ipscs compared with controls.
Exp Paradigm: L4-evoked feedforward excitatory and inhibitory currents converging onto single l2/3 pyramidal cells were measured in the s1 somatosensory cortex in acute slices. epsc amplitudes were compared at the minimum l4 stimulation intensity required to evoke a detectable epsc and at peak current amplitude.
Description: Mutants show no change in specific membrane capacitance (cm), membrane time constant (tao-mem),spike threshold and rheobase but a decrease in input resistance (ri) compared with controls.
Exp Paradigm: S1 somatosensory cortex; acute slices
Spontaneous post synaptic event frequency: inhibitory currents1
Decreased
Description: Mutants show decrease in spontaneous mipsc frequency in l2/l3 pyramidal neurons of the s1 somatosensory cortex compared with controls.
Exp Paradigm: S1 somatosensory cortex; acute slices; l2/3 pyramidal neurons
Decay kinetics of miniature post synaptic currents1
Increased
Description: Mutants show increase in duration of l4 evoked post synaptic potential compared with controls.
Exp Paradigm: Single stimulus l4-evoked post-synaptic potentials recorded in l2/3 pyramidal neurons at 1.4 times the minimum l4 stimulation intensity required to evoke a detectable epsc (e-theta), with nmda currents intact.
Description: Mutants show increase in e-i conductance ratio compared with controls.
Exp Paradigm: L4-evoked feedforward excitatory and inhibitory currents converging onto single l2/3 pyramidal cells were measured in the s1 somatosensory cortex in acute slices. epsc amplitudes were compared at the minimum l4 stimulation intensity required to evoke a detectable epsc and at peak current amplitude.
Functional magnetic resonance imaging: connectivity2
increased
Description: Global connectivity analysis revealed prominent foci of increased connectivity in the pfc and insular cortex of tsc2+/- mice; seed based mapping revealed that tsc2+/- mice exhibit functional over-synchronization between the prefrontal cortex and the posterior cingulate, anterior insula, and corticalâ??striatal components of the dmn; similarly, the anterior insula was oversynchronized with prefrontal regions and the retrosplenial cortex
Functional magnetic resonance imaging (FMRI)-resting state
Description: Tsc2+/â?? mutants exhibited increased stereotypical grooming behavior; fronto striatalâ??cortical hyperconnectivity was prominently associated with repetitive motor behavior
Description: Tsc2+/â?? mutants exhibited significantly decreased social investigation; analysis did not reveal any significant correlation between social scores and rsfmri hyperconnectivity
Description: Tsc2 heterozygous pups exhibit an increase in the amount of short calls, chevron, and complex call types. A decrease in two-syllable calling is also observed.
Description: Male Tsc2 heterozygous mice injected with poly I:C early postnatally show social memory deficits; sexual dimorphism. Unlike early postnatal injections, adult poly I:C injections do not trigger chronic deficits in social memory in Tsc2 heterozygous male mice.
Description: Poly I:C-treated (at P3) Tsc2 heterozygous pups, but not their WT littermates, show a call repertoire dominated by the short call type and exhibit a significant increase in calls with an abnormal harmonic structure that does not fit into any predefined call type.
Description: 17 genes exhibit differential expression across prefrontal cortex, hippocampus, and cerebellum regions. Known markers of microglia were significantly enriched among up-regulated genes.
Description: TscD mutant mice exhibited impaired social memory compared to control mice, spending comparable amounts of time exploring the novel versus familiar (non-cagemate) mouse, whereas wildtype mice spent significantly more time exploring the novel mouse.
Exp Paradigm: Novel mouse: stranger (S2); Familiar mouse: non-cagemate previously introduced for 10 mins (S1).
Description: TscD mutant mice exhibited a decrease in the amount of time spent interacting with a wildtype mate of the same sex compared to wildtype controls.
Description: TscD mutant mice exhibited impaired social memory compared to control mice, spending comparable amounts of time exploring the novel versus familiar cagemate mouse, whereas wildtype mice spent significantly more time exploring the novel mouse. This was further validated by a significant reduction in the approach-avoidance score ((time exploring S3) â?? (time exploring C)) compared to both Tsc1 and wildtype mice.
Exp Paradigm: Novel mouse: stranger (S3); Familiar mouse: cagemate