Table 1 iPSC-based models of ASD discussed in this review

ATRX, AFF2, KCNQ2, SCN2A, and ASTN2

Homozygous deletion

Reduced synaptic activity

CACNA1C

ASD-related mutations

Disrupted interneurons migration

CNTN5 and EHMT2⁺

Heterozygous deletion

Hyperexcitability.

CNTNAP2

Heterozygous deletion

Increased neuronal network activity

FMR1

Heterozygous deletion

Impaired retinoic acid (RA)-dependent homeostatic synaptic plasticity

MECP2

Heterozygous deletion or duplication

Altered synaptic density, altered calcium signaling; altered neuronal firing rate and synchronization; delayed GABA switch

NLGN4

Gene overexpression and ASD-related mutations

Increased excitatory synapse density, altered synaptic strength

NRXN1α

Homozygous and heterozygous deletion, ASD-related mutations

Impaired synaptic strength, altered synaptic calcium signaling

SHANK2

Heterozygous deletion and ASD-related mutations

Hyperconnectivity, enhanced branching complexity, increased synapse density

SHANK3

Heterozygous deletion and ASD-related mutations

Hypoconnectivity, reduced synaptogenesis, and dendritic arborization; impaired neuronal excitability and excitatory synaptic transmission; impaired HCN channels

TSC1/2

Homozygous and heterozygous deletion

Altered neuronal excitability and activity, altered synchrony (cortical neurons); hypoexcitability (cerebellar Purkinje cells)

Other ASD models

Aberrant neuronal maturation, altered neuronal differentiation and synaptic formation