Figure 5. Decrease in SYNGAP1 levels lead to asynchronous cortical neurogenesis.

A. SOX2 expression in 2 month old Patient^Corrected and Patient^p.Q503X organoids.

B. NeuN expression in 2 month old Patient^Corrected and Patient^p.Q503X organoids.

C. Quantification of the total number of SOX2⁺ cells normalized to DAPI in Patient^Corrected and Patient^p.Q503X organoids. Each dot represents an average value for n= 10 organoids from 1 differentiation. Two-tailed t-test on n=4 differentiations. P v alue =0.0032. Data represented as mean ± SD.

D. Quantification of the total number of NeuN⁺ cells normalized to DAPI in Patient^Corrected and Patient^p.Q503X organoids. Each dot represents an average value for n= 10 organoids from 1 differentiation. T wo-tailed t -test on n=4differentiations. P value =0.0184. Data shown as mean ± SD.

E. SOX2 expression in SYNGAP1 Wild Type (WT), Heterozygous (Het) and KnockOut (KO) E18.5 mice.

F. NEUN expression in SYNGAP1 Wild Type (WT), Heterozygous (Het) and Knock Out (KO) E18.5 mice.

G. Quantification of SOX2 thickness lining the ventricular zone of E18.5 mouse brain lateral ventricles. One Way ANOVA performed on WT= 9, HET= 12, KO =11 ventricles . P value <0.0001. Data shown as mean ± SD.

H. Quantification of NeuN cortical plate thickness in E18.5 mouse brains sections. One Way ANOVA on WT=8, HET= 8, KO =8 ventricles . WT vs Het P value =0.0311, WT vs KO P value <0.0001, Het vs KO P value <0.0001. Data shown as mean ± SD

I. Quantification of the number of SOX2⁺ cells in 100 um² of the VZ area. One Way ANOVA on 6 ventricles from four animals for each genotype. P value=ns. Data shown as mean ± SD.

J. Quantification of the number of NeuN⁺ cells in 100 um² of the VZ area. One Way ANOVA on 6 ventricles from four animals for each genotype. P value =ns. Data shown as mean ± SD.