We utilized forebrain organoids generated from induced pluripotent stem cells of patients with a syndromic form of Autism Spectrum Disorder (ASD) with a homozygous protein-truncating mutation in CNTNAP2, to study its effects on embryonic cortical development. Patients with this mutation present with clinical characteristics of brain overgrowth. Patient-derived forebrain organoids displayed an increase in volume and total cell number that is driven by increased neural progenitor proliferation. Single-cell RNA sequencing revealed PFC-excitatory neurons to be the key cell types expressing CNTNAP2. Gene ontology analysis of differentially expressed genes (DEgenes) corroborates aberrant cellular proliferation. Moreover, the DEgenes are enriched for ASD-associated genes. The cell-type-specific signature genes of the CNTNAP2-expressing neurons are associated with clinical phenotypes previously described in patients. The organoid overgrowth phenotypes were largely rescued after correction of the mutation using CRISPR-Cas9. This CNTNAP2-organoid model provides opportunity for further mechanistic inquiry and development of new therapeutic strategies for ASD.

The blood–brain barrier (BBB) is important in the normal functioning of the central nervous system. An altered BBB has been described in various neuropsychiatric disorders, including schizophrenia. However, the cellular and molecular mechanisms of such alterations remain unclear. Here, we investigate if BBB integrity is compromised in 22q11.2 deletion syndrome (also called DiGeorge syndrome), which is one of the validated genetic risk factors for schizophrenia. We utilized a set of human brain microvascular endothelial cells (HBMECs) derived from the induced pluripotent stem cell (iPSC) lines of patients with 22q11.2-deletion-syndrome-associated schizophrenia. We found that the solute permeability of the BBB formed from patient HBMECs increases by ~1.3–1.4-fold, while the trans-endothelial electrical resistance decreases to ~62% of the control values. Correspondingly, tight junction proteins and the endothelial glycocalyx that determine the integrity of the BBB are significantly disrupted. A transcriptome study also suggests that the transcriptional network related to the cell–cell junctions in the compromised BBB is substantially altered. An enrichment analysis further suggests that the genes within the altered gene expression network also contribute to neurodevelopmental disorders. Our findings suggest that neurovascular coupling can be targeted in developing novel therapeutical strategies for the treatment of 22q11.2 deletion syndrome.

Children and adults with 22q11.2 deletion syndrome (22q11.2DS) experience cognitive and emotional challenges and face a markedly increased risk for schizophrenia (SCZ), yet how this deletion alters early human brain development remains unclear. Using cerebral cortex organoids derived from individuals with 22q11.2DS and SCZ, we identify cell-type-specific developmental abnormalities. Single-cell RNA sequencing and experimental validation reveal delayed cortical neuron maturation, with increased neural progenitor proliferation and a reduced proportion of more mature neurons. We observe disrupted molecular programs linked to neuronal maturation, sparser neurites, and blunted glutamate-induced Ca²⁺ responses. The aberrant transcriptional profile is enriched for neuropsychiatric risk genes. MicroRNA profiling suggests that DGCR8 haploinsufficiency contributes to these effects via dysregulation of genes that control the pace of maturation. Protein-protein interaction network analysis highlights complementary roles for additional deleted genes. Our study reveals consistent developmental and molecular defects caused by 22q11.2 deletions, offering insights into disease mechanisms and therapeutic strategies.

Understanding the impact of long‐term opioid exposure on the embryonic brain is critical due to the surging number of pregnant mothers with opioid dependency. However, this has been limited by human brain inaccessibility and cross‐species differences in animal models. Here, a human midbrain model is established that uses hiPSC‐derived midbrain organoids to assess cell‐type‐specific responses to acute and chronic fentanyl treatment and fentanyl withdrawal. Single‐cell mRNA sequencing of 25,510 cells from organoids in different treatment groups reveals that chronic fentanyl treatment arrests neuronal subtype specification during early midbrain development and alters synaptic activity and neuron projection. In contrast, acute fentanyl treatment increases dopamine release but does not significantly alter gene expression related to cell lineage development. These results provide the first examination of the effects of opioid exposure on human midbrain development at the single‐cell level.