A CRISPR-engineered isogenic model of the 22q11.2 A-B syndromic deletion

22q11.2 deletion syndrome, associated with congenital and neuropsychiatric anomalies, is the most common copy number variant (CNV)-associated syndrome. Patient-derived, induced pluripotent stem cell (iPS) models have provided insight into this condition. However, patient-derived iPS cells may harbor underlying genetic heterogeneity that can confound analysis. Furthermore, almost all available models reflect the commonly-found similar to 3 Mb A-D deletion at this locus. The similar to 1.5 Mb A-B deletion, a variant of the 22q11.2 deletion which may lead to different syndromic features, and is much more frequently inherited than the A-D deletion, remains under-studied due to lack of relevant models. Here we leveraged a CRISPR-based strategy to engineer isogenic iPS models of the 22q11.2 A-B deletion. Differentiation to excitatory neurons with subsequent characterization by transcriptomics and cell surface proteomics identified deletion-associated alterations in proliferation and adhesion. To illustrate in vivo applications of this model, we further implanted neuronal progenitor cells into the cortex of neonatal mice and found potential alterations in neuronal maturation. The isogenic models generated here will provide a unique resource to study this less-common variant of the 22q11.2 microdeletion syndrome.

Automated summary

This article describes a method of applying the gene cloning engineering technique to induced pluripotent stem cell models for studying different gene deletions associated with 22q11.2 deletion syndrome. Analysis using transcriptomics and cell surface proteomics reveals deletion-associated alterations in neuronal proliferation and adhesion, and implantation of neuronal progenitor cells into the cortex of neonatal mice shows potential effects on neuronal maturation. These isogenic models provide a unique resource to study this less-common variant of 22q11.2 deletion syndrome.