Heterozygous missense variant in GLI2 impairs human endocrine pancreas development
To study the impact of an heterozygous missense variant in GLI2 in pancreatic cell differentiation and function, we established a patient-like pluripotent stem cell model. Interestingly, engineered iPSC lines carrying the identified missense variant in the gene GLI2 showed impaired differentiation into endocrine progenitors.  To further characterize putative downstream mechanisms underlying the impaired endocrine differentiation of iPSCs, we performed bulk RNA-seq at three stages of differentiation (iPSC, gut tube and endocrine progenitor stages). At early stages (iPSC and gut tube stage), the transcriptome of GLI2-CTRL and GLI2-MUT-derived cells was highly comparable, with only 48 genes significantly dysregulated at gut tube stage. By contrast, differences at the transcriptome level became evident at endocrine progenitor stage [928 genes upregulated and 1070 downregulated in mutant versus control cells]. Overall design: Comparative gene expression profiling analysis of RNA-seq data for human iPSC cells [control and mutant (MUT) lines] at two stages of pancreatic differentiation (PD)