The cystic structures observed in Hesx1Cre/+;R26rtTA/+;Col1a1tetO-Yap/+ mutants were reminiscent of Rathke’s cleft cyst (RCC), which is a benign developmental anomaly of the pituitary characterised by the presence of ciliated and secretory cells, expression of cytokeratins and frequent expression of p63. This evidence concerns the gene YAP1 and central nervous system cyst.