Genetic requirement for <i>Esrp1</i> and <i>Esrp2</i> in vertebrate pituitary morphogenesis

The pituitary gland produces several hormones that regulate growth, metabolism, stress response, reproduction and homeostasis. Congenital hypopituitarism is a deficiency in one or more pituitary hormones and encompasses a spectrum of clinical conditions. The pituitary has a complex embryonic origin, with the oral ectoderm contributing the anterior lobe, and the neural ectoderm generating the posterior lobe. Pituitary abnormalities and growth deficiencies are associated with cleft palate; however, the developmental genetic connection between pituitary and orofacial cleft malformations remains to be determined. The epithelial RNA splicing regulators Esrp1 and Esrp2 (Esrp1/2) are required for orofacial development in zebrafish, mice and humans, and loss of function of these genes results in a cleft palate. Here, we present a detailed developmental analysis of the genetic requirement for Esrp1/2 in pituitary morphogenesis in mouse and zebrafish. Further, we describe an individual with cleft palate and hypopituitarism who harbors a nucleotide variant in the RNA-binding domain of ESRP2. The discovery of this key function for Esrp1/2 in pituitary formation has significant fundamental and clinical implications for understanding congenital hypopituitarism and craniofacial anomalies.