This article summarizes pituitary development and function as well as specific mutations of genes encoding the following transcription factors: HESX1, LHX3, LHX4, POU1F1, PROP1, and OTX2. Although several additional genetic defects related to hypopituitarism have been identified, this article focuses on these selected factors, as they have been well described in the literature in terms of clinical characterization of affected patients and molecular mechanisms of action, and therefore, are very relevant to clinical practice.