Recently, a member of the GATA-binding family of transcription factors was shown to be involved in the human hypoparathyroidism, sensorineural deafness and renal anomalies (HDR) syndrome. Deletion-mapping studies and subsequent mutation analysis revealed that haploinsufficiency for GATA3 is the underlying mechanism of the HDR syndrome. Here we discuss the clinical characteristics of the HDR syndrome and present an overview of the role of GATA3 and related GATA-binding transcription factors during vertebrate embryonic development and their involvement in human disease.