Dr. Gregorio Chazenbalk was born in Buenos Aires Aires , Argentina. He obtained his Ph.D.in Chemistry from the University of Buenos Aires, in 1985. His thesis was based on the thyroid autoregulation at molecular levels. In recognition of this work he was awarded by the Argentine Endocrinology Foundation and the Argentine Society of Endocrinology and Metabolism. In 1986, Dr Chazenbalk joined Dr Basil Rapoport’s laboratory at the Veterans’ Administration Medical Center in San Francisco, California. As a postdoctoral fellow, he was involved in the molecular cloning of human thyroid peroxidase (TPO). In further studies, he demonstrated that TSH regulates messenger RNA levels of different genes, including TPO, in cultured thyroid cells. In 1993, he and his colleagues cloned the entire repertoire of human TPO autoantibodies for the first time. Dr Chazenbalk’s work was also focused in the subunit structure of the human thyrotropin receptor (TSHR), primary antigen of Graves’ disease. A major finding from these studies was that TSHR contains not one, but two, cleavages sites. One of the Dr Chazenbalk ‘s major goals was to engineer the human TSHR A subunit as a highly immunoreactive secreted protein. After 5 years of persisting work, he was able to accomplish this difficult task. The availability of this protein allowed further studies showing its crucial role in either the initiation or amplification of the autoimmune response in Graves’ disease. In summary, Dr Chazenbalk’s work has followed a consistent theme over many years. His strength has been to combine his backgrounds in basic biochemistry with molecular endocrinology. For all his contribution in the field of thyroid regulation and autoimmunity as well as his close mentorship and guidance of many investigators, Dr Chazenbalk received the SLAT Prize in 2001. At this time, Dr Chazenbalk is Associate Professor of Medicine at the University of California, Los Angeles. He works in the Autoimmune Disease Unit, Division of Endocrinology and Metabolism at Cedars-Sinai Medical Center in Los Angeles.