The study was renewed in 1999 through 2003 to expand the registry in order to obtain enough PPH families to localize and clone the PPH gene, and support the DNA bank for these and further studies. Other goals included prospective and biochemical mediator studies of obligate gene carriers, who did not have clinically evident PPH. This aim determined which mediators first became abnormal during developing PPH, and defined the natural history of pre-symptomatic diseases. In addition, the registry broadened its scope to include sporadic PPH patients, including those who had used appetite suppressant medications, who were screened for gene mutations.