[Family screening for HBB*S gene and detection of new cases of sickle cell trait in Northeastern Brazil].

Objective: To estimate the additional number of affected individuals based on the prevalence of sickle-cell syndromes among relatives of index cases.

Methods: Cross-sectional study of relatives of a random sample of index cases identified through a neonatal screening program in Northeastern Brazil, between 2001 and 2005. The extended family trial model included 463 relatives of 21 index cases.