Cystic Fibrosis (CF) is one of the most common single-gene defects in European descent populations with an incidence of about 1 in every 2500 live births and carrier frequency of approximately 1 in 25. The most common mutation at the CF transmembrane conductance regulator (CFTR) gene is a deletion (p.F508del) of the phenylalanine codon 508; its frequency, however, is not the same throughout the world. The purpose of this paper is to document an application of a two-tier survey design in different states of Brazil, from which regional differences of the incidence of CF and frequency of CF-causing mutation(s) carriers can be for the first time estimated. We present data on genotype distributions in reference to p.F508del mutation in samples of newborns, adult controls and CF patients from five Brazilian states, in which a total of 2683 newborns born to Brazilian white parents and 500 African-Brazilians adult controls were screened, as well as 300 CF patients (262 European descents and 38 African descents) were genotyped. Our results suggest that the CF-incidence in different parts of Brazil may differ by almost 20-fold. For the five different states as a whole, nearly 48% of the CF-alleles carry the p.F508del mutation, which places the estimates of disease incidence and carrier frequencies for the Brazilian European descents as 1 in 7576 live births and 2.3%, respectively. The implications for prevention of CF and other rare Mendelian diseases through such surveys of mutation screening are discussed.

We conducted a retrospective study of 743 patients with cystic fibrosis (CF), covering the 1979-89 period in 4 Latin American (LA) institutions to evaluate the clinical features of the disease. The review, although dealing only with patients referred to, or diagnosed at these institutions may be considered to comprise the majority of patients living in these areas. Diagnosis was confirmed by the sweat test in all cases. There was a slight predominance of males, (61.0%) mainly in the Brazilian group. The mean age at diagnosis was over 3 years. This was similar to the mean age at admission. Almost half of the patients were still alive at follow-up, but their mean age was low (6.4 years in Brazil, 7.4 in Chile, 9.6 in Mexico, and 11.3 in Argentina). Mean age at death ranged from 3.1 years (Chile) to 8.7 years (Argentina). The highest proportion of living patients was in Chile (71.4%) and the lowest in Argentina (33.8%). Survival curve comprised 15 years after diagnosis for the Argentinian group, compared to 6 years for the remaining groups. Fifty percent of the patients lived 6-7 years after diagnosis in Argentina, 4-5 years in Mexico and Chile, and 3 years in Brazil. Among Argentine patients 39.2% survived to 10 years of age, and 18% to 15 years. These findings suggest that CF is not rare in LA but extensive epidemiological studies are needed to obtain accurate figures on the magnitude of the problem.

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