CYSTIC-FIBROSIS IN ARGENTINA - THE FREQUENCY OF THE DELTA-F508 MUTATION

The purpose of the present study is to determine whether the frequency of the Delta F508 mutation in Argentina is similar to the frequency r ecorded in southern European countries (< 50%) (Estivill et al. 1989) considering the European origin of the Argentine population which is m ainly of Spanish and Italian descent. The actual incidence of cystic f ibrosis (CF) in Argentina is as yet unknown, Preliminary data suggest an incidence of 1:4966 live births (Pivetta and Macri 1986). The resea rch was carried out from 1990 to 1994 on 79 unrelated CF patients usin g the polymerase chain reaction (PCR) method. Of over 158 chromosomes studied, the mutation was present in 60.9% of cases. Results are compa tible with the estimated frequency, rather than with the first data pu blished for Argentina, which showed a frequency of 64% (Olek et al. 19 89). As a consequence, perhaps owing to lack of diagnosis in Latin Ame rica (Macri et al. 1990-1991), affected Delta F508 homozygotes are mor e likely to be detected (Pivetta and Luna 1993). In contrast with nort hern European countries, where populations are more homogeneous and th e frequency of Delta F508 is over 70% (Kere et al. 1989), in our count ry mere detection of this mutation does not yield enough information f or genetic counseling purposes. All this suggests the following guidel ines for subsequent studies: (1) direct detection of other mutations s uch as G542X, N1303K, and others - should be included in research; (2) additional methods, such as the study of DNA linked markers, should b e used in genetic counseling; and (3) additional techniques for detect ing mutations (e.g., single-strand conformation polymorphism denaturin g gradient gel electrophoresis) may offer a more precise knowledge of the mutational spectrum characteristics of our country.