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Cystic fibrosis: low frequency of DF508 mutation in 2 population samples from Rio de Janeiro, Brazil
G M Cabello1, A F Moreira, D Horovitz
1Departamento de Genética, Instituto Oswaldo Cruz, Rio de Janeiro, Brazil.
Insights
The DF508 mutation is less common in Rio de Janeiro
Area of Science:
- Medical Genetics
- Population Genetics
Background:
- Cystic Fibrosis (CF) is a genetic disorder.
- The DF508 mutation is the most common CF-causing mutation globally.
Purpose of the Study:
- To determine the frequency of CF mutations in Rio de Janeiro.
- To estimate the incidence of CF in this Brazilian population.
Main Methods:
- Genotyping of CF patients and healthy individuals for CF mutations.
- Analysis of DF508 allele frequency.
- Calculation of CF incidence based on mutation frequencies and population admixture.
Main Results:
- DF508 allele frequency in Rio de Janeiro is lower than the global average.
- Observed frequencies for G542X and G551D mutations.
- Estimated CF incidence varies depending on ethnic admixture considerations.
Conclusions:
- The lower DF508 frequency may be linked to Rio de Janeiro's diverse ethnic background.
- CF incidence in Rio de Janeiro is estimated between 1:3542 and 1:6902.
- Further research into CF genetics in admixed populations is warranted.
Abstract:
Blood samples from 44 unrelated cystic fibrosis (CF) patients from Rio de Janeiro, Brazil, were analyzed for the 8 European CF mutations. Six homozygous and 15 heterozygous carriers of the DF508 mutation were found, corresponding to 47.7% of CF patients (allele frequency 0.3068). The G542X and G551D mutations were also observed with allele frequencies of 0.0227 and 0.0114, respectively. An analysis of the DF508 mutation in 291 randomly chosen, healthy individuals was performed, and only 3 heterozygous carriers were identified. These results show that the frequency of the DF508 allele in Rio de Janeiro is much lower than the world average; this may be due to the extremely heterogeneous ethnic admixture of the study population. By combining the results of these 2 different samples (CF patients and random population) and admixture data from Rio de Janeiro, we can estimate the CF incidence in this population to be 1:3542 individuals. However, taking into account the Rio de Janeiro ethnic admixture, we can find an estimate of 1:6902 individuals.
