No evidence for segregation distortion of cystic fibrosis alleles among sibs of cystic fibrosis patients
Abstract
In 1988, an excess of male carriers of cystic fibrosis (CF) mutations among sibs of CF patients was reported by Kitzis et al. [1]. In particular, a significant deviation from a 1:1 sex ratio was observed among heterozygous carriers in favor of males, and among homozygous normals in favor of females.
When the study reported by Kitzis et al. [1] was carried out, before the identification of the CFTR gene, carriers were detected by means of RFLPs tightly linked to the CF locus. Following the identification of the CFTR gene, direct carrier detection has become possible in those CF families where mutations are identified, thus avoiding possible errors deriving from misdiagnosis and/or recombination with the linked markers.
We decided, therefore, to further investigate the question of a possible sex ratio distortion among carrier sibs of CF patients taking advantage of the large amount of data already available. Only families which were not included in the analysis done by Kitzis et al. [1], and in which both the paternal and the maternal mutations were identified, were included in the present analysis.