Screening for cystic fibrosis - the Brittany experience

Professor Claude Ferec, Laboratory for Molecular Genetics, Brest, France

We set up a systematic screening programme in Brittany, France – a region of 2.8 million inhabitants of mostly Celtic origin and with one of the highest incidence of CF in Caucasians.

The programme was based on the immunoreactive trypsin from dried blood spots combined with a direct search for gene mutations into the screening process. We describe the results of 16 years experience of neonatal screening in Brittany, with 565 newborns screened for CF. 195 children were found to be carriers of two mutations in the CFTR gene giving an incidence of 1/2885.

We have evaluated the impact of neonatal screening during that period. Over the same period we collected data from prenatal diagnosis carried out in the region, first in families related to a CF child and also those made following the detection of an echogenic bowel upon routine ultrasound examination performed during pregnancy.

By including the CF affected pregnancies that were terminated during these years the corrected birth prevalence of CF was 1/972. This is a precise measure of CF birth prevalence and of its evolution through the combined effect of neonatal screening, prenatal diagnosis, ultrasound examination and family testing. The ethical aspects of this programme including carrier screening and atypical genotype of some children will be discussed.