A child with cystic fibrosis: I. Parental knowledge about the genetic transmission of CF and about DNA-diagnostic procedures.

In 1984, we interviewed 105 Belgian families with a Cystic Fibrosis (CF) child in order to evaluate their knowledge about the genetic aspect of CF. Three years later, in 1987, they received a mailed questionnaire to assess how well they were informed about the new possibilities of DNA diagnosis. In 1984, three out of the four families were aware of their 25% recurrence risk in subsequent pregnancies. The proportion of correct answers rose to 87% in 1987. The risk that relatives may be asymptomatic carriers was less well known. Only 17% knew that the risk that their own brothers and sisters are carriers of the CF-gene was 1 in 2. The probability that their own healthy children would be carriers of the CF-gene was not known at all. Half of the families who returned the questionnaire thought they were well informed about the new possibilities of DNA-analysis for prenatal diagnosis. The limitations of DNA analysis, however, were poorly understood. The information transfer about the genetic transmission of CF and related topics within the family was also investigated.