Summary: Purpose: Study of families containing multiple affected individuals is essential for genetic research on the epilepsies, yet practically nothing has been published about methods for identification and recruitment of families or expected participation rates. Here we describe the strategy used for data collection in a genetic linkage study, to provide guidelines for efficient design of new studies.
Methods: Potentially eligible families were ascertained from private physicians, clinics, and self-referrals. Participation rates were examined at each step of the recruitment process, according to ascertainment source, initial contact method, gender, and ethnicity.
Results: Among 320 potentially eligible families identified, only 68 (21%) were successfully enrolled. Contact was established with an index subject in 83% of families, and a screen for eligibility was completed in 88% of these. However, only 54% of screened families were confirmed to be eligible, and of these, only 54% were enrolled. In eligible families, 79% of index subjects agreed to participate; the low family enrollment rates resulted largely from refusals by other family members whose participation was needed for linkage analysis. At each step in the recruitment process, the participation rate was higher in self-referred than in other families.
Conclusions: Recruitment of families for genetic studies is labor-intensive; many potentially eligible families may have to be screened for each family enrolled. Recruitment is easier with self-referred families than with those identified through other methods. The introduction of standardized methods for identification of eligible families from clinical settings can improve efficiency.