Following the analysis of the siblings, subsequent analyses were conducted using the singleton individuals (i.e. those with no genetic data from other family members). The analysis of the singletons (which could not be included in the PBAT analysis due to lack of family genotypic information) was done in SPSS version 15.0 and SAS version 9.1 using Chi Square tests for binary traits and ANOVA/regression models for continuous traits. In SPSS and SAS ethnicity was included as a covariate when possible, and also the subset of Caucasians was examined separately. Thus two sub-samples were generated from the genetic sample: the group of individuals with sibships who were analyzed with PBAT, and the singletons group, analyzed using SAS and SPSS. Significance levels from the two samples were combined using Fisher’s Method where appropriate.
