With AA and mixed families excluded, we have 3,016 out of 3,567 EA individuals from 453 families genotyped on microsatellite markers in the LinkageMS data. 471 of these individuals in 398 linkage families were selected for SNP genotyping (known as the mutual individuals) ( Table 6 ), including 41 individuals without microsatellite genotyping data. For GWAS, from each of these 398 families, one affected child (normally the proband) was selected as the case and other biologically unrelated family member(s) were used as the control. In total, 1,399 EA CIDRSNP individuals consist of 847 cases and 552 controls. Figure 3 shows the pedigree of one of the LinkageMS EA families (FAM_ID 20059). This family has four mutual individuals. Except for proband #1, all the other three (#2, 9, and 13) selected for GWAS are relatives by affinity to this family.
