The MTFS is a powerful sample in which to test endophenotype utility, especially for schizophrenia and other relatively rare disorders. Endophenotypes are hypothesized to be present in unaffected family members of probands, and before the advent of cheap genotyping and known risk loci, familial relatedness was an excellent proxy for genetic risk for disorder. With the help of the PGC results we can rank-order individuals in a community sample by their predicted genetic risk according to measured genetic variants. Thus, even though schizophrenia rates in the present sample are nearly zero, we still have an estimate of each individual’s genetic liability to schizophrenia and, therefore, to endophenotypes truly related to schizophrenia. In the present article we use this sample combined with array-based genotypes, whole genome sequencing, and a variety of statistical approaches to test for relationships between the 108 PGC schizophrenia-associated loci and 17 putative endophenotypes to address these questions: Are any of the 128 PGC schizophrenia-associated single nucleotide polymorphisms (SNPs) also associated with any of our 17 endophenotypes, especially those endophenotypes that show robust phenotypic associations with schizophrenia?Is an
