The results of the combined polygenic VC linkage analysis showed that the genes Treacher Collins-Franceschetti syndrome 1 (TCOF1) and GRK6 share a strong and significant genetic correlation (ρg = 0.94 ± 0.07, p < 0.0001), implying these two expression traits may share susceptibility genes at that locus, and that these two expression traits may be regulated by the same SNP. The gene discussed is GRK6; the disease is Down syndrome.