SLC9A9 and hematocrit: However, allele “CC” of rs16854417, an intronic SNP in SLC9A9, identified 3/305 (0.98%) and 4/200 (2%) of HT patients in FHS_Affy500k and in Taiwan_Affy550k, respectively (see Additional file 1: Table S1 for its allele frequencies in various datasets).