fibroblast rs1440072 223936738 KCNE4 chr2_223935000_223940000 chr2_223910000_223915000 fibroblast rs5838980 223936983 KCNE4 chr2_223935000_223940000 chr2_223910000_223915000 fibroblast rs6436371 223944809 KCNE4 chr2_223940000_223945000 chr2_223915000_223920000