passages.id: split_1_test_3351_passage
passages.type: progene_text
passages.text: We performed a multitiered , case - control association study of psoriasis in three independent sample sets of white North American individuals ( 1 , 446 cases and 1 , 432 controls ) with 25,215 genecentric single - nucleotide polymorphisms ( SNPs ) and found a highly significant association with an IL12B 3' - untranslated - region SNP ( rs3212227 ) , confirming the results of a small Japanese study .