Five variants of the beta-globin gene without clinical or hematological effects: Hb Maryland [beta 47(CD6)Asp-->His], Hb Kent [beta 37(C3)Trp-->Cys], Hb Visayan [beta 136(H14)Gly-->Cys], Hb Cutlerville [beta 138(H16)Ala-->Val] and Hb Hornchurch [beta 43(CD2)Glu-->Lys].
Source:http://linkedlifedata.com/resource/pubmed/id/18932072
