PTPN22 Trp620 explains the association of chromosome 1p13 with type 1 diabetes and shows a statistical interaction with HLA class II genotypes. - Smyth DJ; Cooper JD; Howson JM; Walker NM; Plagnol V; Stevens H; Clayton DG; Todd JA; Smyth, Deborah J; Cooper, Jason D; Howson, Joanna M M; Walker, Neil M; et al. (Diabetes, 2008)