Two haplotypes in the HTR1A and RNF180 area in the Swedish and Danish families; a haplotype containing rs6295 (C) – rs356570 (A) – rs6880454 (G) showed positive association to T1D (p<0.002 and p<0.05 respectively) while haplotype rs878567 (T) – rs6449693 (G) – rs6295 (G) – rs356570 (G) showed protective association (p<0.03 and p<0.02, Table 4). This evidence concerns the gene RNF180 and type 1 diabetes mellitus.