Fig. 1

Distribution of HLA-DRβ1 3rd HVR sequences according to charge and parental inheritance. Colors represent the overall 3rd HVR charge for each (biallelic) individual, considering both maternal and paternal haplotypes; red, overall charge was negative; yellow, overall charge was neutral; and green, overall charge was positive. Among SSc patients there was marked skewing of parental inheritance when the 3rd HVR sequence carried a +2 charge (p = 0.0003, p _c = 0.001) whereas controls showed a similar frequency of inheritance from either parent, as would be expected. Skewing was also observed, to a lesser extent, among SSc patients when the 3rd HVR sequence carried a 0 charge (p = 0.021, p _c = 0.08). Columns and rows with a −1 charge are 0 because no study subject had a 3rd HVR sequence with this charge (Color figure online). SSc systemic sclerosis