Early studies show enrichment of the HLA-A*09 subgroup allele HLA-A*24 in dcSSc, and HLA-A*30 and HLA-A*32 risk associations have also been reported in Caucasian and Brazilian populations, the former associated with risk of pulmonary hypertension and pulmonary fibrosis in SSc patients (Gladman et al., 2005; Del Rio et al., 2013). Here, HLA-A is linked to pulmonary arterial hypertension.