RGPD4 and idiopathic pulmonary fibrosis: We initially provide evidence that RGPD4 variants might participate in the development of SSc-ILD in comparison to the other two groups upon SKAT analysis (P = 8.13 × 10-7, P-FDR = 0.015, OR = 17.23), especially LoF with a severe ILD phenotype (radiological pattern: UIP).