Single-gene enrichment analysis showed that IFI6 and FSCN1 were enriched in the intestinal immune network of the immunoglobulin A production pathway in SSc (Figure 8A, B), whereas IFI6 and FSCN1 were enriched in the primary immunodeficiency signaling pathway in patients with AS (Figure 8E, F). The gene discussed is FSCN1; the disease is systemic sclerosis.