To determine the differences in physiological functions between CRG cluster A and B, gene set variation analysis (GSVA) was used to perform Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of CRG cluster A and B. The GSVA results suggested that immune-related pathways, including graft-versus-host disease, intestinal immune network, JAK-STAT signaling pathway, cytokine‒cytokine receptor interaction and Toll-like receptor signaling pathway, were obviously enriched, indicating that immune-associated physiological functions were different in groups A and B (Fig. 2B). Here, CHD7 is linked to graft versus host disease.