Our analysis identified a subgroup of six DEGs out of 171 DEGs characteristic of the RHD vs. ARF group that are known to play a role in tryptophan metabolism (a pathway that houses tryptophan biosynthesis as a sub-pathway), including THP1, THP2, AFMID, CYP1A1, CYP1A2 and ALDH7A1 to be downregulated indicating that tryptophan metabolism may get further downregulated during the progression of ARF to RHD. The gene discussed is CYP1A2; the disease is rheumatic fever.