**5. Conclusions**

This study used a population genetics approach to investigate the association of *MT-CYB* mutations with ARF and RHD in Senegalese patients. The present results confirmed our initial hypothesis. Indeed, sixty polymorphic variants of *MT-CYB* were identified herein. Some of these mutations were neutral, while other mutations were pathogenic, as revealed through their effects on cytochrome b structure and function. Furthermore, the absence of more than half of these mutations in patients with valvular replacement and genetic differentiation between the latter and unoperated patients indicates *MT-CYB* polymorphisms, which are closely associated with ARF and RHD. These mutations cause or result from abnormal activation of immune cells against autoantigens. A study combining both immune assessment with a genetics approach would be interesting to clarify why only some individuals infected with group A streptococcus develop an inadequate immune response leading to ARF. A subsequent analysis of the protein would also provide useful insights into the role of cytochrome b in ARF and RHD. In addition, DNA extraction in the same patient before and after surgery could validate our results.

**Author Contributions:** Conceptualization, F.B.W. and F.M.; Data curation, F.B.W.; Formal analysis, F.B.W.; Investigation, F.B.W. and M.P.S.; Methodology, F.B.W.; Project administration, F.M.; Resources, M.S.; Software, F.B.W.; Supervision, F.M. and M.S.; Validation, F.M. and M.S.; Visualization, F.B.W. and F.M.; Writing—original draft, F.B.W.; Writing—review and editing, F.M.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
