PINK1 and diabetes mellitus: Since blood is a highly accessible bodily fluid compared with CSF, additional research is needed to clarify to what extent (e.g., concentration of protein) and under which conditions (e.g., comorbidities such as diabetes or other metabolic alterations) serum levels of PARKIN and especially PINK1 can serve as biomarkers capable of distinguishing patients with RRMS in the acute phase from patients with other neurological disorders such as NMOSD or MOGAD.