Even though the mitochondrial morphology was found to be affected e.g., in age mutant Parkinsonian LRRK2(R1441G) mice, mitochondrial shape does not qualify as a biomarker as it is mainly detected in late stages of PD and/or post mortem and inconsistent with the disease pattern (Liu et al., 2020). Here, LRRK2 is linked to Parkinson disease.