There are hundreds to several thousand mitochondria present in every cell, where they normally have a life span of approximately 40 days before they are degraded. Mitophagy is a natural process where “old” or damaged mitochondria are selectively cleared from the cell. This involves their removal by autophagosomes and subsequent degradation by lysosomes.

Mitophagy plays an essential role in keeping cells healthy, as it promotes the routine turnover of mitochondria and prevents accumulation of dysfunctional mitochondria that would otherwise induce oxidative stress within a cell and lead to cellular degeneration.

Impaired mitophagy has pathological consequences in many rare mitochondrial diseases and in neurodegeneration. The generation of dysfunctional mitochondria and the rate of mitophagy are influenced by a variety of genetic factors, such as inherited or acquired genetic mutations, and by environmental factors such as diet and stress.