Mitochondrial disease is not a disease per se, but I broad category of all kinds of both nuclear and mitochondrial mutations. Some of them are fatal and kids di

Mitochondrial disease is not a disease per se, but I broad category of all kinds of both nuclear and mitochondrial mutations. Some of them are fatal and kids die within days or years after birth and some are more like chronic conditions with a varying degrees of severity. In my case, my genotype is a single, large-scale mtDNA deletion. It is heteroplasmic, meaning that some of my mitochondria are normal and some are mutant. In these type of mutations, heteroplasmy percentage drives disease severity. Disease is also progressive. Mutant mitochondria have a replication advantage, so that the percentage of mutant mitochondria goes up as you age. My phenotype is called CPEO (Chronic Progressive External Ophthalmoplegia), probably the most common and benign disease presentation. I have ptosis (droopy eyelids) and diplopia (double vision). Both corrected by surgery. I have also some systemic symptoms, mostly a profound "fatigue" that hits me 2-3 days per month. I quote fatigue because it is a unique feeling not like normal fatigue. Malaise could be also a good definition. I am lucky. I have a normal life with minor issues. A good diet and exercise made a huge difference. I also take some over the counter supplements that also help my body to cope with all the mutant mitochondria.