Mitochondrial diseases

Sometimes I work on a case with a rare disease. In one year, I probably come across 5-8 rare diseases, which of course I have to look up because, well, what the hell is this?

One kind of disease that scare me are mitochondrial diseases. These are a group of conditions that are caused by genetic mutations in the mitochondrial DNA that make the mitochondria work abnormally. And if you remember anything about high school biology, mitochondrial are the “powerhouses” of the cell — they produce energy for us to use. So one can imagine that if you have something wrong with your power source, you can’t carry out normal functioning. Also, mitochondrial DNA are only carried in the egg cells, so only mothers can pass this down to their children. Sperm cells don’t carry and therefore don’t contribute mitochondria to the next generation.

It’s crazy how such a small thing can generally f*&k up a life. The US Health & Human Services National Institutes of Health website lists common signs and symptoms such as: poor growth, loss of muscle coordination, muscle weakness, seizures, autism, problems with vision and/or hearing, developmental delay, heart/liver/kidney disease, gastrointestinal disorders, dementia, to name some. You can see what mitochondrial diseases affect in this list of free text research articles at PubMed (I don’t have any institutional access, so I look for free text articles). Then I thought about prenatal testing, and found an article that discusses this, a more recent 2021 article of a study in Japan, and recent (as of 2017) advances in mitochondrial diseases. This article from 2020 is about rare genetic diseases in general, and diagnosing them. If there’s anything I’ve learned from skimming through these articles, it’s that there’s still so much we don’t know. Yet.