4q21 is EXACTLY where the CoQ2 gene is located. Shiny's issues are 4q21.1-21.3
CoQ10 is one of those "can't hurt, might help" things. It may not help her physical defects, but it may well help her development and certainly her growth.
Shiny put on 3 pounds in 3 weeks when we started her on CoQ10. You need a form that does NOT have citrates or citric acid in it, as some of the kids have issues with citric acid. Especially if she's on formula, extra citric acid may be problematic. With a baby that age, poking a hole in a softgel and putting the paste in her cheek might work. If she's little, she won't need much, 50 mg, 30 even. I taste tested all of them before giving them to Shiny. Most of the softgel types taste mild, like weak tea, but some of them are very stinging and taste vomity.
CoQ10... there are very few, if any side effects to supplementation, and the amount you have to eat in order to get to toxic levels is closer to pounds. I don't even know if there is an official "toxic" level, it's that innocuous.
Shiny's bloodwork and skin biopsy showed "normal" levels of CoQ10, however, they suspect that her muscles or nerve tissues may have a specific deficiency (which we're not willing to biopsy for) because her response is so clear. If she goes off of CoQ10 for longer than a couple days, she loses language and goes lethargic. She responded to treatment within *days*. When we switched to a form with better absorption, she went from using a few words and able to remember more vocabulary to actually singing.
We got some results from the CoQ10 we bought from costco, Trunature brand maybe? Our best results have been from Vitaline's Smart Q10 chewables.
I did a lot of reading about CoQ10, and put Shiny on with the blessings of researchers into CoQ10 deficiency (they thought she should be on a much higher dose than she ended up needing. At 40 pounds, she's getting 200 mg per day... by their math she would have been on 400 mg per day. But they look at people who are missing two genes for CoQ2, Shiny is only missing one.)