As I understand it, Justina has never been confirmed through testing to have a mitochondrial disorder. From everything I have read, there are no real definitive tests for mitochondrial disorders.
One of the things that I have read about Munchausen’s is that the affected parent often homes in on a disease whose symptoms are vague, and which cannot be definitively ruled in or out by testing.
The bottom line is that we do not know enough about this case (having only heard one side of the story) to know whether Justina is genuinely ill, or if she has been made ill through the actions of her mother.
No direct definitive tests...but there are tests for anti mitochondrial antibody and the like. The previous treatments seem to have helped her n the past to keep her weight and function before the state took them away. The state seems to be going with a “if we isolate the girl from bad parents, her natural survival instincts will take over and she’ll tire of the whole psych thingy and she get better on her own” strategy. It doesn’t seem to be working. I don’t think she’s faking it.
If the girl has a somatoform illness, it may be specific to the girl and is nothing the parents are doing.