MITOCHONDRIAL DISEASE??!!

My 10 month old niece, who is currently undiagnosed - we are suspecting mitochondrial disease. . . i dont know much on the causes on a molecular level but the symptoms as i compare when i google the disease are similar.  Involuntary muscle movements, cant suck, her tummy has been tied and she has a tube directly into her intestine, she constantly gags and can not voluntarily move, talk, smile or cry.  She is also always very sweaty and has had quite a few lung infections. . if you know anything or anyone who has been thru this with an infant please let me know.

Thanks