This is one topic I know nothing about
.. First of all, I'm so sorry about
the loss of your sister and what happened afterward.
I found this:
"Much of what we know about these diseases has been discovered since 1940. In 1959, the first patient was diagnosed with a mitochondrial disorder. In 1963, researchers discovered that mitochondria have their own DNA or "blueprint" (mtDNA), which is different than the nuclear DNA (nDNA) found in the cells' nucleus.
Mitochondrial and metabolic medical conditions are now referred to as mitochondrial cytopathies. Mitochondrial cytopathies actually include more than 40 different identified diseases that have different genetic features. The common factor among these diseases is that the mitochondria are unable to completely burn food and oxygen in order to generate energy."
http://my.clevelandclinic.org/disorders/mitochondrial_disease/hic_mitochondrial_disease.aspx
http://dgmweb.net/DNA/General/DNA-Introduction.shtml
Don't know if this helps, Denise