It just occurred to me that it would be really simply to check if there's any prevalence of mitochondrial haplotype in ME patients. Many (but not all) of the genes that code for mitochondrial function are actually present in the mitochondrial genome itself, and not in the chromosomes. These are passed from mother to child. If you have done 23andme (and maybe with other services) you'll get information on your haplogroup. This will be the same as for your siblings (or half siblings by the same mother), maternal blood uncles and aunts, and your maternal grandmother, for example. Note: This doesn't account for all mitochondrial function or genetics, but I just thought it would be quick and maybe interesting to see if any group is overrepresented. @Valentijn - you may know something about this. My maternal haplogroup is H3.