B2M and autosomal dominant optic atrophy: To test this hypothesis, we compared the mtDNA content by analyzing the levels of the mitochondrial gene ATP synthase protein 8 (MT-ATP8) and the mitochondrial D-loop region compared to the single copy β2 microglobulin (B2M) nuclear gene25 and observed no differences between neutrophils of ADOA patients and healthy controls (Fig. 1d).