Two new mitochondrial diseases have been described: an encephalomyopathy caused by mutations in C12orf65 leading to a mitochondrial translation defect (Antonicka et al., 2010, Am J Hum Genet 87:115-22). The mutated protein is thought to help tRNA processing during mitochondrial protein elongation.
Also, mutations in the X-linked AIFM1 gene, encoding the protein Apoptosis-Inducing Factor Mitochondrion-associated 1, can cause a severe mitochondrial encephalomyopathy (Ghezzi et al., 2010, Am J Hum Genet. 86:639-49). The protein is implicated in a type of apoptosis with caspase-independent fragmentation of chromosomal DNA, a process referred to as parthanatos and mediated by poly(ADP-ribose).
Philippe Campeau, MD