Sequencing of other nuclear genes that are associated with CPEO and multiple mtDNA deletions, such as; POLG1, POLG2, TK2, ANT1, DGUOK, MPV17 and RRM2B did not reveal any pathogenic mutation in patients with C10orf2 mutation.
Exome sequencing efficiently and effectively identified a novel, homozygous missense variant in RRM2B, which was strongly suggested to be causative for arPEO.