Renal oncocytomas, associated with the accumulation of defective mitochondria, can occur sporadically and in associated with inherited conditions such as BHD. Sporadic forms have been linked to mitochondrial genome (mtDNA) mutations that disrupt respiratory chain complex I. New research from Lang et al., (2015) determined that similar mutations were present in sporadic bilateral and multifocal oncocytomas but not BHD tumours enabling distinctions between the two. Lang et al. also showed that sequencing mtDNA from biopsy samples was predictive of tumour mtDNA enabling reliable preoperative diagnosis.