RT Journal Article SR Electronic T1 Diagnosis of ‘possible’ mitochondrial disease: an existential crisis JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 123 OP 130 DO 10.1136/jmedgenet-2018-105800 VO 56 IS 3 A1 Parikh, Sumit A1 Karaa, Amel A1 Goldstein, Amy A1 Bertini, Enrico Silvio A1 Chinnery, Patrick F A1 Christodoulou, John A1 Cohen, Bruce H A1 Davis, Ryan L A1 Falk, Marni J A1 Fratter, Carl A1 Horvath, Rita A1 Koenig, Mary Kay A1 Mancuso, Michaelangelo A1 McCormack, Shana A1 McCormick, Elizabeth M A1 McFarland, Robert A1 Nesbitt, Victoria A1 Schiff, Manuel A1 Steele, Hannah A1 Stockler, Silvia A1 Sue, Carolyn A1 Tarnopolsky, Mark A1 Thorburn, David R A1 Vockley, Jerry A1 Rahman, Shamima YR 2019 UL http://jmg.bmj.com/content/56/3/123.abstract AB Primary genetic mitochondrial diseases are often difficult to diagnose, and the term ‘possible’ mitochondrial disease is used frequently by clinicians when such a diagnosis is suspected. There are now many known phenocopies of mitochondrial disease. Advances in genomic testing have shown that some patients with a clinical phenotype and biochemical abnormalities suggesting mitochondrial disease may have other genetic disorders. In instances when a genetic diagnosis cannot be confirmed, a diagnosis of ‘possible’ mitochondrial disease may result in harm to patients and their families, creating anxiety, delaying appropriate diagnosis and leading to inappropriate management or care. A categorisation of ‘diagnosis uncertain’, together with a specific description of the metabolic or genetic abnormalities identified, is preferred when a mitochondrial disease cannot be genetically confirmed.