Quality of Life in Adult Patients with Mitochondrial Myopathy

Mitochondrial myopathies (MM) are caused by impairment of the respiratory chain [1] . They are some of the most common inherited neuromuscular disorders, with an estimated prevalence of 1 1/10,000 [2] . Uncomplicated MM (without major multisystem involvement) do usually not shorten the duration of life but rather involve the quality of life. A recent study has shown that mothers of children with mitochondrial disease had a significantly higher caregiver burden and poorer quality of life, particularly related to role limitations, vitality and mental health, compared with a group of mothers of children with intractable epilepsy and without mitochondrial disorder [3] . However, surprisingly, any studies addressing the issue of the quality of life in adult patients with MM are not available to date. The objective of this study was to evaluate if there was a relationship between quality of life and disease progression in MM. We studied a group of 26 patients (18 females, 8 males; mean age 54.4 8 11.9 years; 8 with mitochondrial DNA single deletion, 16 with multiple deletions) with pure MM [4] and without prominent comorbidities, by a scale of quality of life (SF-36) [5] , a spe