We describe an Irish family with a rarely reported Twinkle mutation, in whom mild late onset ocular myopathy was associated with widespread myalgia and raised CPK in the index case. Six family members were affected by ptosis and inheritance was autosomal dominant. The symptom onset appeared to correlate with statin therapy. Muscle biopsy revealed numerous COXc deficient ragged red fibres and Complex IV deficiency. An R357P mutation in Twinkle was identified. This mutation has previously been reported in just one Spanish kindred. The disease in this family appears particularly mild.