Vitamin B12 and Folinic Acid Supplementation in Mitochondrial DNA Deletion Syndromes

"* Vitamin B12 (also known as Cyanocobalamin) daily sublingual supplementation of 1000 mcg/day and folinic acid orally 1mg/day~* Laboratory: Complete blood count, electrolytes, reticulocytes, creatinine, urea, alkaline phosphatase (ALP), alanine transaminase, ferritin, total homocysteine, lactate and hemoglobin A1c. Routine blood will be collected as regular standard of care with each visit. MMA will also be assessed. Peripheral serum values (CBC, B12) will serve as a representation of central micronutrient availability~* Clinical Evaluation: the Newcastle mitochondrial disease adult scale (NMDAS)"