P5.41 ATP synthase deficiency: A diagnostic strategy for not such an uncommon cause of OXPHOS dysfunction

Abstract

Until recently, ATP synthase deficiency was considered as a relatively rare cause of OXPHOS dysfunction, mainly due to pathogenic alterations in the mtDNA. The last two years an emerging group of patients with complex V defects of nuclear origin have been reported. The majority of these displayed homozygous TMEM70 mutations. However, technical difficulties for evaluating complex V activity and the heterogeneous clinical picture of patients seriously hamper correct identification. Therefore, we postulate that complex V deficiency of nuclear origin is under-diagnosed.