Reply: DARS2 gene clinical spectrum: new ideas regarding an underdiagnosed leukoencephalopathy

Sir, We thank Drs Bocca Vieira de Rezende Pinto and Sgobbi de Souza for their interest in our recent overview paper on a cohort of patients with leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL), caused by DARS2 mutations (Van Berge et al. , 2014). Their letter provides us with the opportunity to make specific points clearer. The authors give a summary of the information published to date and pay special attention to exceptional cases, such as described by Miyake et al. (2011) and Synofzik et al. (2011). Additionally, they comment that magnetic resonance spectroscopy does not invariably reveal elevated lactate in patients with LBSL. They therefore suggest replacing the name LBSL by ‘ DARS2 -related conditions’ or ‘ DARS2 -related spectrum disorders’. We agree that the use of an acronym as the name for a disease may suggest that all patients fulfil all letters of the acronym at all stages of the disease. What is …