SLC29A3 and Leukoencephalopathy: On ClinVar, DARS2 p.R263Q is classified as pathogenic by a single submitter associated with the condition of leukoencephalopathy with brain stem and spinal cord involvement and lactate elevation, whereas SLC29A3 p.M116R is pathogenic without assertion criteria and linked to histiocytosis-lymphadenopathy plus syndrome.