In this case, we present a Chinese family exhibiting a rare and severe early progressive encephalomyopathy, diagnosed with mitochondrial DNA depletion syndrome, type 5 (MTDPS-5), and carrying compound heterozygous variants (c.1234C>T; g.48569263–48571020del1758insATGA) in the SUCLA2 gene. The gene discussed is SUCLA2; the disease is mitochondrial DNA depletion syndrome, encephalomyopathic form with methylmalonic aciduria.