Fatal Infantile Lactic Acidosis with Methylmalonic Aciduria is related to mitochondrial dna depletion syndrome. An important gene associated with Fatal Infantile Lactic Acidosis with Methylmalonic Aciduria is SUCLG1 (Succinate-CoA Ligase GDP/ADP-Forming Subunit Alpha). Affiliated tissues include skeletal muscle, and related phenotypes are methylmalonic aciduria and methylmalonic acidemia