Sigh. These are numerous, exquisitely rare, and one cannot help but wonder whether one is wasting one’s time reading about them, given that it is highly unlikely that such a situation will present itself. However, an excellent article is available to the public, and I present it as a reference here so as to be able to revisit this at some later stage.
Another paper presents a handy table of inherited conditions which result in lactic acidosis; I reproduce it below:
Christopher, Rita, and Bindu P. Sankaran. "An insight into the biochemistry of inborn errors of metabolism for a clinical neurologist." Annals of Indian Academy of Neurology 11.2 (2008): 68.
DiMauro S, Schon EA. Mitochondrial respiratory-chain diseases. N Engl J Med 2003;348(26):2656–68.