Inspired by this observation, and considering the well-known toxicological effects of H2S — whereby H2S exerts inhibits mitochondrial ATP generation by inhibiting mitochondrial Complex IV [7,8] — in the early 2000's Pierre Kamoun, a biochemist and physician colleague of Lejeune has put forward the hypothesis that CBS-derived overproduction of H2S may contribute to the pathogenesis of DS. This evidence concerns the gene CBS and Dravet syndrome.