FASTKD2 and lactic acidosis: Summing up the data of the nine patients belonging to seven families with FASTKD2 variants, we found that there is high variability in both the genetic and phenotypic spectra with lactic acidosis and stroke-like episodes (MELAS) (Yoo et al., 2017; Shah and Balasubramaniam, 2021), infant-onset encephalomyopathy (Ghezzi et al., 2008; Wei et al., 2020), and new-onset refractory status epilepticus (Astner-Rohracher et al., 2023).