ALDH5A1 and succinic semialdehyde dehydrogenase deficiency: Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare genetic disease associated with mutations of the ALDH5A1 gene, tissue accumulation of neuromodulators including γ‐aminobutyric acid (GABA) and γ‐hydroxybutyric acid (GHB), and tissue depletion of glutamine (gln), the precursor of GABA and glutamic acid (glu).