As succinate also is formed downstream of ABAT activity, and it is involved in mitochondrial physiology, a diagnosis of GABA-transaminase deficiency needs to be differentiated from mitochondrial diseases due to mutations in mitochondrial DNA (Besse et al., 2015) or other aspects of mitochondrial physiology (Ravasz et al., 2017). Here, ABAT is linked to GABA aminotransaminase deficiency.