POLG and neurodevelopmental disorder: Specifically, we found variants in the POLG gene (which is associated with a range of mitochondrial disorders, including ataxia), BRAT1 gene (which is linked to a neurodevelopmental disorder with ataxia, intellectual disability, and other neurological features), NARS2 gene (related to a condition known as NARS2-related disorders which can include ataxia among other symptoms), and MT-ATP6 gene (which is associated with mitochondrial disorders that can manifest with ataxia and other neurological problems) in four patients.