APTX and ataxia telangiectasia: Notably, mitochondrial pathogenesis characterizes a significant subgroup of ARCAs, and such as FRDA, POLG-related ataxia, ARSACS, and SPG7, in which mutations of nuclear genes directly affect mitochondrial proteins, but also other forms, such as Ataxia-Teleangiectasia (AT), Ataxia-Teleangiectasia Like disease (ATLD), Ataxia with Ocular Apraxia 1 and 2 (AOA1, AOA2), Spinocerebellar ataxia with axonal neuropathy1 (SCAN 1), in which mitochondrial functions are also indirectly compromised.