However, with identification of the PLA2G6 gene, it has become clear that there is also pathological heterogeneity in NAD, as cases with clinical and pathological features of INAD were found to be negative for PLA2G6 mutations and patients with PLA2G6 mutations have been identified without axonal spheroids (Gregory et al., 2009). This evidence concerns the gene PLA2G6 and neurodegeneration with brain iron accumulation 2A.