After an initial gen@ome-wide linkage study in 12 families of INAD patients revealing a spectrum of mutations in the PLA2G6 gene [38], a number of missense or frameshift mutations in the PLA2G6 gene have been identified, accounting for approximately 85% of INAD patients [39]. Here, PLA2G6 is linked to neurodegeneration with brain iron accumulation 2A.