VPS13A and Choreoacanthocytosis: Chorein, the VPS13A gene expression product, is ubiquitously detected in a wide variety of human tissues (Dobson-Stone et al., 2004), which has been proven to be markedly reduced or absent in ChAc patients with the mutations described above (Dobson-Stone et al., 2004; Velayos-Baeza et al., 2004).