PEX16 and Zellweger syndrome: Intriguingly, case studies of PEX16 mutations have also documented atypical Zellweger spectrum disorder phenotypes including dystonia, cerebellar ataxia, corticospinal tract degeneration, peripheral neuropathy and spasticity, with normal levels of VLCFAs (Kumar et al., 2018; Ebberink et al., 2010).