PSMD1 and ichthyosis: Nonetheless, diseased models such as CEDNIK (Cerebral dysgenesis–neuropathy–ichthyosis–keratoderma) syndrome caused by a mutation in the SNARE protein SNAP29 and MEDNIK (mental retardation, enteropathy, deafness, neuropathy, ichthyosis, keratoderma) syndrome caused by S1 subunit of AP1 (AP1S1) are associated with LB dysfunction and severe ichthyosis conditions (Montpetit et al., 2008; Fuchs-Telem et al., 2011; Martinelli and Dionisi-Vici, 2014; Schiller et al., 2016).