Keratoderma and ichthyosis as valuable features for the diagnosis of CEDNIK syndrome

Cerebral dysgenesis, neuropathy, ichthyosis, and keratoderma (CEDNIK) syndrome is a rare autosomal recessive neurocutaneous disorder caused by a loss-of-function mutation in the SNAP29 gene.1 This gene encodes synaptosomal-associated protein 29 (SNAP29) required for vesicle trafficking during exocytosis, endocytosis, autophagy, ciliogenesis, and other cellular events.2-4 Decreased expression of SNAP29 in the skin results in an abnormal maturation of lamellar granules, which are organelles that are most likely found on the upper epidermal layers with the role of properly delivering lipids, proteases, and their inhibitors to the stratum corneum.