PLACK syndrome, caused by biallelic loss-of-function (LOF) variants in the CAST gene, is an ultra-rare autosomal recessive disorder characterized by the following defining dermatologic features: peeling skin, leukonychia, acral punctate keratoses, cheilitis, and knuckle pads (PLACK) [1]. This evidence concerns the gene CAST and peeling skin-leukonuchia-acral punctate keratoses-cheilitis-knuckle pads syndrome.