The co-occurrence of PWS and additional autosomal recessive conditions (e.g., congenital ichthyosis linked to a homozygous pathogenic variant in the ceramide synthase 3 (CERS3) gene and hereditary spastic paraplegia type 11 linked to the spatacsin (SPG11) gene, STRC/CATSPER2-deletion-mediated deafness/infertility syndrome, Bloom syndrome and Tay–Sachs disease) has been previously reported in the literature [14,15]. Here, SPG11 is linked to inherited ichthyosis.