The correct answer is A. SLURP-1.

Attached picture is Mal de Meleda (keratosis palmoplantaris transgrediens) which is an autosomal recessive form of diffuse PPK, associated with keratotic plaques that extend to the dorsal aspects of the hands and feet (“transgrediens”) and may overlie joints. Hyperhidrosis, superinfection, and occasionally perioral erythema, brachydactyly, and nail abnormalities are associated. Mal de Meleda is due to mutations in ARSB, which encodes SLURP-1.

The other choices represent gene defects for “non-transgrediens” forms of PPK (Plakoglobin in Naxos syndrome, TOC gene in Howel-Evans syndrome, K1 in non-epidermolytic PPK “Unna-Thost,” and K9 in epidermolytic PPK “Vorner.”

References: Perez C, Khachemoune A. Mal de Meleda: A Focused Review. Am J Clin Dermatol. 2016 Feb;17(1):63-70. [https://www.ncbi.nlm.nih.gov/pubmed/26445964]