In 2007, clinical manifestation of GS was linked to mutations in PORCN [2, 3] encoding a 461 amino acid sized (52 kDa) protein named porcupine located to the Endoplasmic Reticulum (ER) and known to be involved in processing, secretion and signaling of Wnt proteins [4–6]. Here, PORCN is linked to Gerstmann syndrome.