The PORCN gene consists of 15 exons and it encodes an endoplasmic reticulum transmembrane protein known as protein-serine O-palmitoleoyltransferase porcupine, which belongs to the evolutionarily conserved porcupine (Porc) family. PORCN gene product plays a key role in the regulation of Wnt signalling pathway by mediating the palmitoylation of WNT proteins. Loss of function mutations in the PORCN gene interferes with the normal functioning of Wnt signalling pathway, consequently disrupting the downstream processes that are controlled by WNT proteins such as body-axis patterning, cell proliferation, cell migration and other cell responses. Variations in PORCN gene are associated with focal dermal hypoplasia, where it is believed to affect the normal dermal tissue development in patients. In addition, mutation in PORCN gene is also known to be involved in Wnt-driven tumorigenesis.