Focal dermal hypoplasia (FDH), also known as Goltz syndrome, is an X-linked dominant disorder that features Blaschko linear streaks of skin with a markedly thinned dermis (and adipose tissue abutting the epidermis) together with ocular, dental, and skeletal abnormalities. In 2007, loss-of-function mutations in the PORCN gene (OMIM 300651) were found to cause FDH.1,2PORCN, a member of the porcupine gene family, encodes a putative O-acyltransferase that facilitates Wnt protein secretion from the endoplasmic reticulum. As important regulators of embryonic development, Wnt proteins promote fibroblast proliferation, inhibit adipogenesis, and induce osteogenesis.
Schaffer JV, Cantatore-Francis JL, Shin HT, Rosenman KS. Syringocystadenoma Papilliferum in a Patient With Focal Dermal Hypoplasia Due to a Novel PORCN Mutation. Arch Dermatol. 2009;145(2):218–219. doi:10.1001/archdermatol.2008.569