MBTPS2 and osteogenesis imperfecta: Prior to its association with OI, pathogenic missense variants in MBTPS2 were described in the dermatological spectrum condition Ichthyosis Follicularis, Atrichia, and Photophobia (IFAP, OMIM 308205) and Keratosis Follicularis Spinulosa Decalvans (KFSD, OMIM 308800) (Oeffner et al., 2009; Aten et al., 2010; Bornholdt et al., 2013).