SCN4A and Kyphosis: During the course of our studies, another model of kyphosis designated Skm1, due to an Ile384Asn NPR3 mutation was reported [28] (Table 2); however the Asn384 mutation does not introduce a consensus N-linked glycosylation site, similarly to the Eel NPR3 mutation, and thus is likely to be retained in the ER but without abnormal N-linked glycosylation.