COL1A2 and osteogenesis imperfecta: Moreover, accumulating evidence shows an association between mutations in genes encoding proteins involved in type I procollagen processing or chaperoning and pathogenesis of recessive variants of osteogenesis imperfecta (OI), while dysregulation of molecular chaperones is implicated in ER stress in severe forms of osteoarthritis (OA) (Lisse et al. 2008; Kelley et al. 2011; Marini et al. 2010; Bodian et al. 2009; Symoens et al. 2013; Nugent et al. 2009; Takada et al. 2011).