FKBP10 and osteogenesis imperfecta: It has been previously suggested that mutations in the chaperone protein FKBP10 could be responsible for OI type VI (MIM #610968); this was based upon a focal abnormal lamellar pattern that was observed in a single bone biopsy sample from a severe OI patient carrying a mutation in this gene.12 However, no mutations in FKBP10 were identified in our patient cohort that was classified based on the diagnostic requirement for OI type VI of having an excess of unmineralized osteoid tissue, indicative of a mineralization defect in addition to a fish-scale pattern in their bone matrix.