Worsening of Callus Hyperplasia after Bisphosphonate Treatment in Type V Osteogenesis Imperfecta.

BACKGROUND Type V osteogenesis imperfecta is characterized by hyperplastic callus formation and interosseus membrane calcification. CASE CHARACTERISTICS A 16-year-old boy who presented with history of recurrent fractures, had hard persistent swellings at fracture sites, and had radiographic features of hyperplastic callus and interosseus membrane calcification. OUTCOME Sequence analysis of the IFITM5 gene revealed the c.-14 C>T mutation. The patient had significant exacerbation of callus hyperplasia after initiation of bisphosphonate therapy, which reversed following cessation of the treatment. MESSAGE Bisphosphonates may exacerbate callus hyperplasia, and may therefore have to be used with caution in patients with type V osteogenesis imperfecta.