Osteogenesis imperfecta type II in one of a pair of twins.

variety of biochemical defects in type I procollagen resulting in disruption of triple helical conformation and procollagen suicide are responsible for the clinical features(2). Some cases are autosomal recessivtf but many are new dominant mutations. A large majority of patients die in early neonatal period or infancy but the incidence in general population is kept constant as a result of new mutations. It has been estimated that the mutation rate in osteogenesis imperfecta is 4 x 10 per gene per generation(3). The occurrence of osteogenesis imperfecta in one of a pair of twins would be a rare chance association. On extensive review of literature we could come across only two such reports(4,5). The purpose of this communication is to describe our experience of such a case, emphasize the inclusion of long bone evaluation in the 'routine' antenatal ultrasound examination and raise the management dilemma posed by such a situation.