Osteogenesis imperfecta-like syndrome with severe mental retardation and extrapyramidal tract signs.

We report a girl with a unique combination of malformations, including recurrent fractures, mental retardation with extrapyramidal tract signs and minor facial abnormalities. Generalised osteoporosis with overtubulation of long bones was similar to that of osteogenesis imperfecta (OI). However, the short tubular bones were distinctively undertubulated and wormian bones were not found. Based on clinical, laboratory and neuroradiological examinations, it was less likely that bone fragility was attributable to disuse bone atrophy related to her physical handicap and the neurological abnormalities secondary to brain insult. She is presumed to have a previously undescribed OI-like syndrome.