Five members of a Japanese family with a new form of spondylo-metaphyseal dysplasia (SMD) are reported. Another member was also probably affected. The disease was characterised by severe coxa vara, moderately severe metaphyseal changes of the long bones of the lower limbs, mild changes in the long bones of the upper limbs and grossly normal short tubular bones. Platyspondyly, present in the boys, was less marked in their father, whereas two affected aunts had normally shaped vertebral bodies.