Congenital vertebral anomalies: aetiology and relationship to spina bifida cystica.

A family survey of 337 patients with congenital vertebral anomalies has been carried out from the Scoliosis Clinics of Edinburgh and the Royal National Orthopaedic Hospital, London. From genetic and epidemiological evidence it is clear that multiple vertebral anomalies (without apparent spina bifida) are aetiologically related to anencephaly and spina bifida cystics, carrying a 5-10% risk to subsequent sibs for any one of these defects. The implications for prenatal diagnosis are discussed. Solitary hemivertebrae and localized anterior defects of the vertebral bodies causing kyphoscoliosis are sporadic (non-familial) in nature, carrying no risk to subsequent sibs.