Inadequate PAX-1 gene expression as a cause of agenesis of the thoracolumbar spine with failure of segmentation

Abstract

✓ U An unusual case with absence and “fusion” of several thoracic and lumbar vertebral bodies leading to a severe thoracolumbar kyphos is presented. Late-onset neurological deterioration occurred due to spinal cord compression, which was treated with anterior decompression. Although several mechanisms for the development of these extensive and rare abnormalities have been proposed, the cause in humans remains unknown. An embryological basis is presented in the light of recent advances in molecular genetics, which show that abnormal notochordal signals and Pax-1 gene expression can produce an experimental phenotype very similar to the one in the patient described here. Thus it is suggested that faults in these early developmental processes may be, at least in part, responsible for the development of such extensive anomalies.