Congenital fusion of cervical vertebrae: a review on embryological etiology

Congenital fusion of cervical vertebrae is a rare anomaly. In this condition, two fused vertebrae appear structurally and functionally as one. This anomaly may be symptomatic or asymptomatic. Myelopathy, limitation in neck movement, muscular atrophy and regional sensory loss are examples of probable morbidity associated with this anomaly. Combination of genetic and environmental factors are involved in pathogenesis of this anomaly. Malformation of notochord, poor performance of retinoids, decreased local blood supply of spine and alteration in genes expression, especially members of Hox and Pax family genes are some of the proposed reasons of congenital fusion of cervical vertebrae. Diagnosis of this congenital anomaly in childhood seems to have an important role in prevention of probable secondary disorders in adulthood. We offer to clinicians that after performing careful physical tests and noticing the presence of signs and symptoms that mentioned in this paper, if a patient suspected to have congenital fusion of cervical vertebrae, genetic tests ought to be performed.