Vertebral arch nonfusion and juvenile myoclonic epilepsy.

Neural tube defects (NTD) are known to occur at a higher rate in pregnancies of women with epilepsy. Antiepileptic drugs (AEDs), notably valproate (VPA) and carbamazepine (CBZ), have been identified as risk factors, but a familial aggregation of this condition also occurs in the absence of pharmacologic teratogens. Spina bifida occulta, defined as a nonsymptomatic nonfusion of vertebral arches, has been suggested to be genetically determined, with an increased prevalence in patients with primary generalized epilepsy, and that the presence of this trait in fetal development can be enhanced pharmacologically to produce NTD such as meningomyelocele. In this study, plain abdominal radiographs were obtained from 56 patients with juvenile myoclonic epilepsy (JME) and 56 age- and sex-matched controls. The radiographs were presented in a random order to an unbiased radiologist. No difference in prevalence of vertebral arch nonfusion (VAN) was noted between the two groups. Even if it has no increased frequency in patients with epilepsy, however, VAN is a common radiologic finding, and its relation to symptomatic neural tube defects should be clarified in future studies.