Neonatal hypocalcemic seizures in siblings exposed to topiramate in utero.

We describe two siblings with neonatal hypocalcemic seizures whose mother took topiramate during both pregnancies. Apart from hypocalcemia, the patients had no identifiable etiology for their seizures. Although biochemical data suggested that the hypocalcemia was caused by hypoparathyroidism, no disorders typically associated with this condition were identified in the patients. We propose that topiramate exposure in utero led to hypoparathyroidism and subsequent hypocalcemia via effects on protein kinase A signaling, resulting in hypocalcemic seizures. Neonates exposed to topiramate in utero should be monitored for hypocalcemic seizures.