Catatonia Associated With a SCN2A-Related Disorder in a 4-Year-Old Child.

Catatonia is a rare, underdiagnosed syndrome in children. We report the case of a 4-year-old child admitted for recent social withdrawal alternating with psychomotor excitement, verbigeration, and a loss of toilet readiness. He had a history of neonatal seizures, had been stabilized with vigabatrin, and was seizure free without treatment for several months. The pediatric and psychiatric examination revealed motor stereotypes, mannerism, bilateral mydriasis, and visual hallucinations. Laboratory and brain imaging explorations were initially negative. Catatonic symptoms, as measured with the Pediatric Catatonia Rating Scale, significantly decreased after introducing lorazepam, the first-line recommended treatment of this condition. On the basis of the neonatal seizure history, complementary genetic investigations were performed and revealed a mutation in the SCN2A gene, which encodes the voltage-gated sodium channel Nav1.2. Catatonic symptoms progressively disappeared after reintroducing vigabatrin. At the syndromic level, catatonia in young children appears responsive to high-dose lorazepam and is well monitored by using the Pediatric Catatonia Rating Scale. This case reveals the need for wide-ranging explorations in early-onset catatonia because specific targeted treatments might be available.