Rinsho Shinkeigaku (Clinical Neurology)

Case Report

A case of adult-onset type II citrullinemia with repeated nonconvulsive status epilepticus

Sayaka Funabe, M.D.1), Ryota Tanaka, M.D.1), Takao Urabe, M.D.1), Seiji Kawasaki, M.D.2), Keiko Kobayashi, M.D.3) and Nobutaka Hattori, M.D.1)

1)Department of Neurology, Juntendo University School of Medicine
2)Department of Hepatobiliary-Pancreatic Surgery, Juntendo University School of Medicine
3)Department of biochemistry, Faculty of Medicine, Kagoshima University

Adult-onset type II citrullinemia (CTLN2) is a hereditary metabolic disorder characterized by highly elevated plasma citrulline and ammonia. Recent studies have identified the "citrin gene" (SLC25A13) as the causative gene for CTLN2. Various neurobehavioral symptoms seen in this disease, such as unconsciousness, disorientation, abnormal behavior, and epilepsy, are thought to be caused by encephalopathy mostly due to hyperammonemia.
A 47-year-old woman presented with repeated unconsciousness and abnormal behavior. The high plasma anmonia level was not always associated with her neurobehavioral symptoms (unconsciousness, disorientation, abnormal behavior, and epilepsy), but paroxysmal EEG discharges were invariably associated with these symptoms. Her symptoms and abnormal EEG discharges were sometimes treated with diazepam simultaneously. Based on these findings, we considered that her symptoms were caused by nonconvulsive status epilepticus (NCSE).
Until date, neurobehavioral symptoms of CTLN2 are considered to be caused by hyperammonemia or other metabolic factors. We suggest that encephalopathy of CTLN2 is caused not only by hyperammonemia but also by NCSE. Therefore, repeated EEG monitoring is recommended in the follow up of patients with CTLN2.
Full Text of this Article in Japanese PDF (545K)

(CLINICA NEUROL, 49: 571|575, 2009)
key words: adult-onset type II citrullinemia, nonconvulsive status epilepticus, consciousness disturbance

(Received: 25-Nov-08)