Jacobs Julia, Bernard Geneviève, Andermann Eva, Dubeau François, Andermann Frederick
Montreal Neurological Institute and Hospital, Quebec, Canada.
Epileptic Disord. 2008 Dec;10(4):254-9. doi: 10.1684/epd.2008.0212.
The only consistent symptom of ring chromosome 20 syndrome (r(20)) is severe, refractory epilepsy often associated with a characteristic, although not pathognomonic, EEG pattern. Patients suffer from severe seizures with accompanying cognitive decline and frequent episodes of non-convulsive status epilepticus (SE). Other features of this rare disorder, such as dysmorphic changes, mental retardation and behavioral disturbances are variable. Because of the variability of the clinical presentation, some patients with r(20) undergo invasive investigations before being diagnosed.
We present the case of a young boy with no dysmorphic traits, who was only diagnosed with r (20) syndrome at the age of 13. His first seizure occurred at the age of four. Later seizures were of various types including non-convulsive SE, with deterioration of the background EEG and severe cognitive decline. Despite multiple trials of anti-epileptic medications, his seizures remained highly refractory, and he died as the result of an uncontrollable, prolonged SE, shortly after the diagnosis was made.
Non-convulsive SE is common in patients with r(20) syndrome and may be caused by a dysfunction in dopaminergic neurotransmission. However, until now, no case of lethal status epilepticus has been reported. This case report suggests that patients with unexplained refractory seizures and episodes of non-convulsive SE should undergo genetic testing early in their disease, even in the absence of any morphologic features or dysmorphic traits suggestive of a chromosomal disease.
20号环状染色体综合征（r(20)）唯一持续存在的症状是严重的难治性癫痫，常伴有特征性（虽非特异性）脑电图模式。患者遭受严重癫痫发作，伴有认知能力下降和频繁的非惊厥性癫痫持续状态（SE）发作。这种罕见疾病的其他特征，如畸形改变、智力障碍和行为障碍则各不相同。由于临床表现的多样性，一些r(20)患者在确诊前会接受侵入性检查。
我们报告一例无畸形特征的小男孩病例，他直到13岁才被诊断为r(20)综合征。他首次癫痫发作于4岁。后来的发作类型多样，包括非惊厥性SE，伴有背景脑电图恶化和严重认知能力下降。尽管多次尝试使用抗癫痫药物，他的癫痫发作仍高度难治，在确诊后不久，他因无法控制的长时间SE而死亡。
非惊厥性SE在r(20)综合征患者中很常见，可能由多巴胺能神经传递功能障碍引起。然而，迄今为止，尚未报道过致命性癫痫持续状态的病例。本病例报告表明，即使没有任何提示染色体疾病的形态学特征或畸形特征，对于不明原因的难治性癫痫发作和非惊厥性SE发作的患者，也应在疾病早期进行基因检测。
