To describe the phenotypic spectrum in patients with MBD5-associated neurodevelopmental disorder (MAND) and seizures; features of MAND include intellectual disability, epilepsy, psychiatric features of aggression and hyperactivity, and dysmorphic features including short stature and microcephaly, sleep disturbance, and ataxia.

We performed phenotyping on patients with MBD5 deletions, duplications, or point mutations and a history of seizures.

Twenty-three patients with MAND and seizures were included. Median seizure onset age was 2.9 years (range 3 days–13 years). The most common seizure type was generalized tonic-clonic; focal, atypical absence, tonic, drop attacks, and myoclonic seizures occurred frequently. Seven children had convulsive status epilepticus and 3 nonconvulsive status epilepticus. Fever, viral illnesses, and hot weather provoked seizures. EEG studies in 17/21 patients were abnormal, typically showing slow generalized spike-wave and background slowing. Nine had drug-resistant epilepsy, although 3 eventually became seizure-free. All but one had moderate-to-severe developmental impairment. Epilepsy syndromes included Lennox-Gastaut syndrome, myoclonic-atonic epilepsy, and infantile spasms syndrome. Behavioral problems in 20/23 included aggression, self-injurious behavior, and sleep disturbance.

MBD5 disruption may be associated with severe early childhood-onset developmental and epileptic encephalopathy. Because neuropsychiatric dysfunction is common and severe, it should be an important focus of clinical management.

描述 MBD5 相关神经发育障碍 (MAND) 和癫痫患者的表型谱；MAND 的特征包括智力障碍、癫痫、攻击性和多动的精神病学特征，以及畸形特征，包括身材矮小和小头畸形、睡眠障碍和共济失调。

我们对有MBD5缺失、重复或点突变且有癫痫病史的患者进行表型分析。

包括 23 名患有 MAND 和癫痫发作的患者。中位癫痫发作年龄为 2.9 岁（范围 3 天至 13 岁）。最常见的癫痫发作类型是全身强直阵挛；局灶性、非典型失神、强直、跌倒发作和肌阵挛发作频繁发生。7名儿童有惊厥性癫痫持续状态和3名非惊厥性癫痫持续状态。发烧、病毒性疾病和炎热的天气引发了癫痫发作。17/21 患者的脑电图研究异常，通常显示缓慢的全身棘波和背景减慢。9 人患有耐药性癫痫，但 3 人最终没有癫痫发作。除一名外，其他所有人都有中度至重度发育障碍。癫痫综合征包括 Lennox-Gastaut 综合征、肌阵挛-失张力性癫痫和婴儿痉挛综合征。20/23 的行为问题包括攻击性、自残行为、

MBD5破坏可能与严重的儿童早期发病的发育性和癫痫性脑病有关。由于神经精神功能障碍常见且严重，应成为临床管理的重点。