摘要目的:总结1例 GNB1基因变异所致常染色体显性遗传性智力低下42型（MRD42）患儿的临床表型及遗传学特征，以提高对本病的认识。 方法:回顾性分析2023年3月郑州大学附属儿童医院神经内科确诊的1例 GNB1基因错义变异所致MRD42患儿的临床和遗传学资料，对患儿进行随访，对患儿资料进行总结，并复习既往相关文献。 结果:患儿为6月龄女童，主因“发育迟缓3个月，间断抽搐1个月”就诊。临床表现为全面性强直-阵挛发作、局灶性发作，智能低下，语言及运动发育迟缓；长程视频脑电图提示：背景活动慢，睡眠期双侧后头部棘波、棘慢波、多棘慢波、尖形慢波发放，3次局灶起始发作；头颅磁共振成像提示：双侧额颞部蛛网膜下腔略宽。染色体核型及拷贝数变异分析检查未见异常。全外显子测序结果显示 GNB1基因［NM_002074：c.155（exon5）G>A；p.Arg52Gln］新生杂合错义变异，此前未见相关文献报道。给予功能康复训练及抗癫痫发作药物治疗，癫痫发作得到有效控制。 结论:MRD42是一种罕见的由 GNB1基因变异导致的常染色体显性遗传性疾病，临床表现为婴儿期起病的癫痫发作、智力发育障碍、语言及运动发育迟缓等表型。 GNB1基因c.155G>A（p.Arg52Gln）新生杂合错义变异为本例先证者遗传学病因。

abstractsObjective:To summarize the clinical phenotype and genetic characteristics of a case of autosomal dominant mental retardation-42 (MRD42) caused by GNB1 gene mutation. Methods:The clinical and genetic data of a case of MRD42 caused by a GNB1 gene missense mutation diagnosed in the Department of Neurology, Children′s Hospital Affiliated to Zhengzhou University in March 2023 were retrospectively analyzed. The child was followed-up, the child′s data were summarized, and related literature was reviewed. Results:The patient is a 6-month-old female infant, who was admitted to hospital because of "developmental delay for 3 months, intermittent convulsions for 1 month". The clinical manifestations included generalized tonic-clonic seizures, focal seizures, intellectual disability, delayed language and motor development. Long-term video electroencephalogram showed slightly slower background activity, bilateral occipital spike and wave discharges, multispike and wave complexes during sleep. Three focal onset seizures were captured. Cranial magnetic resonance imaging suggested that the subarachnoid space of the bilateral frontotemporal areas was slightly wide. Chromosome karyotype and copy number variation analysis showed no abnormality. The results of whole exon sequencing showed a de novo heterozygous missense mutation in the GNB1 gene [NM_002074:c.155(exon5)G>A;p.Arg52Gln], which had not been reported. The seizure was effectively controlled by function rehabilitation training and anti-epileptic drug therapy. Conclusions:MRD42 is a rare autosomal dominant disorder caused by mutation in the GNB1 gene. The clinical manifestations include infantile-onset seizures, mental retardation, speech and motor development delay, etc. The de novo heterozygous missense mutation in the GNB1 gene c.155G>A(p.Arg52Gln) is the genetic cause of the proband.