Smith-Magenis综合征一例临床及遗传学研究

Clinical and genetic study of a case with Smith-Magenis syndrome

目的 分析1例Smith-Magenis综合征患儿的临床特征及基因诊断情况.方法 分析患儿面部特征、体格和智力发育状况.实验室检查采用常规和高分辨G显带分析患儿及父母外周血染色体核型、比较基因组杂交芯片（array comparative genomic hybridization,array CGH）检测微小染色体改变,荧光定量PCR验证芯片结果.结果 患儿女,2岁,因发育落后和先天性心脏病就诊.平日入睡困难,睡眠周期短.动作多,有撞头等自我伤害行为.体检见面容特殊：发际低,前额突出,面部平,低鼻梁,嘴角向下,上唇轻度外翻,耳位低,腭弓高.Gesell发育测试显示中度发育落后.心脏彩超显示室间隔缺损、房间隔缺损、主动脉骑跨、肺动脉高压.头颅核磁共振显示脑室大、脑沟深.常规染色体核型为46,XX,高分辨染色体核型分析17号染色体短臂疑似缺失,比较基因组杂交芯片分析显示该患儿17p11.2缺失,缺失片段为3.8 Mb,分子核型为46,XX.arr17p11.2（16543655-20374751）×1 dn.父母核型正常.结论 Smith-Magenis综合征主要表现生长发育落后和精神发育迟滞,特殊面容,睡眠障碍,行为异常等临床特征,比较基因组杂交芯片检测明确其分子病因为17p11.2缺失.

Objective To explore the clinical feature and genetic diagnosis for Smith-Magenis syndrome （SMS）.Method The clinical data,including craniofacial anomalies,physical and mental status were analyzed.Routine and high resolution G-banding was performed to analyze the karyotype of the patient and her parents,and array comparative genomic hybridization （array CGH ） was used to detect small chromosome anomaly.Result A-two-year old girl was sent to our clinic for mental retardation and cardiac malformation.Some sleep problems were reported by parents,including difficulties falling asleep,shortened sleep cycles. She also had some neurobehavioral symptoms including hyperactivity and self-injurious behaviors head-banging.She had distinctive craniofacial features including low hairline,frontal bossing,a broad face,broad nasal bridge,a tented upper lip,prognathism,low-set ears and high-vaulted arch.She had moderate mental retardation.Cardiac findings included ventricular septal defect,atrial septal defect,overriding aorta and pulmonary hypertension. Primary ventriculomegaly was seen in magnetic resonance imaging （MRI）. Routine karyotype analysis showed a karyotype of 46,XX. However,high resolution karyotype analysis showed a suspected partial deletion of the short arm of chromosome 17.Array comparative genomic hybridization （ array CGH ） finely mapped the deletion to a 3.8 Mb region on 17p11.2.The molecular karyotype was then ascertained as 46,XX.arr17p1 1.2 （ 16543655-20374751 ） × 1 dn.The parents had normal karyotypes. Conclusion Smith-Magenis syndrome is a multisystem disorder characterized by developmental delay and mental retardation, distinctive craniofacial features, sleep disturbance and behavioral problems.Array comparative genomic hybridization （array CGH） finely mapped the deletion on 17p11.2.