摘要目的：分析Angelman 综合征( AS)的基因型和表型之间的关联,并探讨单核苷酸多态性比较基因组杂交技术( SNP aCGH)对AS诊断的价值。方法将11例临床诊断AS的患儿分别行脑电图检查、格赛尔( Gesell)评分,予甲基化聚合酶链反应初筛,再予SNP aCGH全基因组扫描,获得染色体异常拷贝数据并分析。结果(1)11例患儿遗传诊断为AS,缺失型10例(其中Ⅱ型缺失6例,I型缺失4例),单亲二倍体(UPD)1例。(2)15q11-q13为染色体异常拷贝区域,根据其起始范围,查阅人类孟德尔遗传在线基因库(OMIM),明确缺失片段中主要包括以下基因：MKRN3、MAGEL2、NDN、SNRPN、SNURF、GABRB3、GABRA5、GABRG3、UBE3A、OCA2、ATP10A。(3)缺失型患儿身高及体质量较健康同龄儿低3~5个标准差,UPD患儿身高及体质量低于健康同龄儿约1.5个标准差。 Gesell评估显示Ⅰ型缺失为重度、极重度智力残疾；Ⅱ型缺失为中度智力残疾；UPD患儿为轻度智力残疾。发现色素沉着障碍共8例,包括UPD患儿。1例Ⅰ型缺失和UPD患儿脑电图提示偶发棘波,另1例Ⅰ型缺失,为界限性脑电图,其余患儿为阵发性中高波幅的棘波、慢波、棘慢波(2.5~3.0 Hz)。结论SNP aCGH技术在确诊AS的同时能明确基因病理分型,检出染色体拷贝数异常区域的起始点所在,明确缺失片段大小及片段中所涉及的基因,利于表型和基因型的关联分析,提供针对性的遗传咨询,且为AS发病机制、基因功能定性等研究提供一个良好的技术平台。

abstractsObjective To analyze the genotype-phenotype correlations of Angelman syndrome ( AS ) , and to discuss the advantage of applying array-based single nucleotide polymorphisms comparative genomic hybridization ( SNP aCGH) in diagnosis of AS. Methods Examination of electroencephalogram( EEG) and intelligence quotient( IQ) evaluation were done for 11 cases diagnosed as AS clinically. Gesell scares were chosen as the evaluation criterion of IQ. The screening techniques was methylation polymerase chain reaction( MS-PCR) ,then SNP aCGH was used to make genetic diagnosis. Results (1)Eleven cases of AS were confirmed:1 case had UPD(uniparental disomy),10 cases were type of deletion, from which 6 cases were deletion (Ⅱ) , 4 cases were deletion (Ⅰ) . ( 2 ) The copy number variations were detected in the region of 15q11-q13,which contained genes like MKRN3,MAGEL2,NDN,SNRPN, SNURF,GABRB3,GABRA5,GABRG3,UBE3A,OCA2,ATP10A. To search online Mendelian inheritance in man,genes above were correlated with AS manifestation. (3)All cases of deletion were 3-5 standard deviation(SD) in weight and height to normal children at the same age and with the same sex,while UPD was below 1. 5 SD. Gesell scares showed that the deletion(Ⅰ) was the most serious in mental retardation,deletion(Ⅱ) was moderate,and the UPD was mild. Eight cases were hypopigmentation,and one was the UPD. EEG revealed that 1 case of deletion(Ⅰ) and the UPD were spike occasionally,another one deletion(Ⅰ) was limit EEG. The rest cases displayed slow and spike waves paroxysmal-ly,with amplitude of medium or high,2. 5-3. 0 Hz. Conclusions Not only can SNP aCGH make a diagnosis of AS but discriminate the types of genetic pathology. Since different type contributes to a diverse of clinical features and the rate of recurrence is also different,it is significant for family genetic consultation. Moreover,the technology is advantageous for the study on the pathogenesis and gene function.