Prader-Willi综合征1例患者细胞及分子遗传学分析

Cytogenetic and molecular analysis of a case of Prader-Willi syndrome

目的:探讨特殊类型第二性征发育不良的细胞及分子遗传学诊断的意义及各种检测方法的适用性.方法:采用染色体核型分析、比较基因组杂交、多重连接探针扩增及甲基化特异性PCR对1例第二性征发育不良患者进行诊断与鉴别诊断. 结果:患者核型分析结果为46,XY;SRY及AZF基因检测未发现异常;初检用Sure-Print G3Human CGH Array Kit8 ×60K芯片未发现染色体重复和缺失,复检用SurePrint G3 unrestricted CGH ISCA v2,8 ×60K芯片发现15号染色体存在约68.9 kb缺失(hg19:25190737-25259677);多重连接探针扩增技术检测分析发现SNRPN基因外显子3存在缺失;甲基化特异性PCR检测分析发现患者样本与对照样本母源片段信号未见差异,而患者父源片段信号明显降低. 结论:经过多种检测技术并结合临床,最终该患者确诊为Prader-Willi综合征.

Objective:To investigate the significance of cytogenetic and molecular genetic diagnosis of a special type of secondary sexual dysplasia and the applicability of various methods for its detection.M ethods:Using karyotype analysis,array comparative genomic hybridization(aCGH),multiplex ligation-dependent probe amplification(MLPA)and methylation-specific PCR(MS-PCR),we diagnosed and differentially diagnosed a case of secondary sexual dysplasia.Results:Abnonnalities were not found in the karyotype analysis or the SRY and AZF gene detection,nor chromosomal duplication and deletion in the initial SurePrint G3 Human CGH Array Kit8 × 60K.SurePrint G3 unrestricteda CGH ISCA v2,88 x60K,however,identified a 68.9 kb deletion of chromosome 15(hgl9:25190737-25259677).MLPA revealed the deletion of exon 3 of the SNRPN gene.MS-PCR showed a significant decrease in the paternal fragment signals,but no difference in the maternal fragment signals between the sample from the patient and that from the control.Conclusion:The patient was confirmed with Prader-Willi syndrome by various methods of detection.