葡萄胎中CDKN2A基因纯合性缺失和突变的研究

Detection of Homozygous Deletions and Mutations of the CDKN2A Gene in Hydatidiform Moles

目的:探讨细胞周期依赖性激酶抑制基因(CDKN2A基因,包括p16INK4a和p14ARF基因)外显子1、2的纯合性缺失和突变情况与葡萄胎发生的关系。方法:对38例葡萄胎和30例早孕绒毛的新鲜组织标本进行基因组DNA抽提、PCR扩增,而后应用变性高效液相色谱分析(DHPLC)的方法对扩增产物进行突变检测。结果:1)38例葡萄胎组织样本中,5例发生p16INK4a基因外显子1的纯合性缺失,其纯合性缺失率为13.16%;而30例早孕绒毛组织标本中,未发现p16INK4a基因外显子1的纯合性缺失。p16INK4a外显子1的纯合性缺失率在早孕绒毛组织和葡萄胎组织中差异具有统计学意义(P=0.036);2)38例葡萄胎组织样本和30例早孕绒毛组织样本中,无一例发生p14ARF基因外显子1和p16INK4a外显子2的纯合性缺失;3)经DHPLC检测,38例葡萄胎组织样本和30例早孕绒毛组织样本中,p16INK4a基因外显子1、2和p14ARF基因外显子1扩增产物的所有谱图均为单一峰型,未检测到任何位点的突变发生。结论:p16INK4a基因外显子1的纯合性缺失与葡萄胎的发生具有一定的相关性;在葡萄胎中,CDKN2A基因的遗传变异主要是由于此基因的纯合性缺失造成的,突变可能不是此基因变异的主要形式。

Objective： To investigate homozygous deletion and mutation of the CDKN2A gene （pl6INK4a and pl4ARF gene） in 38 hydatidiform mole patients and 30 early pregnancy patients. Methods： A total of 38 hydatidiform mole and 30 early pregnancy villi samples were assessed for homozygous deletion of the CDKN2A gene by polymerase chain reaction （PCR）, and mutations were detected using degenerative high performance liquid chromatography （DHPLC）. Results： （1） Among the 38 hydatidiform mole samples, homozygous deletions of p16^INK4a exon 1 were identified in 5 eases （13.16%）. However, no homozygous deletions of p16^INK4a exon 1 were found in the 30 early pregnancy samples. A significant difference was found in the rate of homozygous deletion of p16^INK4a exon 1 between hydatidiform mole and early pregnancy villi samples（P=0.036）. （2） No homozygous deletions of pl4ARF exon 1 and p16^INK4a exon 2 were found in any of the 38 hydatidiform mole samples or the 30 early pregnancy samples. （3） In all samples, all PCR amplification products of p14^ARF exon 1 and p16^INK4a exon 1 and 2 produced single peak curves when detected by DHPLC, suggesting an absence of mutations. Conclusion： There is probably a close correlation between the homozygous deletion of CDKN2A and the occurrence of hydatidiform mole.