三个Rb基因突变嵌合体家系分子遗传学分析

目的：遗传型RB是一种单基因疾病，由定位在13q14的Rb基因突变所致。大多数遗传性RB表现出典型的孟德尔常染色体显性遗传特征。作者分析三个遗传性RB家系RB外显不全及表型传递规律变异的原因。方法：RELPs和VNTRs作单体型分析，SSCP及直接DNA序列分析检测Rb基因点突变。结果：Rb基因突充嵌合体是造成某些Rb基因突变携带者不发病以及家庭成员中RB表型遗传不符合孟德尔规则的重要原因之一。结论：直接检测致病性的Rb基因突变才能准确判断携带者，估计患病风险。（中华眼底病杂志，1996，12：37-40）

THREE MOSAICISMS FOR RETINOBLASTOMA GENE POINT MUTATION

OBJECTIVE:The hereditary form of retinoblastoma(RB)is a monogenic disorder which is due to germinal mutation of RB susceptibility gene located on 13q14.The majority of hereditary RB cases transmit as a Mendelian autosomal dominant inheritance that 50% of the offspring of a carrier will inherit the disorder susceptibility gene and all carriers will develop the disorder.The authors report 3 hereditary RB families with incompleted penetrance and irregular transmission of RB phenotype.METHOD:RFLPs&;VNTRs for analysis of haplotype and SSCP&;direct DNA sequencing for determination of RB point mutation.RESULTS:The mosaicism of Rb gene point mutation resulted in the incompleted penetrance and irregular transmission of RB phentype.CONCLUSION:DAN-based diagnosis can be used to differentiate the hereditary and nonhereditary forms of retinblastoma but only is the direct detection of disease-causing mutation reliable for determnation of carrier and estimation of th e risk for retinoblastoma.（Chin J Ocul Fundus Dis,1996,12: 37- 40）