CAJ | 학술논문

脆性X综合征是发生遗传性智力低下的主要原因之一,其分子基础被认为是由定位在染色体xq27.3的FMRl基因5'-UTR的(CGG)n动态突变所引起.仅仅当(CGG)n重复超过一定的界限(全突变)时,才表现出其临床表型.脆性X综合征复杂的分子遗传学病理机制和独特的遗传方式为其实验室诊断和遗传咨询带来了极大的困难.目前对于脆性X综合征的诊断,主要依赖于实验室检查.该文就细胞遗传学、Southern印迹杂交、聚合酶链反应(PCR)、RT-PCR和免疫组化分析等方法进行综述,以期更好的指导临床诊断和遗传咨询.
취성X종합정시발생유전성지력저하적주요원인지일,기분자기출피인위시유정위재염색체xq27.3적FMRl기인5'-UTR적(CGG)n동태돌변소인기.부부당(CGG)n중복초과일정적계한(전돌변)시,재표현출기림상표형.취성X종합정복잡적분자유전학병리궤제화독특적유전방식위기실험실진단화유전자순대래료겁대적곤난.목전대우취성X종합정적진단,주요의뢰우실험실검사.해문취세포유전학、Southern인적잡교、취합매련반응(PCR)、RT-PCR화면역조화분석등방법진행종술,이기경호적지도림상진단화유전자순.
Fragile X syndrome(FXS)is one of the most prevalent cause of inherited mental retardation.The underling molecular alteration consists of a CGG-repeat dynamic mutmion in the 5'untranslated region within the FMR1 gene,which is located in the telomeric region of the long arm of the X chromosome,Xq27.3.The phenotype is only apparent that the threshold in the number of repeats has been exceeded(full mutation).Its complex molecular genetics of pathogenesis and its unusual pattern of inheritance pose an extraordinary challenge for its diagnostic evaluation in the laboratory and for the genetic counseling of affected families.This review summarizes currently available procedures for the diagnostic evaluation of the FRAXA syndrome,including cytogenetic,Southern-blot,polymerase chain reaction(PCR),reverse transcription PCR(RT-PCR),and immunohistochemical analyses.