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Martin-Bell综合征(MBS)是一种常见的X连锁遗传病,它与X染色体q27.3脆性位点有关,且伴有不同程度智力缺陷和体征。MBS的临床和细胞遗传学表现差异很大,所以对此病的遗传分析较为困难。在缺少系谱资料情况下,只有检查fra(X)染色体,才能确定携带者。由于近70%的女性携带者和20%的男性半合子,没有明显的临床或细胞遗传异常,所以,即使未检出细胞遗传异常,也不能定论;完整家系中的细胞遗传资料与fra(X)位点紧密连锁的DNA标记结合运用,使得估计风险中的fra(X)阴性个体携带者的概率成为可能。但,此概率可能
Martin-Bell Syndrome (MBS) is a common X-linked genetic disease that is associated with the q27.3 fragile site of the X chromosome and is associated with varying degrees of mental retardation and signs. The clinical and cytogenetic manifestations of MBS vary greatly, so genetic analysis of the disease is more difficult. In the absence of pedigree information, only the fra (X) chromosome can be examined to determine the carrier. Since nearly 70% of female carriers and 20% of male hemizygotes have no obvious clinical or cytogenetic abnormalities, it is inconclusive even if no cytogenetic abnormalities have been detected; cytogenetic data in intact pedigrees and fra (X ) Locus tightly linked DNA markers make it possible to estimate the probability of fra (X) negative individuals at risk. However, this probability is possible