Therman E, Denniston C, Sarto G E, Ulber M
Hum Genet. 1980;54(2):133-43. doi: 10.1007/BF00278961.
The correlations of abnormal X chromosome constitutions and the resulting phenotypes in the human female are reviewed. The following hypotheses put forward to explain these correlations are discussed in detail: (1) The damage is done before X inactivation; (2) An effect is exerted between reactivation of the X chromosome(s) and meiosis in oocytes; (3) A recessive gene(s) in hemizygous condition might be expressed in the cases in which the same X is active in all cells; (4) A change in the number of presumed active regions on the inactive X chromosomes might have an effect; (5) A position effect, in that the region Xq13-q27 has to be intact in both X chromosomes to allow normal development, may be responsible; (6) An effect during the period when cells with different inactivation patterns compete is a probability; (7) The original X inactivation may be neither regular nor random. The conclusion reached is that the phenotypic effects of a specific X chromosome aberration may be simultaneously exerted through different pathways (Tables 1 and 2). Hypotheses (2), (4), (5), and (6) are considered probable. Hypothesis (3) has been discarded, and there is very little evidence for hypotheses (1) and (7).
本文综述了人类女性异常X染色体构成与其所产生表型之间的相关性。详细讨论了为解释这些相关性而提出的以下假设：（1）损伤发生在X染色体失活之前；（2）X染色体重新激活与卵母细胞减数分裂之间存在影响；（3）在所有细胞中同一X染色体处于活性状态的情况下，半合子状态下的隐性基因可能会表达；（4）失活X染色体上假定的活性区域数量变化可能会产生影响；（5）位置效应可能起作用，即两条X染色体上的Xq13-q27区域都必须完整才能实现正常发育；（6）不同失活模式的细胞相互竞争期间产生影响是有可能的；（7）最初的X染色体失活可能既不规则也不随机。得出的结论是，特定X染色体畸变的表型效应可能通过不同途径同时发挥作用（表1和表2）。假设（2）、（4）、（5）和（6）被认为是有可能的。假设（3）已被摒弃，而假设（1）和（7）几乎没有证据支持。
