Friedman J M, Howard-Peebles P N
Am J Med Genet. 1986 Jan-Feb;23(1-2):701-13. doi: 10.1002/ajmg.1320230161.
The fragile X (fra(X), or Martin Bell-MB) syndrome is considered an X-linked recessive trait. However, clinically normal male transmitters of the condition have been observed occasionally. The occurrence of "carrier" males and the observation of other unusual genetic characteristics in the MBS suggest that this condition is not a standard X-linked recessive trait. We propose that the MBS is due to a transposable genetic element which can exist in 3 different chromosomal states and effect 2 different extrachromosomal environments. This model can account for the peculiar genetic behavior of the fragile X syndrome.
脆性X综合征（fra(X)，或马丁-贝尔综合征-MB）被认为是一种X连锁隐性性状。然而，偶尔也观察到患有这种疾病的临床正常男性携带者。“携带者”男性的出现以及马丁-贝尔综合征中其他异常遗传特征的观察表明，这种疾病并非典型的X连锁隐性性状。我们提出，马丁-贝尔综合征是由一种可转座的遗传元件引起的，该元件可存在于3种不同的染色体状态，并影响2种不同的染色体外环境。这个模型可以解释脆性X综合征独特的遗传行为。
