Tarleton J, Wong S, Heitz D, Schwartz C
Greenwood Genetic Center, DNA Diagnostic Laboratory, South Carolina 29646.
J Med Genet. 1992 Oct;29(10):726-9. doi: 10.1136/jmg.29.10.726.
Genetic recombination near the fragile X locus (Xq27.3) has frequently been a problem in linkage studies of families in which the fragile X is segregating. This case report illustrates the resolution of a difficult situation in a fragile X family for whom cytogenetic studies were inconclusive and where recombination had twice confounded attempts at prenatal DNA diagnosis by RFLP analysis. Using a newly developed DNA probe, StB12.3, for direct detection of DNA instability in the fragile X locus, the presence of the fragile X was ascertained definitively in a prenatal DNA sample.
在脆性X染色体（Xq27.3）附近发生的基因重组，在脆性X染色体进行分离的家系连锁研究中常常成为一个问题。本病例报告阐述了一个脆性X家系中疑难情况的解决过程，该家系的细胞遗传学研究结果不明确，并且重组曾两次干扰通过限制性片段长度多态性（RFLP）分析进行的产前DNA诊断尝试。使用一种新开发的DNA探针StB12.3直接检测脆性X位点的DNA不稳定性，最终在一份产前DNA样本中明确确定了脆性X染色体的存在。
