Poon P M, Zhao Z, Wu X Q, Ni Y X, Pang C P
Department of Chemical Pathology, The Chinese University of Hong Kong, China.
Clin Chem Lab Med. 2000 Sep;38(9):935-8. doi: 10.1515/CCLM.2000.137.
The number of trinucleotide CGG repeats at the 5' untranslated region of the FMR1 gene is associated with the fragile X syndrome of mental retardation. We screened for the CGG repeat length in the FMR1 gene of the X-chromosomes from unrelated normal Chinese subjects recruited in Hong Kong and Dalian, a southern and a northern Chinese city respectively. These cities are about 3000 km apart and the residents have few historical interactions. Genomic DNA was analysed by PCR and detected by Southern hybridisation with a radiolabelled (CGG)5 probe for the CGG repeat number. A different distribution pattern of CGG allele size from the Caucasians is observed. It is a bimodal pattern with the most common CGG repeats allele at 29 against 30 in the Caucasians. Among the Hong Kong subjects, five alleles of more than 50 CGG repeats were detected, and four of those were in heterozygous females. There was no difference in the repeat patterns in subjects from the two cities, suggesting no genotypic variation in FMR1 between northern and southern Chinese.
FMR1基因5'非翻译区三核苷酸CGG重复序列的数量与脆性X智力低下综合征相关。我们对分别来自中国南方城市香港和北方城市大连的无关正常中国受试者的X染色体FMR1基因中的CGG重复长度进行了筛查。这两个城市相距约3000公里，居民之间几乎没有历史交流。通过PCR分析基因组DNA，并使用放射性标记的（CGG）5探针进行Southern杂交检测CGG重复数。观察到与白种人不同的CGG等位基因大小分布模式。这是一种双峰模式，最常见的CGG重复等位基因在中国人中是29，而在白种人中是30。在香港受试者中，检测到5个CGG重复超过50的等位基因，其中4个在杂合子女性中。来自两个城市的受试者的重复模式没有差异，表明中国北方人和南方人FMR1基因的基因型没有差异。
