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目的 探讨单分子荧光原位杂交(FISH)技术在诊断中国面肩肱型肌营养不良症(FSHD)患者的可行性.方法 采用单分子FISH技术对37例临床拟诊FSHD患者4qA区域的D4Z4重复单元数进行检测和分析.结果 35例明确诊断为FSHD患者4qA区域的D4Z4重复单元数介于2~7,平均值为(4.229±1.031).7例FSHD患者和2例临床拟诊FSHD患者的检测结果为:病例1、2、3来自同一个家系,为兄妹关系,4qA区域的D4Z4重复单元数分别为5、(6;32)和(5;32),片段长度分别为17.5 kb、(18.3;106.0) kb和(17.9;104.9) kb,D4Z4重复单元数在误差范围内,3例患者的变异可能遗传自其母亲;病例4的 4qA区域D4Z4重复单元数为(2;22),片段长度为(6.6;71.9) kb;病例5、6的4qA区域D4Z4重复单元数分别为4和5,片段长度分别为11.7 kb和17.3 kb;病例7为女性,55岁, 4qA区域D4Z4重复单元数为(5;68),片段长度为(18.1;224.0) kb,为本研究中年龄最大的女性患者;病例8、9为2例临床拟诊FSHD患者,4qA区域D4Z4重复单元数分别为(14;50)和33,片段长度为(44.6;164.8) kb和110.2 kb, 4qA区域的D4Z4重复单元数均>10.结论 FSHD患者存在高度家系间和家系内临床异质性.单分子FISH单次检测能同时准确分辨4种不同单倍型,即4qA、4qB、10qA和10qB的D4Z4重复单元数,可以明确检测致病相关的D4Z4单元重复数,误差在1 kb以内,能较精确地检测D4Z4单元重复数.因此,单分子FISH是现今精准的FSHD患者的临床分子诊断技术.“,”Aim To investigate the accuracy of single-molecular fluorescence in situ hybridization (FISH) in the genetic diagnosis of Chinese patients suspected of FSHD. Methods Single-molecular FISH was used to detect and analyze D4Z4 repeat units in 37 patients from China. Results The results showed that D4Z4 repeat units in the 4qA region of 35 confirmed FSHD patients was ranged from 2 to 7, with an average of (4.229±1.031). In 7 FSHD patients and 2 clinically suspected FSHD patients, case 1, 2, 3 were from the same family and were brothers and sisters. Their D4Z4 repeat units in 4qA region were 5, (6; 32) and (5; 32), respectively, and their D4Z4 fragment sizes were 17.5 kb, (18.3; 106.0) kb and (17.9; 104.9) kb, respectively. Their D4Z4 repeat units were likely be inherited from their mother. D4Z4 repeat units in 4qA region of case 4 was (2; 22), and the fragment size was (6.6; 71.9) kb. D4Z4 repeat units in 4qA region of case 5, 6 were 4 and 5, respectively, and the fragment sizes of them were 11.7 kb and 17.3 kb, respectively. Case 7 was a 55-year-old woman, who was the eldest female patient among this cohort. D4Z4 repeat units in 4qA region of case 7 was (5; 68), and the fragment size was (18.1; 224.0) kb. Cases 8 and 9 were 2 clinically suspected FSHD patients. Their D4Z4 repeat units in 4qA region were (14; 50) and 33, respectively, and the fragment sizes were (44.6; 164.8) kb and 110.2 kb, respectively. D4Z4 repeat units in the 4qA region of cases 8 and 9 were more than 10. Conclusion There was a high degree of inter- and intra-family clinical heterogeneity in patients with FSHD, and single-molecular FISH can accurately resolve D4Z4 repeat units of four different haplotypes, namely 4qA, 4qB, 10qA and 10qB. The results of single-molecular FISH can be used to detect accurately one D4Z4 repeat unit and 1 kb D4Z4 fragment sizes, which can greatly improve specificity and sensitivity. Therefore, single-molecular FISH currently can provide accurate moleular diagnostics for FSHD patients.