散发Rett综合征患儿新生MECP2突变亲源鉴定和X染色体失活15例分析

Objective Rett syndrome (RTT) is a neurodevelopmental disorder occurring almost exclusively in females as sporadic cases due to de novo mutations in the methyl-CpG-binding protein 2 gene ( MECP2 ). Familial cases of RTT are rare and are due to X-chromosomal inheritance from a cartier mother. Recently, DNA mutations in the MECP2 have been detected in approximately 84.7% of patients with RTT in China. To explain the sex-limited expression of RTT, it has been suggested that de novo X-linked mutations oecttr exclusively in male germ cells resulting therefore only in affected daughters. To test this hypothesis, we have analyzed the parental origin of mutations and the XCI status in 15 sporadic cases with RTT due to MECP2 molecular defects. Methods Allele-specific PCR was performed to amplify a fragment including the position of the mutation. The allele-specific PCR products were sequenced to determine which haplotype contained the mutation. It was then possible to determine the parent of origin by genotyping the single nucleotide polymorphism (SNP) in the parents. The degree of XCI and its direction relative to the X chromosome parent of origin were measured in DNA prepared from peripheral blood leucocytes by analyzing CAG repeat polymorphism in the androgen receptor gene (AR). Results Except for 2 cases who had a frameshifi mutation; all the remaining 13 cases had a C→T transition mutation. Paternal origin has been determined in all cases with the C→T transition mutation. For the two frameshift mutations, paternal origin has been determined in one case and maternal origin in the other. The frequency of male germ-line transmission in mutations is 93.3%. Except for 2 cases who were homozygotic at the AR locus, of the remaining 13 cases, 8 cases had a random XCI pattern; the other five cases had a skewed XCI pattern and they favor expression of the maternal origin allele. Conclusion De novo mutations in sporadic RTr occur almost exclusively on the paternally derived X chromosome and that this is most probably the cause for the high female: male ratio observed in sporadic cases with RTT. Random XCI was the main XCI pattern in sporadic RTT patients. The priority inactive X chromosome was mainly of paternal origin.     

风寒湿热环境对胶原诱导性关节炎大鼠模型中医证型的影响

目的 研究人工风寒湿热因素对胶原诱导性关节炎（CIA）大鼠模型中医证型的影响，探讨风寒湿热环境的致病实质。 方法 24 只 SPF 级雌性 SD 大鼠按随机数字表法分为空白对照（BC）组、风寒湿环境（FHS）组、风湿热环境（FSR）组，阴性对照（NC）组，每组 6 只，除 NC 组外，对其余 3 组进行 CIA 造模，造模成功后进行人工气候箱干预，BC 组与 NC 组置于 SPF 环境中、FHS 组接受人工 FHS 环境干预、FSR 组接受人工 FSR 环境干预，每天 2 次，每次 2 h，连续干预 14 天。 观察测量各组在实验过程中关节炎指数（AI），人工气候箱干预结束后进行双踝关节皮肤红色值（a 值）、双踝关节 X 线、血清缺氧诱导因子 1α（HIF1α）与热休克蛋白 70（HSP70）、关节组织病理及免疫组化等检测。 结果 与 BC 组比较，FSR 组 AI 值更快达到峰值、峰值维持时间长、下降幅度慢（P<0.05），FHS 组 AI 值与之相反（P>0.05）；FSR 组 a 值、X 线评分、血清及滑膜组织 HSP70 含量均高于 BC 组（P<0.01），FHS 组血清及滑膜组织 HSP70 含量低于 BC 组（P<0.05）；4 组大鼠血清及滑膜组织不表达 HIF1α，差异均无统计学意义（P>0.05）；踝关节病理提示 3 组 CIA 大鼠细胞增生以炎症细胞为主，FHS 组大鼠病理评分较 BC 组低（P<0.05），FSR 组大鼠病理血管翳增生明显、骨质破坏较严重，病理评分较 BC 组高（P<0.05）。 结论 风寒湿热环境刺激能影响 CIA 大鼠模型的中医证候；CIA大鼠基础属性为热，经 FSR 刺激后具有显著的热痹证候演变过程，可作为热痹模型，其实质与 HSP70 上调有关；经 FHS 刺激后并未表现寒痹证候特点，不能作为寒痹模型，其致病实质尚需进一步探讨。