应用不同模型分析X染色体失活机制

X染色体失活（XCI）假说的提出,引起了很多研究学者对XCI机制的不断探索,特别是X失活中心（XIC）的深入研究,不同的学者提出了不同的X染色体失活模型来对实验数据进行解释。目前主要的模型有：阻断因子模型,双因子模型,传感选择模型,随机模型和反馈模型。这些模型的提出,使得X染色体失活机制不断得到完善,相信随着研究的深入,X染色体失活机制必将得到揭示。     

X染色体倾斜失活人胚胎干细胞的拷贝数变异

背景：倾斜性与随机X染色体失活的人胚胎干细胞拷贝数变异是否存在差异不清楚。 目的：在全基因组水平分析倾斜性X染色体失活的人胚胎干细胞的拷贝数变异情况,分析其涵盖基因及其对细胞功能产生的影响。 方法：3株倾斜性X染色体失活细胞为研究组,两株随机X染色体失活细胞为对照组。运用美国Affymetrix公司Cytogenetics Whole-Genome 2.7M 芯片对其进行全基因组拷贝数变异分析,数据经ChAS软件、OMIM等工具分析,在3株倾斜性X染色体失活细胞中寻找相同拷贝数变异区域及其涵盖基因。 结果与结论：①研究组中大于50 kb的拷贝数变异数均超过130个,高于对照组的平均36个,两组中拷贝数变异改变均以重复为主(> 70%)。②研究组中共发现9个共同拷贝数变异区域,分布于1q22、1p34.1、6q16.3、7q31.32、11q13.1、16q12.2、19p13.12、Xp22.33及Xq26.2,均为3个拷贝的重复,总共涵盖19个基因。对照组中这些区域及基因均为正常2个拷贝。③拷贝数变异涵盖基因多与DNA及核苷酸结合等功能相关,Xq26.2区域的GPC3基因突变与倾斜性X染色体失活可能有关联。结果表明倾斜性X染色体失活细胞相对随机失活细胞具有更多的微小基因组改变,拷贝数变异涵盖的重要基因可能对人胚胎干细胞功能产生不利影响。     

48,XXYY综合征合并糖尿病1例的X染色体来源和失活偏移分析

目的 初步探讨48,XXYY综合征合并糖尿病患者的临床特点,并分析该疾病的X染色体来源和失活偏移.方法收集患者的临床资料,抽提患者及其父母的外周血基因组DNA,应用PCR结合HpaⅡ限制性内切酶消化法分析X染色体来源和失活偏移.结果 患者临床表现及实验室检查完全符合48,XXYY综合征,使用二甲双胍和睾酮治疗后患者血糖控制平稳.患者X染色体分别来源于父亲和母亲,两条X染色体均为部分失活,偏移度为0.52.结论 48,XXYY综合征合并糖尿病的发病机制可能与睾酮水平低下、胰岛素抵抗有关.48,XXYY综合征多余X染色体来源于父亲,X染色体不一定存在失活偏移.     

X染色体失活致女性X连锁慢性肉芽肿病

目的通过对1例罕见婴幼儿女性X连锁慢性肉肿病(X-CGD)患儿临床及产前产后CYBB基因特征的分析,丰富对该病的认识,并对该病的产前诊断予以警示。方法流式细胞术检测患儿及其父母中性粒细胞呼吸爆发功能及gp91phox蛋白表达情况;PCR直接测序法分析CYBB基因;患儿及父母DNA经酶切后,采用荧光标记PCR扩增,产物用毛细管电泳法检测计算X染色体失活程度。结果患儿,女,2个孪生哥哥均为X-CGD患者,母亲为突变基因携带者。曾行胎儿羊水细胞DNA分析,显示为CYBB exon9 c.1123delG杂合突变,是女性携带者。2月龄时,以肛周脓肿为首发症状,外周血中性粒细胞呼吸爆发功能明显异常,SI=0.65,NBT=0%;gp91phox蛋白无表达。患儿外周血细胞cDNA测序结果显示CYBB exon9 c.1123delG纯合缺失突变。X染色体失活检测,患儿失活率99.5%,其母亲失活率76.1%。结论由于女性携带者有出现正常X染色体失活的可能性,所以产前诊断时,要对胎儿的DNA及cDNA均进行分析,且应对女性CYBB基因杂合突变胎儿行脐带血中性粒细胞呼吸爆发功能检查明确是否为女性患者。     

36例X染色体异常的遗传学分析

目的通过对36例女性性发育异常患者的核型分析,进一步探讨X染色体异常的遗传学效应。方法采用外周血淋巴细胞培养制片、染色体G显带技术进行核型分析。结果36例性发育异常患者中X染色体数目异常26例,结构异常10例。结论女性X染色体异常可导致性腺发育不全,身材矮小,原发闭经,月经紊乱等,两条完整的X染色体对女性性腺及体征的发育是十分重要的。     

子宫平滑肌瘤不同结节X染色体失活类型的研究

目的 探讨多发性子宫平滑肌瘤不同瘤结节之间的关系。方法 提取112例子宫平滑肌瘤和1例子宫平滑肌肉瘤新鲜组织DNA,用甲基化敏感的HhaⅠ或HhaⅡ消化,聚合酶链反应(PCR)扩增雄激素受体(AR)以及磷酸甘油酸酯激酶(PGK)基因。AR基因产物经变性聚丙烯酰胺凝胶电泳、银染显示其长度多态性;PGK基因产物经BstⅪ消化后,琼脂糖电泳显示结果。结果112例子宫平滑肌瘤和1例子宫平滑肌肉瘤标本,AR和PGK位点的多态性发生率分别为89％和30％。对适合于检测的77例共321个瘤结节进行了检测,所有瘤结节均表现为X染色体失活嵌合性丢失,是单克隆性的;对57例多发性肌瘤共295个瘤结节的观察表明,30例标本中所有瘤结节以及7例中大部分瘤结节带有相同的失活X染色体,20例标本中不同瘤结节失活X染色体完全不同;这种差别与核分裂指数以及核怪异和肿瘤退变的出现无关;上述两个位点的数据在所有检测过的标本(10例)均一致;1例多发性病例中不同瘤结节带有完全相同的AR位点杂合性丢失和缺失突变。结论 此研究证实了我们以前的假设,即多结节的子宫平滑肌瘤有多中心型、同源型以及二者的混合型三种,后两者的生物学行为值得进一步探讨。     

脆性X综合征的细胞遗传学研究

本研究从１０个Ｘ－连锁智力低下家系中，经细胞遗传学检查，检测出５个Ｆｒａ（Ｘ）综合征家系，共１５名患者和携带者检查发现：１、不同成份培养液对脆性Ｘ表达有影响。２、活性Ｘ染色体Ｘｑ２７迟复制与Ｆｒａ（Ｘ）综合征患者智力密切相关。３、Ｆｒａ（Ｘ）染色体的活性与女性携带者的智力有一定的关系     

人类X染色体失活与基因的剂量补偿效应

人类通过女性的一条X染色体随机失活的方式对X连锁的基因进行表达的调控,以实现基因的剂量补偿效应,目前对X失活机制的研究表明,X染色体上的失活中心通过表达的非编码RNA对所在染色体进行顺式调控,但结构异常的X染色体的失活并不是随机的,有关X染色体失活机理的研究有待深入。     

脆陛X综合征的细胞遗传学研究

本研究从10个X连锁智力低下家系中，经细胞遗传学检查．检测出5个Fra(X)综合征家系，共15名患者和携带者检查发现：1、不同成份培养液对脆性X表达有影响。2、活性X染色体Xq27迟复制与Fra(X)综合征患者智力密切相关。3、Fra(X)染色体的活性与女性携带者的智力有一定的关系。     

脆性X综合征诊断及临床特征研究

本文对疑脆性X综合征者,将细胞培养于低叶酸培养基中,加入5-氟脱氧尿苷（FudR）和咖啡因双诱导方法,常规制片,G显带分析,结果检出脆性X综合征147例,经过家系调查发现78个家系,其中7个大家系,家系中27例患者fra（X）平均检出率30.89%,最高达42.0%。17例携带者fra（X）平均检出率4.0%。本文还对其临床特征如从家系调查中统计,该征患者27例中有9例癫痫发作,发生率为33.33%。发作多在晚上睡眠期间歇性发作,以强直性阵挛多见,其次为复杂的部分性发作,发作不规律,多在少年。并对行为障碍进行了研究分析。     

Familial Simpson-Golabi-Behmel syndrome: studies of X-chromosome inactivation and clinical phenotypes in two female individuals with GPC3 mutations

Simpson-Golabi-Behmel syndrome (SGBS) is an overgrowth/multiple congenital anomalies syndrome with an X-linked inheritance. Most cases of SGBS are attributed to mutations in the glypican 3-gene (GPC3), which is highly expressed in the mesodermal embryonic tissues and involves in a local growth regulation. Typical clinical features include pre/postnatal overgrowth, developmental delay, macrocephaly, characteristic facies with prominent eyes and macroglossia, diaphragmatic hernia, congenital heart defects, kidney anomalies, and skeletal anomalies. Obligate carrier females with GPC3 mutations are usually asymptomatic or with mild symptoms. It is thought that skewed X-inactivation is the underlining mechanism for the female patients to present with findings of SGBS. We identified three siblings with typical SGBS (two male and one female cases) and their mother with very mild symptoms in a family carrying c.256C>T (p.Arg86X) mutation in GPC3. X-inactivation studies on the androgen-receptor gene (AR) and the Fragile XE (FRAXE) gene were performed with blood, buccal swabs, and fibroblasts in the carrier females. The studies with blood showed moderately skewed X-inactivation with paternal X-chromosome being preferentially inactivated (71-80% inactivated) in the female patient with SGBS and no skewing was shown in the mother with very mild symptoms. The X-inactivation studies in the mother showed inactivation of the X-chromosome with the mutation by 57%. This suggests that loss of the functional GPC3 protein by 43% is closed to the threshold to develop the SGBS phenotype. Studies with buccal swabs and fibroblasts failed to show different X-inactivation patterns between the two female individuals.     

X chromosome inactivation patterns in patients with idiopathic premature ovarian failure

BACKGROUND: X chromosome aberrations have been reported as the cause of extremely skewed X chromosome inactivation (XCI). The purpose of this study was to investigate whether skewed XCI is associated with idiopathic premature ovarian failure (POF). METHODS: The XCI status was evaluated in Korean women by the methylation assay of androgen receptor locus in 126 idiopathic POF patients (35.3 +/- 13.9 years old, mean +/- SD) and 126 age-matched controls (35.2 +/- 13.9 years). The incidence of skewed XCI in POF group was compared with that of control. The correlation between age and skewed XCI was also evaluated within both groups. RESULTS: The incidence of extremely skewed XCI (>or=90%) was 3.9 versus 2.7% (P = 0.710) in POF and control group, respectively. No significant differences were found in the incidence of skewed XCI on all three levels (>or=90, >or=80 and >or=70%) compared between these two groups. The calculation of correlation coefficients showed that, in both POF and control group, there were no significant correlations between age and XCI ratio. Neither was there increasing tendency of skewed XCI according to the increase of age in both groups. Furthermore, there were no significant differences when the XCI ratios were analysed according to the age of onset of ovarian failure. CONCLUSIONS: The incidence of skewed XCI in Korean POF population was not significantly different from control, implying that skewed XCI may not be associated with idiopathic POF. There were also no significant correlations between age and skewed X-inactivation patterns in both groups.     

X-inactivation patterns in monozygotic and dizygotic female twins

We have tested the hypothesis that contrasting X-inactivation patterns could be a trigger for monozygotic twinning in females. X-inactivation patterns were studied in umbilical cord tissue in 43 monozygotic twin pairs and 24 dizygotic twin pairs. Very skewed or non-random X-inactivation patterns were observed in both twins in six of the monozygotic twin pairs and in one of the dizygotic twin pairs. Contrasting X-inactivation patterns occurred in only one of the six monozygotic twin pairs. This does not support the original hypothesis. There is a trend to extreme skewing of X-inactivation pattern occurring more frequently in monozygotic twins. © 1996 Wiley-Liss, Inc.     

X-inactivation pattern in the liver of a manifesting female with ornithine transcarbamylase (OTC) deficiency

Ornithine transcarbamylase (OTC) deficiency is the most common urea cycle disorder. It is X-linked and hemizygous new-born males usually suffer fatal hyperammonemia. In contrast, carrier females manifest variable phenotypes, ranging from asymptomatic carriers to those with severe hyperammonemia. In order to understand the correlation between X-inactivation status and the clinical phenotype of carrier females with this disorder, we analyzed the X-inactivation pattern of peripheral blood leukocytes in a family consisting of a clinically normal mother and two daughters with severe manifestation. In addition, we obtained tissue samples from various parts of the liver of one of these daughters and analyzed X-inactivation patterns and the residual OTC activities. The X-inactivation of peripheral blood leukocytes was nearly random in these carrier females and showed no correlation with the disease phenotype. However, the X-inactivation of the liver was much more skewed and correlated well with the OTC activity of all samples. Interestingly, the degree of X-inactivation varied considerably, even within the same liver.     

脑干听觉反应（ABR）在青少年精神分裂症和孤独症中的应用

目的：探讨青少年精神分裂症（AS）和孤独症儿童（AC）在脑干听觉反应（ABR）检测中的特点。方法：应用美国Nicolet Bravo脑电生理仪及Click短声刺激,测查32例AS和30例孤独症（AC）和40名健康儿童（NC）的ABR。结果：AS组、AC组及NC组在绝对潜伏期波Ⅲ（Oz脑区）,绝对波幅波Ⅲ（Oz脑区）,波V（Oz脑区）上有差异极显著性（P〈0．01）。与NC组和AS组相比,绝对潜伏期波Ⅲ（Oz脑区）上,AC组延迟于NC组和AS组（P〈0．01）。波幅分析所见,绝对波幅Ⅲ（Oz脑区）AC组低于NC组和AS组（P〈0．01）;绝对波幅波V（Oz脑区）AC组也低于NC组和AS组。AS组与NC组比较,差异未达显著性（P〉0．05）。结论：ABR对临床辅助诊断AC和AS有初步参考价值。     

两种冷冻方法对人大块卵巢组织卵泡活性的影响

目的 探讨两种冷冻方法冻融人类大块卵巢组织的冷冻效果及对卵泡活性的影响。方法 收集15例人卵巢组织,每例修剪成3块卵巢组织
（约15 mm×15 mm×2mm）,分别随机分配到新鲜对照组（A组）、玻璃化冷冻组（B组）、两步法冷冻组（C组）,组织学分析3组卵泡形态学变
化,并进行卵巢组织体外培养后测定培养液上清中雌激素、孕激素浓度,免疫组织化学染色测定培养后的卵巢组织细胞核增殖相关抗原Ki67 及
B细胞淋巴瘤/白血病-2基因（Bcl-2）表达水平,评估卵泡增殖及凋亡活性。结果 A组正常形态卵泡比率（91.9%）显著高于B组（71.3%）和C组
（82.9%）,差异有统计学意义(P<0.05),C组高于B组,差异有统计学意义(P<0.05)。C组的始基卵泡和初级卵泡的正常形态率分别为86.8%、
54.4%,均分别高于B组73.8%、44.4%,差异有统计学意义(P<0.05)。同一时期3组激素测定结果差异不显著(P>0.05)。C组Ki67的阳性率为73%,
分别显著高于A组50%和B组55%(P<0.05),A组低于B组(P<0.05)。Bcl-2阳性率,A组为57%和C组61%相比无差异(P>0.05),但B组42%阳性率分别低
于A组和C组(P<0.05)。结论 人体大块卵巢组织冻融后仍具有活性,并且两步法冻存效果优于玻璃化冷冻法。     

胱抑素C在2型糖尿病肾病早期诊断中的意义

目的 分析2型糖尿病肾病患者血清胱抑素C（cystatin C,CysC）的水平,为临床早期诊断提供依据.方法 对本院133例2型糖尿病患者进行回顾性分析,根据24h尿微量白蛋白排泄率（UAER）,将其分成三组：一组为单纯糖尿病组（UAER＜30mg/24h）（B组）,共58例,平均年龄56.6岁,其中男性28例,女性30例;二组为早期糖尿病肾病组（30 rmg/24h＜UAER＜300mg/24h）（C组）,共41例,平均年龄58.5岁,其中男性20例,女性21例;三组为糖尿病肾病组（UAER＞ 300mg/24h）（D组）,共34例,平均年龄63.5岁,其中男性17例,女性17例.同时设立健康对照组（A组）50例,平均年龄61.8岁,其中男性24例,女性26例.四组分别测定CysC、血清肌酐（scr）、血清尿素氮（BUN）及UAER,并对所得数据进行分析.结果 D组CysC、Scr、BUN及UAER均高于A组（P＜0.01）,C组CysC、UAER均高于A、B组（P＜0.05）,B组CysC、UAER均高于A组（P＜0.05）,C组Scr、BUN均高于A、B组（P＜0.05）,而Scr、BUN在A、B两组间差异无统计学意义（P＞0.05）;CysC与UAER相关性良好（r=0.656,P＜0.01）,与Scr、BUN无相关性.结论相对于Scr和BUN,CysC在糖尿病肾病时升高较早而且明显,与UAER联合检测可以作为糖尿病肾病早期的预测指标.     

13C-尿素呼气试验检测胃幽门螺杆菌感染2275例报告

目的 了解全年龄段有消化道症状患者的幽门螺杆菌（Hp）感染情况.方法 选取本院门诊及住院有慢性上腹疼痛、反复上消化道出血等消化道症状的患者共2275例,年龄2 ～88岁,男1058例,女1217例.采用13C-尿素呼气试验的检测方法,分析幽门螺杆菌感染的检测结果.结果 2275例患者中,13C-尿素呼气试验阳性者928例,占40.79％.男性患者,阳性414例,占39.13％;女性患者,阳性514例,占42.23％,女性高于男性（P＜0.01）.各全年龄段中,以31 ～45岁年龄组幽门螺杆菌感染率为最高,阳性333例,占48.40％.成人各年龄段与15岁以下年龄组相比,HP感染率差异有统计学意义（P＜0.01）.结论 对31 ～45岁年龄段的人群应给予关注,同时应通过健康教育提高人们的相关知识水平,有针对性地开展Hp筛查,早诊断、早治疗,从而有效预防和控制胃部疾病的发生.     

HBeAg阳性与HBeAg阴性慢性HBV携带者肝组织病理结果分析

目的探讨HBeAg阳性与HBeAg阴性慢性HBV携带者肝组织病理学特征及临床意义。方法采用回顾性分析方法,收集2002年1月-2009年12月住院的198例HBeAg阳性与HBeAg阴性慢性HBV携带者,所有患者均进行肝穿刺组织活检,分析病理特征。结果 198例慢性HBV携带者HBeAg阳性134例（占67.68%）,HBeAg阴性64例（占32.32%）,除21例（占10.61%）无肝脏病理改变外,其余肝脏组织学显示不同程度炎症（G）及纤维化（S）改变者占89.39%（177/198）,其中G1占65.66%（130/198）,G2占19.19%（38/198）,G3占4.55%（9/198）,≥G2共占23.74%（47/198）;S1占39.90%（79/198）,S2占36.87%（73/198）,S3占5.05%（10/198）,S4占0.51%（1/198）,≥S2共占42.42%（84/198）。男性组与女性组G、S比较差异均无统计学意义（P均〉0.05）;年龄≥30岁组G及S重于〈30岁组（P〈0.05）。病程〈10年组与≥10年组G比较差异无统计学意义（P〉0.05）,病程≥10年组S重于〈10年组（P〈0.05）。按HBeAg分阳性组与阴性组,HBeAg阳性组以G1（占70.89%）、S1（占47.01%）为多,而HBeAg阴性组以≥G2（占34.38%）、≥S2（占56.25%）为多,差异有统计学意义（P〈0.05）。HBeAg阳性组肝组织G各级之间及S各期之间血清HBVDNA水平比较差异均无统计学意义（分别为χ^=23.117,df=3,P=0.366;χ^2=5.579,df=3,P=0.134）;HBeAg阴性组肝组织G各级之间及S各期之间血清HBVDNA水平比较差异亦无统计学意义（分别为χ^=20.921,df=3,P=0.823;χ^=23.408,df=3,P=0.492）。结论无论HBeAg阳性或HBeAg阴性慢性HBV携带者绝大部分有一定的肝组织学改变,应引起足够重视;HBeAg阴性慢性HBV携带者的肝组织损害程度要重于HBeAg阳性者。肝组织学炎症、纤维化程度改变与乙肝病毒复制水平、性别无关。年龄≥30岁组炎症及纤维化程度重于〈30岁组,病程≥10年组纤维化程度重于〈10年组。年龄在30岁以上,病程超过10年的慢性HBV携带者应密切随访,及时进行肝活检,明确病情,并给予恰当的治疗。     

Clinical features in 27 patients with Angelman syndrome resulting from DNA deletion.

We report the clinical features in 27 Australasian patients with Angelman syndrome (AS), all with a DNA deletion involving chromosome 15(q11-13), spanning markers from D15S9 to D15S12, about 3 center dot 5 Mb of DNA. There were nine males and 18 females. All cases were sporadic. The mean age at last review (end of 1994) was 11 center dot 2 years (range 3 to 34 years). All patients were ataxic, severely retarded, and lacking recognisable speech. In all patients, head circumference (HC) at birth was normal but skewed in distribution, with 62 center dot 5% at the 10th centile. At last review HC was around the 50th centile in three patients (12 center dot 5%) while 15 had poor postnatal head growth. Short stature was not invariable, 5/26 (19%) were on or above the 50th centile. Hypotonia at birth was recorded in 15/24 (63%) and neonatal feeding difficulties were recorded in 20/26 (77%). Epilepsy was present in 26/27 (96%) with onset by the third year of life in 20 patients (83%). Improvement in epilepsy was reported in 11/16 patients (69%) with age. An abnormal EEG was reported in 25/25 patients. Hypopigmentation was present in 19/26 (73%). One patient had oculocutaneous albinism. Five patients could not walk independently. Of the remaining 22 who could walk, age of onset of walking ranged from 2 to 8 years. Disrupted sleep patterns were present in 18/21 patients (86%), with improvement in 9/12 patients (75%) over 10 years of age. The clinical features in this group of deletional AS patients were similar to previous reports, but these have not separated patients into subgroups based on DNA studies. In our group of deletional cases, 100% showed severe mental retardation, ataxic movements, absent language, abnormal EEG, happy disposition (noted in infancy in 95%), normal birth weight and head circumference at birth, and a large, wide mouth. These features occurred with a higher frequency than in AS patients as a whole. Our study also provided information on the evolution of the phenotype. The data can act as a benchmark for comparisons of AS resulting from other genetic mechanisms.