中低度近视眼遗传流行病学研究

目的 探讨中低度近视眼与遗传的关系。方法 对51对双生子进行扩瞳视网膜检影验光，视力不良者进行眼科常规检查及眼底检查，统计中低度近视眼的发病情况，并分别计算单卵双生和双卵双生发病一致率及遗传率。结果 单卵双生和双卵双生发病一致率分别为77．27％，31．03％；中低度近视眼的遗传率为67．04％。结论 遗传因素对中低度近视眼的形成起重要作用，并且其遗传因素大于环境因素，其遗传方式为多基因遗传。     

人体腺苷脱氨酶活性的遗传性探讨

作者采用卵性鉴定准确性在98％以上的双生子法,对22对单卵双生子及16对双卵双生子进行腺苷脱氨酶(ADA)活性的遗传性研究。结果发现,单卵双生子对的ADA活性相关系数为0.73,双卵双生子对的ADA活性相关系数仅为0.47。说明遗传因素对血中ADA活性的大小起着一定作用,但不能忽视环境因素的影响。用四种方法计算,其遗传度为49～80％。     

双生子视网膜母细胞瘤遗传学和临床表现

报告一对经生育史,红细胞血型(ABO、MN、Rh、P),血清型(Hp,Gc),酯酶D(EsD)表型及HLA(A、B、Cw)多种遗传标记检测而确诊为同卵双生子的视网膜母细胞瘤病例,同时于45天出现“猫眼”症状,孪生弟右眼、孪生兄双眼眼球摘除后,病理检查证实为视网膜母细胞瘤(Rb),分化型。文章结合本世纪文献报道作过卵性诊断的Rb双生子共33对,计算出同卵双生患病一致率和Rb的遗传指数(76.56％);并就双生子卵别鉴定项目的可靠程度,“镜像”现象以及如何用Knudson的“二次突变”假说来解释同卵双生子发病一致性的问题,作了简要的讨论。     

双胎方式对双胎儿童智能发育的影响

目的 :研究双胎方式对双胎儿童智能发育的影响。方法 :将 114例双胎儿童按照双胎方式分为单卵双生和双卵双生组 ,同时用绘人试验对其智能进行了测验 ,比较两组儿童智商 (IQ值 )的差异。结果 :单卵双生组IQ值明显高于双卵双生组 (P <0 0 5 ) ,且中下智商人数的比例明显低于后组 ,而中上智商的比例显著高于后组 (P <0 0 1)。结论 :双胎方式可以对双胎儿童的智能发育造成影响。     

微小RNA在精神分裂症中的研究进展

精神分裂症病因不明.大量的研究显示遗传因素在精神分裂症发病中起着重要的作用[1],但同卵双生的发病一致率仅为41％ ～ 65％[2]的研究结论也提示该病与环境因素同样密切.微小RNA( microRNAs,miRNAs)参与调节人体三分之一蛋白质编码基因表达的调控,推测其可能是大脑紊乱性疾病的分子基础[3],其在精神分裂症发病中的作用值得研究.本文就miRNA 在精神分裂症中的相关研究进行综述.     

系统性红斑狼疮基因表达谱的芯片分析

系统性红斑狼疮(SLE)是一种慢性自身免疫性疾病，其发病机制复杂，主要包括遗传因素和环境因素。SLE的遗传性很强，同胞的患病率／一般人群患病率(λs)大于20，同卵双生子发病一致率为24％～65％，而异卵双生子发病一致率仅2％～9％。     

母女同患系统性红斑狼疮临床分析

系统性红斑狼疮(systemic lupus erythematous,SLE )是一种自身免疫系统疾病,以自身反应细胞的活化和大量自身抗体的产生为其主要免疫病理学特点[1].在发病机制上,遗传起到了非常重要的作用,具有高度家族危险性,临床报道多为同胞、同卵双生及异卵双生,母女同时患病较少,现将我们收治的母女同患SLE病例报告如下.     

抑郁症的病因探讨

1生物因素遗传因素：调查表明，抑郁症患者的家属中患有同类疾病者高于居民的平均水平，患病的可能性大约是普通人的匕借。血缘关系越近，患病机率越高。孪生儿检查结果显示，单卵孪生儿患病一致性较高，而双卵孪生儿与其兄弟姐妹之间无显著差别。单卵双生儿的患病一致性比其他人高2～4倍。单卵孪生儿的患病一致性平均为70％，双卵孪生儿平均为20％，孪生儿分开成长与共同成长的患病一致性并没有很大差别。较多学者认为，本病并非由个别基因所决定，而是由具有连续变异性的多基因共同作用的结果。遗传学研究提示，该病的形成受遗传因素的影…     

基因在类风湿关节炎中的相对重要性：丹麦全国双胞胎人群的历史性队列研究

目的：了解环境和基因在类风湿关节炎（Rheumatoid Arhritis,RA)发病中的相对重要性。设计，将丹麦双胞胎登记和出院登记记录相结合进行历史性队列研究，同时用丹麦全国性死亡登记来评介本研究的完整性。背景：以两组人群为基础的全国双胞胎队列研究。参加：本研究共向37338例双胞胎发送了有关风湿性疾病的问卷，对本人自报患有RA的患进行了临床检查并从医院的病记录中到证实。主要的测定结果：同卵双生和异卵双生与先证RA的共患率。结果：问卷回应率为84．7％，经证实有13例同卵双生和36例异卵双生患有RA，在同卵双生对中无共患RA，在异卵双生对中共患RA的有2对，以捕获－再捕获方法确认的可能性为78．3％，与先证共患率在同卵双生中为0（95％可信区间为0－24．7），在异卵双生为8．8（1．9－23．7）。结论：基因在RA发病中仅起次要作用。     

浅析我国妇女生育双胞胎状况及其原因

１９８９年，我国妇女双胞胎生育率是０．７９％，其中一卵双生占２６．８３％，二卵双生占７３．１７％。双胞胎出生率最高的是山东省，为１．４３％；最低的是西藏，只有０．４２％。一卵双生率最高的是上海，达５８．５４％；最低的是山东，为０。上海、北京同性别双生儿中，主要是一卵双生，而山西同性别双生儿中主要是二卵双生。我国妇女在１５～３９岁年龄段中，３３岁妇女双生率最大（１．３３％），１５岁双生率最小（０．３％）。一卵双生和二卵双生既与遗传有关，也与环境有关，因此，一卵双生和二卵双生可能属于数量性状。     

Idiopathic hypertrophic pyloric stenosis in identical twins

Idiopathic hypertrophic pyloric stenosis (IHPS) was thought to be a congenital disease traditionally, even though several published reports assumed IHPS was an acquired disease. The pathogenesis and inheritance patterns of IHPS are not fully understood. Except for the familial recurrence of IHPS, concordance of IHPS in monozygotic or dizygotic twins was also noted, but occurrence in female twins is rare. From July 1992 through June 2000, 130 patients were diagnosed with IHPS in our hospital including one pair of female twins. We present the finding in the twins and review the associated articles about the pathogenesis and inheritance patterns of IHPS.     

Use of the lambda sign in fetal reduction of dizygotic triplets after intracytoplasmic sperm injection

With the increased use of artificial reproductive technologies, there are ever greater numbers of multifetal pregnancies. The increased incidences of monozygotic twins and triplet gestations can be attributed to several factors. It is important to differentiate the chorionicity in the management of multifetal pregnancies because monochorionic gestations lead to an increased risk of prematurity, twin-to-twin transfusion, morbidity, and mortality. In a dizygotic triplet pregnancy, increased risks of obstetric complications result from the monozygotic twins, such as twin-to-twin transfusion, as well as from the presence of triplets. Fetal reduction can lower these risks. During the first trimester, a "lambda sign" on ultrasound can differentiate between monozygotic twins and a separate fetus. In this paper, we present selective fetal reduction of 1 of the monozygotic twins in order to reduce the risks resulting from either monozygotic twins or from triplets. By sacrificing 1 monozygotic twin, we believe the quality of life of the remaining babies in this case were improved.     

THE STUDY OF DENTAL CARIES AMONG 280 TWIN PAIRS

The twin study was intent a to estimate the relative influence of hereditary factors and environmental factors in causing caries. The subjects selected from the city Beijing, China, are 280 same-sexed twin pairs. 186 pairs are monozygotic (MZ) twins; the other 94 pairs are dizygotic (DZ) twins. The total sample involved in the present study was significantly great in size and different statistical methods of analysis were adopted. The conclusion reached is such that non-genetic factors rather than genetic factors have more influence in causing caries.     

遗传和环境对于男性开始吸烟影响的双生子研究

目的：分析遗传和环境因素分别对于男性吸烟行为和开始吸烟年龄的影响。方法：回顾性调查1 006对18岁及以上成年双生子的吸烟状况及开始吸烟年龄,在分析同卵和异卵双生子同吸烟率的基础上分别计算吸烟行为和开始吸烟年龄的遗传度。结果：与西方文化不同,该双生子人群中男性吸烟比例达66.8%,相比之下女性仅有0.2%。同卵双生子中, 88.7%(566/638对)的双生子对中两个成员都是吸烟者或者具有吸烟经历或均不吸烟,而异卵双生子此比例仅为63.6%(234/368对)。该双生子样本吸烟行为的遗传度为69.0%±4.1%。双生子平均开始吸烟年龄（20.4±5.3）岁,同卵双生子开始吸烟年龄相关系数0.393,而异卵双生子达0.860。结论：中等程度的遗传度显示遗传因素对于男性双生子选择是否吸烟具有一定的影响,但是什么时候开始吸烟,更多取决于个人环境的影响。     

芜湖市198对双生儿的调查分析

通过对芜湖市中、小学和幼儿园的58 887名学生的普查,发现198对双生子,双生子发生率为3.4‰,其中同卵双生占60.77％,异卵双生占39.23％。本文就双生子的胎次和父母育龄的分布;双生子的智力、体征;双生与遗传等方面进行了研究。     

成年双生子血压水平与DNA甲基化相关性研究

目的：在成年双生子人群中探索与血压指标（收缩压、舒张压、平均动脉压、脉压）存在相关性的DNA甲基化位点。方法：研究人群来自中国双生子登记系统,共476名双生子,问卷调查包括一般人口学特征、生活方式及疾病状况等信息,体格检查包括血压、身高、体重等信息,使用Infinium HumanMethylation450 BeadChip芯片对外周全血进行全基因组DNA甲基化检测。在调整潜在混杂因素的基础上,通过构建混合效应模型在全基因组范围寻找与血压指标存在相关性的DNA甲基化位点,显著性水平为错误发现阳性位点率<0.05。结果：经过数据质量控制最终纳入465名双生子（122对同卵双生子,104对异卵双生子,13对双生子的其中之一）,年龄(44.8±13.2)岁,男性多于女性,同卵略多于异卵,目前吸烟和目前规律饮酒者所占比例均大于30%。所有双生子个体均行全基因组DNA甲基化与血压指标相关分析,经多重校正后未发现显著的甲基化位点,但位于10号染色体的cg07761116在3个血压指标（收缩压、舒张压、平均动脉压）相关分析中的P值相对较小, 提示其可能是一个与血压相关的位点。还有7个位点在两个血压指标相关分析中的P值较小,所在基因与神经发育、蛋白质稳态、炎症反应等功能相关。结论：没有明确证据支持与血压水平存在相关性的甲基化位点,可能由于样本量不足等原因,可以为后续开展类似的双生子研究提供参考,后续研究可以关注10号染色体上的cg07761116及其他P值较小的位点。     

The heritability of otitis media: a twin and triplet study

CONTEXT: Anatomical, physiological, and epidemiological data indicate that there may be a significant genetic component to prolonged time with and recurrent episodes of otitis media in children. OBJECTIVE: To determine the genetic component of time with and episodes of middle ear effusion and acute otitis media (AOM) during the first 2 years of life. DESIGN: Prospective twin and triplet cohort study with enrollment from 1982 through 1995. SETTING: Otitis Media Research Center in the ear, nose, and throat clinic of Children's Hospital of Pittsburgh, Pittsburgh, Pa. PATIENTS: A total of 168 healthy same-sex twin and 7 triplet sets were recruited within the first 2 months of life; zygosity results were available for 140 sets; 138 (99%) of these were followed up for 1 year and 126 (90%) for 2 years. MAIN OUTCOME MEASURES: Proportion of time with middle ear effusion, episodes of middle ear effusion, and episodes of AOM by zygosity status. RESULTS: At the 2-year end point, the estimate of heritability of time with middle ear effusion was 0.73 (P<.001). The estimates of discordance for 3 or more episodes of middle ear effusion were 0.04 for monozygotic twins and 0.37 for dizygotic twins (P = .01). The estimate of discordance of an episode of AOM in monozygotic twins was 0.04 compared with 0.49 in dizygotic twins (P = .005). CONCLUSIONS: Our study suggests there is a strong genetic component to the amount of time with middle ear effusion and episodes of middle ear effusion and AOM in children.     

A twin study of human obesity

Height, weight, and body mass index (BMI) were assessed in a sample of 1974 monozygotic and 2097 dizygotic male twin pairs. Concordance rates for different degrees of overweight were twice as high for monozygotic twins as for dizygotic twins. Classic twin methods estimated a high heritability for height, weight, and BMI, both at age 20 years (.80, .78, and .77, respectively) and at a 25-year follow-up (.80, .81, and .84, respectively). Height, weight, and BMI were highly correlated across time, and a path analysis suggested that the major part of that covariation was genetic. These results are similar to those of other twin studies of these measures and suggest that human fatness is under substantial genetic control.     

双生子皮下脂肪厚度的研究

本文对110对7岁～12岁同性别双生儿童皮脂厚度的研究表明,小学儿童体脂肪的变异受遗传因素的影响较大,其遗传度为0.62～0.75;不同部位皮脂厚度受遗传因素的影响程度不同,肩胛下角处遗传度较高(0.65～0.82),而三头肌处则较低(0.32～0.43)。