产前超声诊断及漏诊胎儿肢体畸形分析

目的：探讨胎儿肢体畸形超声特征及诊断价值。方法：采用连续顺序追踪法对66342 例妊娠12-40 周孕妇行胎儿四肢畸形筛查。将产前超声诊断结果与引产或产后结果进行对比分析。结果：发生肢体畸形271 例,发生率为0.41 %（271/66342）,包括四肢短小5 例,桡骨发育不全1 例,缺肢畸形5 例,足内翻17 例,手掌畸形3 例,指趾畸形222 例及骨骼多发畸形18 例。其中产前诊断胎儿肢体畸形49 例;漏诊222 例,包括：足内翻3 例、指趾畸形218 例、多发骨骼畸形1 例。胎儿肢体畸形的出现率和产前检出率分别为：四肢短小1.84 %（5/271）、100 %（5/5）;桡骨发育不全0.36 %（1/271）、100 %（1/1）;缺肢畸形1.84 %（5/271）、100 %（5/5）;足内翻6.27 %（17/271）、82.35 %（14/17）;手掌畸形1.10 %（3/271）、100 %（3/3）;指趾畸形81.91 %（222/217）、1. 8%（4/222）;多发骨骼畸形6.64 %（18/271）、94.44 %（17/18）。结论：超声对胎儿手掌、脚掌部位以上畸形的检出率较高。指趾畸形出现率最高,但检出率最低。     

产前超声诊断胎儿肢体畸形的效果观察

目的探讨产前超声诊断胎儿肢体畸形的效果。方法选择2015年4月~2016年4月在我院行产前检查的孕妇1180例,均采用彩色多普勒超声诊断仪进行产前超声检查,并观察产前超声诊断胎儿肢体畸形的临床应用效果。结果本组1180例孕妇中,检出肢体畸形胎儿38例,检测率为3.22%,其中脚缺失胎儿5例(13.16%),手畸形胎儿8例(21.05%),足内翻畸形胎儿6例(15.79%),股骨歪曲胎儿6例(15.79%),上肢畸形胎儿3例(7.89%),桡骨缺损胎儿8例(21.05%),六指畸形胎儿2例(5.26%)。超声诊断胎儿肢体畸形者均行引产手术,引产结果与超声诊断结果相符。结论产前超声检查在胎儿肢体畸形诊断中具有较高检测价值,能够有效检查出胎儿肢体发育情况,对提高人口质量具有重要意义。     

胎儿中晚孕期产前超声筛查胎儿畸形的临床价值

目的:分析胎儿中晚孕期产前超声筛查胎儿畸形的临床价值。方法:选取我院2011年1月到2013年1月间胎儿早孕期超声检测正常孕妇1240例,于胎儿中孕期(孕21~25周)和晚孕期(孕31~35周)各再进行一次超声检测工作,用Excel表进行统计分析,分类归纳统计胎儿畸形分类及各类畸形超声检出时间。结果:1240例胎儿早期超声检测正常孕妇中,胎儿中孕期检测显示胎儿畸形16例,检出率1.3%;其中中枢神经畸形3例,心脏畸形1例,前腹壁畸形2例,泌尿系统畸形1例,骨骼以及四肢畸形2例,双胎畸形2例,消化系统畸形2例,胎儿肿瘤1例,胎儿水肿1例,指趾异常1例,胎儿晚孕期检测显示有畸形3例,检出率为0.24%,分别为面部畸形1例,指趾异常1例,心脏畸形1例。这19例胎儿均证实为畸形胎儿。胎儿中孕期漏诊3例,漏诊率15.8%(3/19)。结论:超声检查是产前诊断胎儿畸形的重要诊断方法,诊断率高,安全性大,但部分胎儿畸形在中孕期超声仍未能诊断,所以对胎儿晚孕期再次行超声筛查工作,尤其注意对胎儿颜面部、心脏,颅脑,四肢等器官仔细的扫描,可有效提高畸形胎儿检测率,减少相应畸形的漏诊,为产科医生临床确诊和处理提供有效参考,具有极高的临床价值,同时可减少出生缺陷的发生,配合国家人口系统完成出生缺陷一级预防工作。     

短指/趾的分子遗传学研究进展

短指/趾(Brachydactyly, BD)是指(趾)骨和/或掌(跖)骨短小、缺失或融合导致的手/足先天畸形, 是一组以骨发育障碍为特征的肢体畸形疾病。BD可单独出现, 也可作为综合征的一种体征, 还可伴随其他的手/足畸形如并指/趾、多指/趾、短缺畸形和指/趾骨关节融合出现。绝大多数单纯型BD呈常染色体显性遗传, 存在表现度不同和外显不全。大多数单纯型BD和一些综合征型BD的致病基因缺陷已经被鉴定。BMP (Bone morphogenetic protein)通路参与正常指/趾发育, 且已知的BD致病基因直接或间接参与该通路。文章综述了BD分子遗传学研究方面的新进展, 将有助于BD致病机制的研究和基因诊疗的开展。     

骨骼畸形大鼠软骨细胞内胰岛素样生长因子-2的表达研究

目的 探讨胰岛素样生长因子-2(Insulin-like growth factor 2,IGF-2) 在骨骼畸形大鼠肢端软骨细胞内的表达规律.方法 应用光镜和透射电镜观测二(哑)英诱导的骨骼畸形大鼠足部软骨组织病理学改变.应用二(哑)英(1×10-8mol/L)干预体外培养的大鼠软骨细胞,采用RT-PCR及western 印迹杂交检测软骨细胞内的IGF-2 mRNA及蛋白质的表达水平.结果 15 μg/kg剂量的二(哑)英诱导实验组胎鼠出现多种畸形,内翻足、无尾畸形、腭裂等骨骼畸形发生率为33.3%.畸形胎鼠的肢端骨化中心发生带缩小,软骨细胞核内粗面内质网扩张,线粒体嵴紊乱.1×10-8mol/L剂量的二(哑)英使体外培养的大鼠软骨细胞内IGF-2 的mRNA及蛋白质的表达水平分别减少80%和60%(P＜0.05).结论 在二(哑)英诱导的骨骼畸形大鼠软骨细胞内IGF-2呈低表达状态.软骨细胞内IGF-2 的表达可能与骨骼发育密切相关.     

指（趾）骨异常及其相关基因研究进展

指(趾)骨异常是人群中较为常见的一种遗传缺陷,一般为常染色体显性遗传,也有少数以常染色体隐性遗传的方式传递,包括四肢大范围的缺失缺陷,也包括细微的指(趾)数目、长度、解剖形态结构的变化,是由于遗传进化过程中的变异或发育过程中的不良因素(如异常子宫内环境)所致.指(趾)骨异常可以分为多指(趾)并指(趾)症(Synpolydactyly,SPD)、手足裂畸形(split-hand/split-foot malformation,SHFM)和短指(趾)(Brachydactyly,BD).本文综述了指(趾)骨异常的分类及其遗传特点,总结了指(趾)骨异常畸形相关基因的研究进展.     

染色体10q24.31片段重复导致先天性缺指/缺趾畸形的一个家系致病机理分析

先天性缺指/缺趾畸形表现为手足指/趾骨发育不全等症状,会严重影响患者生活中的精细操作及心理健康。本研究对一个患有先天性缺指/缺趾畸形家系进行了基因变异检测,分析总结了该疾病分型与基因变异之间的关联关系,并探讨了对此类疾病患者开展遗传咨询及基因诊断的策略。首先,采用临床体检及四肢X线检查的方式,对患者表型进行分析。然后,应用D10S1709、D10S192、D10S597、D10S1693和D10S587等5个位点对外周血DNA进行了单倍型分析,并利用Array-CGH检测基因重复片段。最后,通过基于家系调查和基因分析探讨先天性手足裂畸形的致病原因。研究结果显示,先证者为典型的先天性手足裂畸形,表现为双侧食、中指缺失,拇指短,左手无名指畸形与缺失中指的皮肤相连成蹼状;双足正中裂开至足中部,第2和3趾缺失,第4和5趾融合。家系中其他患者表型变异较大。其外周血基因单倍型分析表现为染色体10q24.31-10q24.32区域有一个至少610 kb的重复,Array-CGH分析结果为10q24.31(102 832 650～103 511 083)×3。对先证者及其弟弟和父母进行单倍型分析,确认该家系的致病基因为10q24.31-10q24.32基因重复,单倍型165-251-289-219-102为该病的等位基因。研究结果提示,该家系缺指/缺趾畸形乃由于染色体10q24.31 (102 832650～103511083)×3引起,其单倍型165-251-289-219-102可作为检测10q24.31-10q24.32等位基因的疾病标志物。     

短指(趾)症及指(趾)骨发育的分子调控机制

短指(趾)症(brachydactyly, BD)是一类指(趾)骨或掌(跖)骨的异常缩短或缺失而造成的手/足畸形病变。从临床表型上短指(趾)症可以分为单纯型短指(趾)症以及包含短指(趾)症状的综合征,其中单纯型短指(趾)症又分为5种类型:BDA、BDB、BDC、BDD和BDE,而每一类型又分为不同的亚型。作为一类重要的分子疾病家族,随着对每种短指(趾)症的深入研究,大多数单纯型短指(趾)症和部分综合征的致病基因及其分子机制逐渐被发现。虽然短指(趾)症在表型上高度多样化,但在分子水平上这些致病基因主要影响Hedgehog、NOTCH、WNT和BMP等信号传导通路。这些信号传导通路组成了一个复杂的信号调控网络,在指(趾)骨及关节的不同发育阶段发挥着不同的作用,其中BMP信号传导通路扮演着至为关键的角色。本文在目前对短指(趾)症的分类基础上,详细综述了短指(趾)症相关致病基因及所影响的信号通路等方面的最新进展,旨在探讨指(趾)骨形成的分子机制,以期为短指(趾)症的临床诊断以及人类骨骼发育的分子调控机制研究提供参考。     

胎儿唇裂与唇腭裂产前超声诊断分析

目的:探讨超声诊断胎儿唇裂与唇腭裂的图像特征,以提高胎儿唇裂及唇腭裂的确诊率。方法:选取我院2013年1月~2013年12月的2381例产前超声筛查检查出的17例唇腭裂胎儿,经二维三维超声检查后与出生后颜面部检查结果比较。结果:17例唇腭裂胎儿共检查出16例,漏检1例,检出准确率94.12%,其中1例完全唇裂伴完全腭裂仅检查出唇裂,误检率5.88%。其中未合并其他畸形胎儿16例(94.12%,16/17),完全唇裂伴完全腭裂13例(76.47%,13/17),单纯唇裂2例(11.76%,2/17),单纯腭裂1例(5.88%,1/17);唇腭裂合并其他畸形胎儿1例。结论:产前进行超声检查在胎儿唇裂和唇腭裂诊断中具有显著作用,发现唇裂或唇腭裂后可经多次反复检查确诊,对于部分胎儿可能存在患有唇裂或唇腭裂而漏检情况。     

胎儿肢体畸形的超声诊断与染色体异常的相关性分析

目的：总结肢体畸形胎儿的超声诊断与染色体核型诊断结果,分析胎儿肢体畸形时超声诊断与染色体异常的相关性。方法：以孕18—32周的健康自愿者作为对照组（A组）,以同期超声诊断异常者作为观察组（B组）,两组均行超声及染色体检查。对比其染色体核型的检出情况;并以胎儿的超声诊断结果为自变量,以各染色体核型为因变量进行logistic回归分析。结果：A组染色体异常的检出率为2．1,与之相比,B组染色体异常检出率有明显升高,且染色体核型异常以47,XY,＋18、47,XX＋21和47,XXX为主,差异有统计学意义,P〈0．05;logistic分析结果显示,染色体核型异常与胎儿肢体比例失调、四肢短小、肢体非功能位的OR值分别为6．332、7．404、5．98l,P〈0．05,差异显著。结论：胎儿肢体畸形患者染色体异常的诊出率较健康人群明显增高,染色体核型异常与超声诊断为胎儿肢体比例失调、四肢短小、肢体非功能位的比例呈正相关。     

Cell death and abnormalities in limb morphogenesis ofPleurodeles waltlii Michah. (urodela,amphibia) after nitrogen mustard treatment

Summary The effects of nitrogen mustard (methylbis-chlorethylamine) on limb organogenesis were studied inPleurodeles waltlii at different stages of fore and hind limb development.The effects of four different doses of nitrogen mustard (1.25; 2.5; 5 and 10 g/ml) on the limb bud mesoderm and epidermis were studied histologically. This analysis was carried out on cylindrical unchondrified hind limb buds treated at stage 45.The effects of these doses on all stages of fore and hind limb development were investigated. This included the effect on the establishment of the proximo-distal sequence (segment chondrification) and the antero-posterior sequence (pre-postaxial zeugopod, basipod chondrification and progressive pre-postaxial organization of fingers and toes.Correlations were established between the mesodermal necrosis observed in hind limb buds treated at stage 45 and the skeletal abnormalities occurring in fore and hind limbs after treatment at all stages of their development.Thus, it appears that the effects of nitrogen mustard on organogenesis demonstrates the existence of a state in the differentiation of the mesoderm that is not revealed by morphological studies.     

Sequential changes in weight of the skeleton and in length of long limb bones of Macaca mulatta.

In a collection of 274 monkeys (Macaca mulatta) the relative weight of the dry, fat-free skeleton, expressed as a proportion of total body weight, increases significantly throughout the gestational period to approximately 6% with only random variation after birth. The weight of the fetal skeleton increases exponentially with age. In the postnatal period the skeletal weight increases asymptotically to adulthood, which is considered to be 6.5 years of age. Equations for estimating skeletal weight are presented. Of four subdivisions of the skeleton, the skul contributes the greatest proportion of total skeletal weight in the fetal stage with the proportion decreasing to adulthood. The contributions of the other subdivisions, postcranial axial, superior limb, and inferior limb, and inferior limb, are nearly equal in the fetal stage, with that of only the inferior limb increasing to adulthood, when it makes up the greatest proportion of total skeletal weight. Until the last third of the gestational period, the humerus is longer than the femur and the radius longer than the tibia. Thereafter, the inferior limbs grow at a faster rate than the superior limbs, resulting in an intermembral index of approximately 95% by birth and less than 90% by adulthood.     

Vitamin A mediated limb deformities in the common Indian toad, Bufo melanostictus (Schneider)

Several types of limb deformities were induced by vitamin A in B. melanostictus. These ranged from total suppression of all the limbs (ectromelia) to partial development of either the forelimb or the hindlimb or both (mesomelia) to reduction or absence of digits in either the forelimbs or hindlimbs or both and absence of long bones in either the forelimbs or hindlimbs or both (phocomelia) or duplication of the hindlimbs (polymelia). All the limb abnormalities were induced in the developing limbs of the tail amputated tadpoles of B. melanostictus following vitamin A treatment, which is all the more interesting. The results suggest that vitamin A induces the above mentioned abnormalities by either switching on or over-expressing or disrupting the limb-specific hox genes by yet unknown mechanisms.     

Ectromelia in Morelet's crocodile from Belize

Two Morelet's crocodiles (Crocodylus moreletii) captured on 21 March 1997 and 20 April 1998 in the New River system, Belize exhibited ectromelia of one forelimb. External and radiograph examination appears to indicate limb agenesis of unknown etiology, as there is no apparent scarring or skeletal trauma. These two individuals represent the only cases of missing limbs from 642 individuals captured in this study and to our knowledge, the first reported cases in Morelet's crocodile. Several factors including age and diet of the reproducing female, extremes in nest conditions (egg incubation temperature and humidity), and exposure to environmental contaminants can cause developmental abnormalities in crocodilians and may have contributed to the condition observed in these animals. Survival rates for hatchling crocodilians are generally low, and embryonic malformations such as ectromelia may constitute an added disadvantage to survival. However, both individuals examined in this study were vigorous and appeared in good condition.     

Hind limb malformations in free-living northern leopard frogs (Rana pipiens) from Maine, Minnesota, and Vermont suggest multiple etiologies

BACKGROUND: Reports of malformed frogs have increased throughout the North American continent in recent years. Most of the observed malformations have involved the hind limbs. The goal of this study was to accurately characterize the hind limb malformations in wild frogs as an important step toward understanding the possible etiologies. METHODS: During 1997 and 1998, 182 recently metamorphosed northern leopard frogs (Rana pipiens) were collected from Minnesota, Vermont, and Maine. Malformed hind limbs were present in 157 (86%) of these frogs, which underwent necropsy and radiographic evaluation at the National Wildlife Health Center. These malformations are described in detail and classified into four major categories: (1) no limb (amelia); (2) multiple limbs or limb elements (polymelia, polydactyly, polyphalangy); (3) reduced limb segments or elements (phocomelia, ectromelia, ectrodactyly, and brachydactyly; and (4) distally complete but malformed limb (bone rotations, bridging, skin webbing, and micromelia). RESULTS: Amelia and reduced segments and/or elements were the most common finding. Frogs with bilateral hind limb malformations were not common, and in only eight of these 22 frogs were the malformations symmetrical. Malformations of a given type tended to occur in frogs collected from the same site, but the types of malformations varied widely among all three states, and between study sites within Minnesota. CONCLUSIONS: Clustering of malformation type suggests that developmental events may produce a variety of phenotypes depending on the timing, sequence, and severity of the environmental insult. Hind limb malformations in free-living frogs transcend current mechanistic explanations of tetrapod limb development.     

Prenatal sonographic diagnosis of skeletal dysplasias. A report of 47 cases

The purpose of this study was to evaluate the foetal sonographic efficiency for prenatal diagnosis of osteochondrodysplasias. Forty-seven prenatal and postnatal cases diagnosed between January 1993 and December 1998 in the referral sonographic centres of Strasbourg were studied. All cases were reviewed retrospectively and the prenatal ultrasound findings and diagnosis were compared to the postnatal or post-mortem diagnosis. Each case was studied by ultrasonographers, geneticists, radiologists, and foetopathologists. Final diagnosis was based on clinical examination, skeletal survey and molecular testing as deemed necessary. Routine screening and dating was the indication for foetal sonography in 72% (32/47) of our cases. The most likely time of diagnosis was between 16 and 24 weeks of gestation (17 out of 47 cases, 36%), which corresponds to the time of foetal anomaly sonographic scan in France. The other cluster of cases (12 among 47, 26%) was disclosed before 16 weeks of gestation. These results illustrate the importance of a detailed evaluation of the limbs during sonographic examinations of first and second trimesters of pregnancy. While the identification of skeletal dysplasias was relatively easy in our study, the ability to make an accurate specific antenatal diagnosis was more difficult. An accurate diagnosis was proposed in 28 of the 47 cases (60%). In 19% of the cases (9/47), the prenatal diagnosis was not accurate; in 21% of the cases (10/47), the prenatal diagnosis was imprecise. In 45 of the 47 cases (96%) prenatal foetal scan correctly predicted the prognosis.     

Perinatal development of endothelial nitric oxide synthase-deficient mice

The purpose of this study was to evaluate the influence of endothelial nitric oxide synthase (eNOS) deficiency on fetal growth, perinatal survival, and limb development in a mouse model with a targeted mutagenesis of the Nos3 gene. Wild-type (Nos3+/+) and eNOS-deficient fetuses (Nos3-/-) were evaluated on Gestational Day (E)15 and E17, and newborn pups were observed on Day 1 of life (D1). The average term duration of pregnancy was 19 days. For the evaluation of postnatal development, a breeding scheme consisting of Nos3+/- x Nos3+/- and Nos3-/- x Nos3-/- mice was established, and offspring were observed for 3 wk. Southern blotting was used for genotyping. No significant differences in fetal weight, crown-rump lengths (CRL), and placental weight were seen between Nos3+/+ and Nos3-/- fetuses on E15. By E17, Nos3-/- fetuses showed significantly reduced fetal weights, CRL, and placental weights. This difference in body weight was also seen throughout the whole postnatal period. In pregnancies of Nos3-/- females, the average number of pups alive on D1 was significantly decreased compared to either E15 or E17. Placental histology revealed no abnormalities. On E15, E17, and D1, Nos3(-/-) fetuses demonstrated focal acute hemorrhages in the distal limbs in 0%, 2.6%, and 5.7%, respectively, of all mutant mice studied on the respective days. Bone measurements showed significantly shorter bones in the peripheral digits of hindpaws of Nos3-/- newborns. We conclude mice deficient for eNOS show characteristically abnormal prenatal and postnatal development including fetal growth restriction, reduced survival, and an increased rate of limb abnormalities. The development of this characteristic phenotype of eNOS-deficient mice dates back to the prenatal development during the late third trimester of pregnancy.