母女猫叫综合征患者的遗传分析

猫叫综合征患者不仅可以活到成年, 而且可有生育能力,可将缺失染色体直接传给其子女使其患同样的疾病。早产是该综合征重要临床表现之一。     

猫叫综合征一家系高分辨染色体分析

本文采用高分辨染色体技术,对一例猫叫综合征患儿及其家系进行了分析,结 果提示,猫叫综合征染色体关键片段位于5p15.3→5pter。     

VHL综合征遗传学研究

VHL综合征(von Hippel-Lindau syndrome,VHL;MIM 193300)是一种常染色体显性遗传的多系统肿瘤综合征,最常见临床表现是视网膜或中枢神经系统(central nervous system,CNS)血管母细胞瘤.CNS血管母细胞瘤和肾细胞癌(renal cell carcinoma,RCC)的并发症是VHL患者最主要的死因.VHL综合征主要因VHL基因(the vonHipple-Lindau gene,VHL)突变所致,细胞周期素D1基因(the cyclin D1 gene,CCND1)突变和蛋白异常也可能参与其发生.目前已建立了多个VHL基因缺陷动物模型.在此就VHL综合征的遗传学研究进展作一概述.     

六例性反转综合征患者的分子遗传学分析

对六例性反转综合征患者(3例XX男性)(3例XY女性)用Y-特异性DNA探针进行了Southern印迹杂交分析,并用PCR技术扩增了SRY基因部分序列。结果表明,1例XX男性缺乏源于Y染色体的杂交信号,也无SRY基因;其余2例XX男性和3例XY女性都检测到Yp-DNA序列和SRY基因。这对进一步阐明性反转综合征的病因和SRY基因的作用机制具有重要意义。     

脆性X综合征的分子遗传学研究进展

脆性X综合征是常见的遗传性智力低下性疾病,其发病率高,临床表现复杂,遗传规律独特,对脆性X 综合征的发病机理和脆性X综合征筛查与诊断方法等方面的一些研究进展进行了综述.     

一个中国Gilbert综合征家系的遗传学分析

对一个中国汉族Gilbert综合征遗传家系致病基因突变位点进行鉴定,以期了解该病的分子遗传学基础。首先提取先证者基因组DNA,PCR扩增尿苷二磷酸葡萄糖醛酸转移酶UGT1A1基因的5个外显子,以琼脂糖电泳鉴定PCR产物,纯化后直接测序鉴定。基因扫描显示,与血清胆红素水平密切相关的UGT1A1基因在第1和第5外显子存在纯合突变,而 UGT1A1基因启动子区域和内含子/外显子剪接边界位点序列未检测到突变。进一步对其他家系成员该基因的相应位点进行突变检测,结果显示他们在第1和第5外显子也存在杂合突变,其中还有两个成员在启动子区域检测到(TA)插入突变。对家系成员未抗凝新鲜血液进行生化检测证实了基因突变分析的结果。综合以上结果发现该家系三种突变并存,致病因素为第1和/或第5外显子突变,为显性遗传,两种突变位点纯合导致先证者出现严重胆红素代谢功能障碍。该家系因此成为Gilbert综合征突变位点及其致病机理研究的一个典型临床病例。     

抽动秽语综合征遗传学研究

抽动秽语综合症(Gilles de la Tourette’s syndrome,GTS,TS)是一种慢性复杂性神经精神障碍,多起病于儿童期,以多发性运动性抽动伴不自主发声为主要临床表现,并伴多种并发症及神经行为障碍.目前已有大量关于TS遗传学研究报道,但其主要遗传学基础尚未鉴定.在此就抽动秽语综合征的遗传学研究做一介绍.     

青光眼的分子遗传学研究

青光眼是由于眼压升高而引起视乳头损害、视网膜神经纤维层缺损和视野缺损的一种致盲性眼病 .对不同类型青光眼的分子遗传学研究进展 ,主要是基因定位和基因克隆进展及其展望进行了综述 .     

不宁腿综合征遗传学研究进展

不宁腿综合征(Restless legs syndrome, RLS)遗传学研究近年来获得了许多重要的进展, 极大地丰富了对于这种疾病分子机制的认识。RLS是一种常见的复杂疾病, 几个遗传流行病学和双生子研究对RLS遗传组分进行了剖析, 说明RLS是一个遗传性很强的性状, 其遗传力约为50%。采用基于模型的连锁分析方法或者是不依赖于模型的连锁分析方法目前已定位了5个重要的RLS疾病连锁位点: 12q13-23, 14q13-21, 9p24-22, 2q33和20p13, 为定位克隆RLS致病基因或者易感基因提供了连锁图谱。最新基于高通量的SNPs分型平台开展的全基因组分析确立3个与RLS显著关联的区域: 6p21.2, 2p14和15q23。文章结合作者近年来从事不宁腿综合征遗传学的研究工作, 对该领域的重要成果进行了汇总和评述。     

导诊服务台对患者咨询问题分析及对策

门诊作为医院的重要窗口,是对病人进行早期有效诊治的重要场所,是确保医疗和护理质量的首要环节,同时门诊也是各种病人高度集中的场所。门诊的环境嘈杂、拥挤,人流动性大,且以患者为主。由于患者有病痛,行动不便,环境不熟悉,对医疗工作程序不了解等原因,均会加重就诊过程中的不便和精神负担。因此做好导医工作,为患者提供咨询服务,方便患者就诊是门诊护理工作的重要环节之一。现就本院患者对导诊服务台所咨询的问题进行随机统计分析,并提出相应对策。     

Genetics of cat hemoglobins: A quantitative polymorphism

Blood samples from domestic cats, representing the parents (26) and offspring (91) from 33 matings, were analyzed to determine the proportions of hemoglobins A and B. Evidence is presented that the proportions of the two hemoglobins are genetically determined and that cats may be divided into three groups on the basis of this characteristic. Family data and Hardy-Weinberg analysis support the hypothesis that the three groups represent the possible combinations of an allelic gene pair. In an attempt to explain the observed phenotypic differences, possible points of action of this gene pair are discussed, including effects on rates of synthesis or epigenetic modification of globin chains.     

RFLP analysis of cry1 and cry2 genes of Bacillus thuringiensis isolates from India

The PCR-RFLP method has been useful for detection of known genes and identification of novel genes. In the present study, degenerate primers were designed from five groups of cry1 genes for PCR-RFLP analysis. Bacillus thuringiensis (Bt) isolates from different regions were evaluated for PCR amplification of various cry1 genes using newly designed primers and cry2 genes using reported primers. PCR analysis showed an abundance of cry1A genes and especially cry1Ac genes in isolates from all regions. RFLP analysis revealed the presence of multiple cry1A genes in isolates from central and southern regions. Unique digestion patterns of cry1A genes were observed in isolates from each region. Few of the isolates represented a digestion pattern of cry1A genes that did match to any of the known cry1A genes. RFLP analysis suggested an abundance of cry2Ab along with a novel cry2 gene in Bt isolates from different regions of India. Sequence analysis of the novel cry2 gene revealed 95% sequence identity to cry2Ab and cry2Ah genes. Phylogenetic analysis revealed that the novel cry2 gene could have diverged earlier than the other cry2 genes. Our results encourage finding of more diverse cry2 genes in Bt isolates. Rarefaction analysis was used to compare cry1A gene diversity in isolates from different soil types. It showed a higher degree of cry1A gene diversity in isolates from central region. In the present study, we propose the use of novel degenerate primers for cry1 genes and the PCR-RFLP method using a single enzyme to distinguish multiple cry1A and cry2 genes as well as identify novel genes.     

Fertility and genetic counseling in Turner syndrome

We report three cases of Turner syndrome 45,X/46,XX with spontaneous menstruations. Two patients had together four pregnancies with a normal girl, a malformed boy and two miscarriages. The outcome of the pregnancy in such a women is discussed with a review of the literature.     

Genetic counseling and the caudal regression syndrome

It has been published about 500 cases of caudal regression (sacral agenesis) of which 12 are undoubtly familial. In most of the non familial cases an aetiology is not demonstrable except the cases related to maternal diabetes and/or insulin treatment. A genetic control of the caudal regression is implicit in the familial transmission. Three sporadic new cases are reported and, at the occasion of the genetic counselling we analyse the 8 well reported genealogies. Among 133 subjects, 72 show some evidences of caudal regression. This is compatible with a pattern of autosomic dominant transmission. The analogy with the caudal regression anomaly of the mouse, in which the role of genes located closely to the histocompatibility system is demonstrated, evokes such a relation in the human with the major histocompatibility system. If true, this may be used as a genetic marker, especially for early antenatal diagnosis.     

Genetics of Patau's syndrome (an analysis of 59 families)

Different parental translocations were observed in 11 out of 59 families where a child with Patau's syndrome was born. All cases, except for one with t(13; 18) (q14; q23) in the father, revealed the Robertsonian translocations. In most cases there were t(13; 14). The t(13; 15) and t(13; 13) translocations were detected in one mother each. The latter woman bore three babies with Patau's syndrome. One boy in this series had trisomy 13 and sporadic translocation t(2; 22) (q31; q13) simultaneously.     

Genetic counseling in Usher syndrome: linkage and mutational analysis of 10 Colombian families

Usher Syndrome (US), an autosomal recessive disease, is characterized by retinitis pigmentosa (RP), vestibular dysfunction, and congenital sensorineural deafness. There are three recognized clinical types of the disorder. In order to improve genetic counseling for affected families, we conducted linkage analysis and DNA sequencing in 10 Colombian families with confirmed diagnosis of US (4 type I and 6 type II). Seventy-five percent of the US1 families showed linkage to locus USH1B, while the remaining 25% showed linkage to loci USH1B and USH1C. Among families showing linkage to USH1B we found two different mutations in the MYO7A gene: IVS42-26insTTGAG in exon 43 (heterozygous state) and R634X (CGA-TGA) in exon 16 (homozygous state). All six US2 families showed linkage to locus USH2A. Of them, 4 had c.2299delG mutation (1 homozygote state and 3 heterozygous); in the remaining 2 we did not identify any pathologic DNA variant. USH2A individuals with a 2299delG mutation presented a typical and homogeneous retinal phenotype with bilateral severe hearing loss, except for one individual with a heterozygous 2299delG mutation, whose hearing loss was asymmetric, but more profound than in the other cases. The study of these families adds to the genotype-phenotype characterization of the different types and subtypes of US and facilitates genetic counseling in these families. We would like to emphasize the need to perform DNA studies as a prerequisite for genetic counseling in affected families.