Carrier detection for hemophilia B: evaluation of multiple polymorphic sites

DNA analysis was performed in families with hemophilia B. Restriction fragment length polymorphisms (RFLPs) produced by endonucleases Taql, Xmnl, and Ddel were studied by two factor IX genomic probes, F9(VIII) and F9(XIII). Fifty-seven subjects from ten families were investigated; of them, 31 were carriers (11 obligate and 20 potential). Of the potential carriers, ten displayed laboratory features allowing for a phenotypic diagnosis of heterozygosity. Segregation analysis of the markers was informative in 19/20 potential carriers, which belong to nine of the ten studied families. Among the potential carriers, Taql allowed the carriership assessment in 15 (78.9%), Xmnl in 15 (94.7%), and Ddel in two (10.4%). Diagnosis was not possible in one family since a homozygosity in the key individuals with all the employed enzymes (Taql, Xmnl, Ddel, + BamHI) was found. Hemophilia B syndrome in two families likely results from a new mutation. In one family, a first-trimester prenatal diagnosis was performed. The use of RFLP analysis allowed us to improve genetic counseling as compared with the phenotypic evaluation by clotting factor assays. Indeed, evaluation of RFLP increased by 26% the carriership assessment of the potential carriers of the hemophilia B trait.     

Carrier analysis of a moderately affected haemophilia B family.

Here we report the successful genetic diagnosis of a pregnant caucasian female patient whose family has a history of moderate haemophilia B. While restriction fragment length polymorphism (RFLP) analysis was not informative, nucleotide sequencing of the factor IX genes of the patient's family members determined that her mother and one of her two sisters were carriers of the mutation C31008T, which causes a Thr296Met transition. In contrast, the pregnant female herself and her other sister were found to carry only normal alleles. Plasma factor IX activity and antigen levels supported these findings.     

Carrier detection in the Wiskott Aldrich syndrome

The Wiskott-Aldrich syndrome (WAS) is an X-linked recessive disease characterized by immunodeficiency and severe thrombocytopenia in affected males, but no demonstrable clinical abnormalities in carrier females. Through analysis of the methylation patterns of X-linked genes that display restriction fragment length polymorphisms (RFLPs), we studied the pattern of X-chromosome inactivation in various cell populations from female relatives of patients with WAS. The peripheral blood T cells, granulocytes, and B cells of eight obligate WAS carriers were found to display specific patterns of X-chromosome inactivation clearly different from these of normal controls. Thus, carriers of WAS could be accurately identified using this analysis.     

The Prognosis of the Healthy HBsAg Carrier State

Thirty-six persons found to be healthy HBsAg carriers by routine donor screening from 1970 to 1973 were offered a follow-up examination in 1978. A total of 21 out of the 34 still living carriers were reexamined clinically, serologically, and biochemically. Seventeen of the 20 still HBsAg-positive carriers had anti-HBe, and 2 were HBeAg-positive. Liver biopsy in these two carriers showed chronic persistent hepatitis. No biochemical abnormalities were found in any but one who was HBeAg-positive and one who was negative for both HBeAg and anti-HBe. Anti-HBc titers varied between 1:3,600 and 1:83,000. Circulating immune complexes were demonstrated in 30% of the healthy HBsAg carriers. On the basis of 5-8 years' follow-up it is concluded that the healthy HBsAg carrier state is a benign condition that has not affected the carrier's quality of life. Progression to a severe, chronic liver disease was not observed in any of the healthy carriers. The importance and nature of circulating immune complexes in healthy HBsAg carriers are unknown and need further investigation.     

New FACTOR IX linked marker alleles in African Haemophilia B patients.

Three markers, one restriction length polymorphism (RFLP) (MseI) and two microsatellite markers (Intron 1 and 3'UTR), linked to the FACTOR IX gene, were assessed for the purpose of genetic testing for Haemophilia B families in South Africa. This was carried out using seven Haemophilia B families and fifty random control samples. We observed five new alleles for the Intron 1 marker within the black control and patient sample groups, and informativity in 89% (8/9) of all carrier females for at least one of the three markers observed. These markers are useful for carrier detection and prenatal diagnosis of Haemophilia B in the great majority of South African black and white families.     

Carrier detection in ornithine transcarbamylase deficiency

We have studied six known heterozygotes for ornithine transcarbamylase (McKusick 31125; OTC) deficiency. All had abnormal results when tested by measurement of urine orotic acid after protein loading. Duodenal mucosa OTC assay detected fewer of the known heterozygotes but was a useful supplementary test. Urine orotic acid excretion after protein loading is influenced by age and results from women being tested must be compared with those from controls of appropriate age.     

Carrier detection in factor VII congenital deficiency

Thirty obligate and 28 possible carriers of factor VII congenital deficiency, belonging to 16 families, were studied in relation to the immunological variants to which the kindreds belonged, namely, VII+, VIIR and VII-. Factor VII activity and antigen determinations in these subjects formed two phenotypical patterns: a discrepant pattern characterized by a low ratio activity/antigen present in VII+ heterozygotes, and a non-discrepant pattern (normal ratio activity/antigen) which is present in the VII- and VIIR variants. In the first genetic variant the detection of carriers can be performed using the ratio VII:C/VII:Ag. In the other variant, which accounts for the vast majority of heterozygotes, the distribution of the carriers' factor VII is so widespread that a large overlap results between these subjects and the normals. The application of a probabilistic calculation performed by combining the actual values of factor VII:C and the genetic probability of carriership using Fisher's linear discriminant analysis, makes discrimination between carriers and normals easier.     

Carrier detection and prenatal diagnosis by intron 22 inversion analysis of the factor VIII gene

Summary In approximately 50% of severe haemophilia A patients the mutation is present in the form of a large chromosomal disruption in the factor VIII gene; this disruption is described as an inversion. It results in the physical breakage and separation of exons 1-2 and exons 23-26 of the factor VIII gene.     

Molecular genetics of essential hypertension

Hypertension is a major public health problem in the developing as well as in developed countries due to its high prevalence and its association with coronary heart disease, renal disease, stroke, peripheral vascular disease, and related disorders. Essential hypertension (EH) is the most common diagnosis in this disease, suggesting that a monocausal etiology has not been identified. However, a number of risk factors associated with EH have also been identified such as age, sex, demographic, environmental, genetic, and vascular factors. Recent advances in molecular biological research had achieved clarifying the molecular basis of Mendelian hypertensive disorders. Molecular genetic studies have now identified mutations in several genes that cause Mendelian forms of hypertension in humans. However, none of the single genetic variants has emerged from linkage or association analyses as consistently related to the blood pressure level in every sample and in all populations. Besides, a number of polymorphisms in candidate genes have been associated with differences in blood pressure. The most prominent candidate has been the polymorphisms in the renin–angiotensin–aldosterone system. In total, EH is likely to be a polygenic disorder that results from inheritance of a number of susceptibility genes and involves multiple environmental determinants. These determinants complicate the study of blood pressure variations in the general population. The complex nature of the hypertension phenotype makes large-scale studies indispensable, when screening of familial and genetic factors was intended. In this review, recent genetic studies exploring the molecular basis of EH, including different molecular pathways, are highlighted.     

日本血吸虫种群的遗传标志应用研究进展

日本血吸虫种群遗传结构的研究有助于更好地理解日本血吸虫病的传播和感染途径,这对于血吸虫病的监控与防治以及对其疫苗的发展都将具有重要的意义。近年来,随着分子遗传学理论与实验技术的发展,在日本血吸虫种群遗传学上取得了一些重大的研究进展。多种遗传标志如：限制性片段长度多态性、线粒体DNA、微卫星等在日本血吸虫种群遗传学上均得到了很好的应用,该文就应用于日本血吸虫的种群遗传学上主要的遗传标志作一综述。     

Biomarkers for detection of alcohol consumption in liver transplantation

Alcoholic liver disease is an established, yet controversial, indication for liver transplantation. Although an abstinence period of up to 6 mo prior to transplantation is mandatory, alcohol relapse after transplantation is a common event. In case of recurrence of heavy drinking, graft survival is significantly impaired. Guidelines on detection and surveillance of alcohol consumption in this patient cohort are lacking. This review summarizes the challenge of patient selection as well as the current knowledge on established and novel alcohol biomarkers with special focus on liver transplant candidates and recipients.     

狂犬病毒HEP-dG株的拯救

目的筛选免疫原性高、致病性低的狂犬病疫苗候选株。方法应用反向遗传技术,在狂犬病毒弱毒株HEP-Flury株全基因组3'-N-P-M-G-L-5'的假基因区域(G与L之间),插入一个G基因,构建携带双G基因的全长感染性克隆,其与辅助质粒共转染BHK-21细胞,盲传十代,用荧光抗体和RT-PCR鉴定病毒。结果成功获得携带双G基因的狂犬病毒HEP-dG株,该病毒在BHK-21细胞中稳定生长,其病毒滴度达到1010FFU/mL。结论HEP-dG株会为研制高效的狂犬病病毒基因工程口服疫苗提供了良好的疫苗候选株。     

慢性呼吸衰竭患者血气分析与凝血三项检测的相关性研究

目的探讨慢性呼吸衰竭患者凝血三项及与血气分析相关性。方法对28例慢性呼吸衰竭患者治疗前后血气分析、凝血三项及28例对照组的凝血三项分别进行测定。结果血浆纤维蛋白原、部分活化凝血活酶时间、凝血酶原时间水平在慢性呼吸衰竭患者明显升高,治疗后明显下降;血浆纤维蛋白原与血氧分压呈负相关,与血二氧化碳分压呈正相关。结论慢性呼吸衰竭患者存在高凝状态,临床治疗中适当的抗凝治疗对控制慢性呼吸衰竭患者的病情可能有益。     

胃粘膜石蜡切片PCR法检测幽门螺杆菌

目的建立从石蜡包埋的胃粘膜标本中扩增ＨｐＤＮＡ的聚合酶链反应（ＰＣＲ）．方法以一对Ｈｐ特异的寡核苷酸为引物，采用双扩增ＰＣＲ扩增Ｈｐ１６ＳｒＲＮＡ基因，并与常规检测方法进行了比较．结果双扩增ＰＣＲ检出的最小ＨｐＤＮＡ量为００１ｐｇ．用该方法检测十二指肠溃疡患者２０例石蜡包埋的胃粘膜标本，并与尿素酶试验、细菌培养、Ｗａｒｔｈｉｎ＿Ｓｔａｒｒｙ银染色及ＰＣＲ对新鲜胃粘膜标本的检测作比较，结果１８例患者上述五项检测结果一致，２例尿毒酶试验、银染色及ＰＣＲ对新鲜胃粘膜标本的检测呈阳性的患者，采用双扩增ＰＣＲ对石蜡包埋标本的检测未发现ＨｐＤＮＡ．ＰＣＲ对石蜡包埋标本及新鲜胃粘膜标本的检测有显著相关性．结论双扩增ＰＣＲ为分子水平上Ｈｐ感染的回顾性研究提供一有利工具．     

Genetic variation in the hypothalamic pathways and its role on obesity

Over recent decades, the prevalence of obesity has increased dramatically worldwide. Although this epidemic is mainly attributable to modern (western) lifestyle, multiple twin and adoption studies indicate the significant role of genes in the individual's predisposition to becoming obese. As the hypothalamus plays a central role in controlling body weight, its regulatory circuits may represent a crucial system in the pathogenesis of the disorder. Genetic variations in genes in the hypothalamic pathways may therefore contribute to the susceptibility for obesity in humans and animals.
We summarize current knowledge on the physiological role of the hypothalamus in body-weight regulation and review genetic studies on the hypothalamic candidate genes in relation to obesity. Together, data from functional and genetic studies as well as the new, common, obesity loci identified in genome-wide association scans support an important role for the hypothalamic genes in predisposing to obesity. However, findings are still inconclusive for many candidate genes. To improve our understanding of the genetic architecture of common obesity, we suggest that specific obesity phenotypes should be considered and different analytical approaches used. Such studies should consider multiple genes from the same physiological pathways, together with environmental risk factors.     

Haemophilia A: Carrier detection by DNA analysis

Summary From 46 families of predominantly German origin, afflicted with haemophilia A, 178 females were tested for carrier status. Two polymorphic restriction endonuclease sites, the extragenic marker locus DXS 52 (St 14 probe) and the intragenic Bcl I RFLP were investigated in these families. In some cases the results were corroborated by identifying (i) deletions within the factor VIII:C gene and (ii) eliminating a restriction endonuclease site. Two new alleles of the DXS 52 marker locus were found. According to this strategy, 27 women were classified as carriers and 74 as non-carriers. Forty-six women were classified as carriers according to pedigree analysis. Twenty-five females of families with sporadic cases and 6 test persons, who had mothers who where homozygous for the marker alleles, were diagnosed by additional use of conventional carrier detection.     

Carrier detection and prenatal diagnosis of hemophilia in developing countries

Hemophilia A and B, inherited as X-linked recessive traits, are the most common hereditary hemorrhagic disorders caused by a deficiency or dysfunction of coagulation factor VIII (FVIII) or FIX, respectively. Hemophilia is prevalent worldwide, without ethnic or geographic limitations, and remains a life-threatening and often disabling condition. Advances in molecular medicine in this century have markedly improved hemophilia treatment. However, management is still largely inadequate in developing countries. Therefore, carrier detection and prenatal diagnosis remain the key steps for the prevention of the birth of children with hemophilia in developing countries where patients with this coagulation disorder rarely live beyond childhood. Carrier detection and prenatal diagnosis are possible by direct or indirect genetic analysis of the F8 or F9 genes. In countries with more advanced molecular facilities and higher budget resources, the most appropriate choice in general is a direct strategy for mutation detection by prescreening techniques or direct mutation detection. However, in countries with limited facilities and low budget resources, carrier detection and prenatal diagnosis are usually performed by linkage analysis with genetic markers. This article suggests the possibilities of genetic diagnosis and a feasible strategy for carrier detection and prenatal diagnosis in families with hemophilia A and B in developing countries.     

Carrier detection and prenatal diagnosis in haemophilia A and B

Sixty probable carriers of haemophilia from 25 families were studied by using coagulation phenotype and DNA analysis: 33 with haemophilia A and 27 with haemophilia B. Coagulation phenotype was based on factor VIII/IX assay and DNA analysis on the examination of restriction fragment length polymorphisms (RFLPs) within and closely linked to factor VIII or IX: 3 RFLP for factor VIII and 3 for factor IX. The comparison between the coagulation phenotype and RFLP analysis showed the misclassification of 15 females (6 for haemophilia A and 9 for haemophilia B). Four prenatal haemophilia A diagnosis were made by DNA analysis of chorionic villi, taken with a transcervical trophoblastic biopsy, between the 18th and the 11th week.