Search results for "linkage"
showing 10 items of 363 documents
Genotype and phenotype analysis of Friedreich's ataxia compound heterozygous patients
2000
Friedreich's ataxia is caused by mutations in the FRDA gene that encodes frataxin, a nuclear-encoded mitochondrial protein. Most patients are homozygous for the expansion of a GAA triplet repeat within the FRDA gene, but a few patients show compound heterozygosity for a point mutation and the GAA-repeat expansion. We analyzed DNA samples from a cohort of 241 patients with autosomal recessive or isolated spinocerebellar ataxia for the GAA triplet expansion. Patients heterozygous for the GAA expansion were screened for point mutations within the FRDA coding region. Molecular analyses included the single-strand conformation polymorphism analysis, direct sequencing, and linkage analysis with FR…
Familial hemiplegic migraine type 2 is linked to 0.9Mb region on chromosome 1q23
2003
Familial hemiplegic migraine (FHM) is a rare autosomal dominant disorder characterized by episodes of transient hemiparesis followed by headache. Two chromosomal loci are associated to FHM: FHM1 on chromosome 19 and FHM2 on chromosome 1q21-23. Mutations of the alpha-1A subunit of the voltage gated calcium channel (CACNA1A) are responsible for FHM1. FHM2 critical region spans 28 cM, hence hampering the identification of the responsible gene. Here, we report the FHM2 locus refining by linkage analysis on two large Italian families affected by pure FHM. The new critical region covers a small area of 0.9Mb in 1q23 and renders feasible a positional candidate approach. By mutation analysis, we ex…
Angiotensin II AT1 receptor gene polymorphism and microalbuminuria in essential hypertension.
2001
The objective of this study was to analyze the relationship of polymorphisms of the angiotensin II AT1 receptor gene with microalbuminuria in a group of young adults with essential hypertension. Essential hypertensives, less than 50 years old, never previously treated with antihypertensive drugs, and in absence of diabetes mellitus were included. Office blood pressure (BP), 24-h ambulatory BP monitoring, urinary albumin excretion (UAE) measurements, and DNA analysis were performed. Polymorphisms of the angiotensin II AT1-receptor gene (A1166C and C573T) were studied by polymerase chain reaction and single-strand conformation polymorphism techniques. One hundred eighty-three patients, 49 (27…
A Putatively Functional Haplotype in the Gene Encoding Transforming Growth Factor Beta-1 as a Potential Biomarker for Radiosensitivity
2011
Purpose To determine whether genetic variability in TGFB1 is related to circulating transforming growth factor-β1 (TGF-β1) plasma concentrations after radiotherapy and to radiosensitivity of lymphoid cells. Patients and Methods Transforming growth factor-β1 plasma concentrations ( n = 79) were measured in patients 1 year after radiotherapy and chromosomal aberrations ( n = 71) ex vivo before therapy start. Furthermore, TGF-β1 secretion and apoptosis were measured in isolated peripheral blood mononuclear cells of 55 healthy volunteers. These phenotypes were analyzed in relation to five germline polymorphisms in the 5′ region of the TGFB1 gene. Because of high linkage disequilibrium, these fi…
Further evidence of genetic heterogeneity in familial essential tremor.
2007
Familial essential tremor (FET) is a common hereditary movement disorder with phenotypic variability and genetic heterogeneity. To date, linkage analyses revealed three loci associated to essential tremor (ET) (ETM1 on 3q13, ETM2 on 2p22-25, and a locus on 6p23). We performed a genetic analysis of these candidate chromosomal regions in a fifth-generation Italian kindred with autosomal-dominant ET. Of the 22 clinically evaluated family members, nine were affected by ET. The genetic study indicates that the ET in this family is not associated to any of the known ET loci. These findings support evidence of further genetic heterogeneity for such disease. (C) 2007 Elsevier Ltd. All rights reserv…
Germline and somatic mutations in the tyrosine kinase domain of the MET proto-oncogene in papillary renal carcinomas.
1998
Hereditary papillary renal carcinoma (HPRC) is a recently recognized form of inherited kidney cancer characterized by a predisposition to develop multiple, bilateral papillary renal tumours. The pattern of inheritance of HPRC is consistent with autosomal dominant transmission with reduced penetrance. HPRC is histologically and genetically distinct from two other causes of inherited renal carcinoma, von Hippel-Lindau disease (VHL) and the chromosome translocation (3;8). Malignant papillary renal carcinomas are characterized by trisomy of chromosomes 7, 16 and 17, and in men, by loss of the Y chromosome. Inherited and sporadic clear cell renal carcinomas are characterized by inactivation of b…
Cholinesterase variants: rapid characterisation by PCR/SSCP and evidence for molecular homogeneity.
1995
We have applied the technique of PCR-SSCP (polymerase chain reaction-single stranded conformation polymorphism) to characterise the molecular basis of cholinesterase deficiency and variants in a Jordanian family. PCR-SSCP proved to be a quick and sensitive method of screening cholinesterase variants in a clinical setting. An AG insertion at position 351 was found to cause a silent allele, for which the parents were heterozygous and three children homozygous. In addition, the father and two sons were heterozygous for an A to G transition at position 209, known to cause the dibucaine resistant variant. No linkage to the K variant was found, which has been reported previously in white populati…
Markers of T Lymphocyte Activation in HLA-B8, DR3 Positive Individuals
1990
Many autoimmune diseases are associated in Caucasians with HLA-B8 and/or HLA-DR3 antigens. There is evidence that bearers of these antigens may display significant changes in immune parameters when compared to individuals not having these antigens. Recently, increased numbers of blood activated T lymphocytes have been reported in the majority of these diseases. The increase in activated blood T lymphocytes is paradoxically characterized by an in vitro impairment of T cell activation. Particularly, an inadequate production of interleukins has been observed. We have studied blood levels of activated T cells in HLA-typed, healthy subjects. The results show that the percentage of activated T ce…
Statistical colocalization of monocyte gene expression and genetic risk variants for type 1 diabetes
2012
One mechanism by which disease-associated DNA variation can alter disease risk is altering gene expression. However, linkage disequilibrium (LD) between variants, mostly single-nucleotide polymorphisms (SNPs), means it is not sufficient to show that a particular variant associates with both disease and expression, as there could be two distinct causal variants in LD. Here, we describe a formal statistical test of colocalization and apply it to type 1 diabetes (T1D)-associated regions identified mostly through genome-wide association studies and expression quantitative trait loci (eQTLs) discovered in a recently determined large monocyte expression data set from the Gutenberg Health Study (1…
No association of alcohol dependence with HOMER 1 and 2 genetic variants.
2010
Several lines of evidence indicate that alterations of the central cortico-accumbens glutamate pathway are involved in the development and maintenance of alcohol- and substance-use disorders. The HOMER protein family is encoded by 3 genes HOMER (1–3) which are components of the excitatory postsynaptic density complex and function to modulate synaptic activity by the regulation of glutamate signaling. HOMER 1 and 2 have been reported to contribute to chronic alcohol-induced long-term neurochemical changes in the endogenous reward system. Data from animal models suggest a potential role of the Homer protein family in the development of alcohol and substance use. The aim of this study is to as…