Search results for "Heterozygote"
showing 10 items of 240 documents
Study of the Association with -330T/G IL-2 in a Population of Centenarians from Centre and South Italy.
2005
Immune response in elderly is characterised by a progressive loss of the ability to cope environmental stressors with a characteristic remodelling of cytokine network. One of the data constantly reported in literature is the decrease of IL-2 production. An IL-2 central role in the reconstitution of T cell function in vitro is largely documented. Studies on a T → G polymorphism at - 330 nt of IL-2 gene promoter region have demonstrated that T lymphocytes from 330GG homozygous subjects are able to produce in vitro higher amount of IL-2, than -330TG heterozygous or -330TT homozygous subjects. As a genetic background conditioning the maintaining of an efficient immune response would exert posit…
Evidence for an Association between Post-Fledging Dispersal and Microsatellite Multilocus Heterozygosity in a Large Population of Greater Flamingos
2013
10 pages; International audience; DISPERSAL CAN BE DIVIDED INTO THREE STAGES: departure, transience and settlement. Despite the fact that theoretical studies have emphasized the importance of heterozygosity on dispersal strategies, empirical evidence of its effect on different stages of dispersal is lacking. Here, using multi-event capture-mark-recapture models, we show a negative association between microsatellite multilocus heterozygosity (MLH; 10 loci; n = 1023) and post-fledging dispersal propensity for greater flamingos, Phoenicopterus roseus, born in southern France. We propose that the negative effects of inbreeding depression affects competitive ability and therefore more homozygous…
Characterization of the repeat expansion size in C9orf72 in amyotrophic lateral sclerosis and frontotemporal dementia
2013
Hexanucleotide repeat expansions within the C9orf72 gene are the most important genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The difficulty of developing a precise method to determine the expansion size has hampered the study of possible correlations between the hexanucleotide repeat number and clinical phenotype. Here we characterize, through a new non-radioactive Southern blot protocol, the expansion size range in a series of 38 ALS and 22 FTD heterozygous carriers of >30 copies of the repeat. Maximum, median and modal hexanucleotide repeat number were higher in ALS patients than in FTD patients (P < 0.05 in all comparisons). A higher median numb…
Meiosis in translocation heterozygotes in the mosquito Culex pipiens.
1971
Adult Culex pipiens males irradiated with both X-rays and neutrons were crossed to untreated females and F1-egg rafts were checked for dominant lethality. F1-progenies were outcrossed with normal individuals in order to obtain lines with inherited semisterility. From a total of 120 lines that showed a certain amount of sterility 12 lines were studied cytologically. 10 lines showed reciprocal chromosome exchanges.—At late pachytene and diplotene cross configurations with large asynaptic regions at the center of the cross are obligatory. Bivalents, chains of three, chains of four, and ring configurations are present at metaphase and anaphase I. The different frequencies of the occurrence of s…
A high incidence of meiotic silencing of unsynapsed chromatin is not associated with substantial pachytene loss in heterozygous male mice carrying mu…
2009
Meiosis is a complex type of cell division that involves homologous chromosome pairing, synapsis, recombination, and segregation. When any of these processes is altered, cellular checkpoints arrest meiosis progression and induce cell elimination. Meiotic impairment is particularly frequent in organisms bearing chromosomal translocations. When chromosomal translocations appear in heterozygosis, the chromosomes involved may not correctly complete synapsis, recombination, and/or segregation, thus promoting the activation of checkpoints that lead to the death of the meiocytes. In mammals and other organisms, the unsynapsed chromosomal regions are subject to a process called meiotic silencing of…
Cathepsin C gene: First compound heterozygous patient with Papillon-Lefèvre syndrome and a novel symptomless mutation.
2001
Papillon-Lefevre syndrome (PLS) has recently been shown to be caused by mutations in the cathepsin C gene resulting in periodontal disease and palmoplantar keratosis. Thirteen different homozygous mutations have been characterised in PLS patients of different ethnic origin. In the present paper, a PLS patient is described who carries two novel mutations (706G>T and 872G>A) in the paternal and maternal chromosomes, respectively. This is the first compound patient described so far. In addition, a novel symptomless mutation (458C>T) in the cathepsin C gene is described in three homozygous individuals. Thus, not all mutations should be considered as a cause of disease, whether case studies or g…
Hydrops, fetal pleural effusions and chylothorax in three patients with CBL mutations.
2014
Fetal hydrops, fetal pleural effusions, hydrothorax, and chylothorax, may be associated with various genetic disorders, in particular with the Noonan, cardio-facio-cutaneous and Costello syndromes. These syndromes, collectively called RASopathies, are caused by mutations in the RAS/MAPK pathway, which is known to play a major role in lymphangiogenesis. Recently, germline mutations in the Casitas B-cell lymphoma (CBL) gene were reported in 25 patients and of these, 20 had juvenile myelomonocytic leukemia (JMML). The disorder was named "CBL syndrome" or "Noonan syndrome-like disorder with or without juvenile myelomonocytic leukemia" (NSLL). To date, prenatal abnormalities have not been report…
Frontotemporal dementia: the post-tau era.
2006
As scientists have begun to decipher the molecular genetic bases of hereditary frontotemporal dementia (FTD), it has become clear that the biology of these human neurodegenerative diseases has a complexity not previously suspected. FTD has been found to be linked to several chromosomal loci including those in chromosome 9, chromosome 17, and chromosome 3. The article by Guyant-Marechal et al. in this issue of Neurology reports the clinical, pathologic, and molecular characteristics of a form of FTD associated with inclusion body myopathy and Paget disease of the bone observed in members of two families and expands our knowledge on genetically determined FTD.1 The disorder is associated with…
Leigh syndrome due to compound heterozygosity of dihydrolipoamide dehydrogenase gene mutations. Description of the first E3 splice site mutation.
2003
Item does not contain fulltext A boy with recurrent episodes of hypoglycaemia and ataxia, microcephaly, mental retardation, permanent lactic acidaemia, intermittent 2-oxoglutaric aciduria as well as elevation of serum branched chain amino acids was diagnosed with dihydrolipoamide dehydrogenase (E3) deficiency. Analysis of genomic DNA revealed compound heterozygosity for two novel mutations: I393T in exon 11, located at the interface domain of the protein and possibly interfering with its dimerisation, and IVS9+1G>A located at a consensus splice site. A heterozygous polymorphism was also detected. In the patient's cDNA the I393T mutation and the polymorphism appeared to be homozygous, indica…
Inbreeding depression and male fitness in black grouse
2002
The male lifetime lekking performance was studied, and related to inbreeding-outbreeding in a wild population of black grouse (Tetrao tetrix) in central Finland between 1989 and 1995. Inbreeding was measured as the mean heterozygosity and mean d(2) of 15 microsatellite loci. We found a significantly positive relationship between mean d(2) and lifetime copulation success (LCS), while the relationship between heterozygosity and LCS was close to significant. We also found that males that never obtained a lek territory had significantly lower mean heterozygosity than males that were observed on a territory at least during one mating season in their life. Furthermore, among males that were succe…