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Biomedical subjects

N Akar

Publications and source records attributed to N Akar.

At least 55 records · Page 3Linked to original sources
PubMed2000

Effect of methylenetetrahydrofolate reductase 677 C-T, 1298 A-C, and 1317 T-C on factor V 1691 mutation in Turkish deep vein thrombosis patients.

Possible effect of three common mutations in (MTHFR 677 C-T; 1317 T-C; 1298 C-A) and FV 1691 G-A mutation was studied in Turkish patients with thrombosis and compared with normal controls. The case-control study included 68 patients with the diagnosis of deep vein thrombosis and 66 controls, consecutively selected among subjects without personal and familial history of atherothrombosis. Patients with deep vein thrombosis were selected if Doppler ultrasonography was positive. Only, the comparison of factor V 1691 G-A mutation revealed statistically significant difference in control (6.06%) and deep vein thrombosis (23.5%) group. Risk assessment of double prothrombotic gene alterations revealed only FV 1691 G-A mutation as an independent risk factor for thrombosis (odds ratio 4.7 [1.5-15.0]), but our data suggested that MTHFR 677 has effect on its own (odds ratio 1.97 [0.6-2.7]) but may have synergy with FV 1691 G-A (odds ratio 8.12 [2.0-25.3]). However, MTHFR 1298 A-C and 1317 T-C does not have any effect; furthermore, being heterozygote at two different loci or homozygosity at least in a locus for 677 and 1298 revealed a significant increase (odds ratio 9 and 24 [1.3-59.3 and 2.3-240.3]) between these two groups.

Case-Control Studies↗
PubMed2000

MEFV mutations in Turkish patients suffering from Familial Mediterranean Fever.

Familial Mediterranean fever (FMF) is a recessive inherited disorder affecting Sephardic Jews, Arabs, Armenians and Turks. The gene responsible for FMF was recently cloned and several disease-associated mutations have been described. We have evaluated seven MEFV mutations in 460 chromosomes of 230 unrelated patients with FMF living in Turkey, using PCR methods. The M694V allele accounted for 43.5% of the alleles studied and 19.1% of the patients were homozygous. The M680I, V726A and M694I mutations were responsible for 12.0%, 11.1% and 2.8% of the patients respectively. R761H, K695R and E148Q were rarely encountered. Two thirds of the disease alleles were attributed to three common mutations: M694V, M680V and V726A, but only 54% of the patients carried one or two of the three mutations. Adding the four rarer mutations increased these figures to 72% and 60%, respectively. Altogether, 79.6% of the patients bore at least one of the main mutations, and 84.3% carried at least one of the seven mutations studied. The 28 patients suffering also from amyloidosis carried at least one of five mutations, M694V being the most common. These results suggest that the origin of FMF in Turkey is heterogenous, all common mutations are associated with amyloidosis. Further, rapid and accurate molecular diagnosis of FMF is feasible in most cases.

Cytoskeletal Proteins↗
PubMed2000

Inherited protein-C deficiency, factor V G 1691 A and FV A 4070 G mutations in a child with internal cerebral venous thrombosis.

Common systemic disorders that cause cerebral venous thrombosis (CVT) in children include dehydration, trauma, infection and haematological diseases. No cause for CVT is identified in one quarter of all cases. We report a child with thalamic infarcts due to internal CVT who had congenital heterozygous protein-C deficiency, factor V G 1691 A and A 4070 G mutations.

Cerebral Veins↗
PubMed2000

MEFV mutations in multiplex families with familial Mediterranean fever: is a particular genotype necessary for amyloidosis?

Familial Mediterranean fever (FMF) is an autosomal recessive disease. It is characterized by recurrent febrile episodes in association with peritonitis, pleuritis, and arthritis. Progressive systemic amyloidosis is the most important complication of FMF that inevitably leads to chronic renal failure. Recently, the gene for FMF, MEFV, has been cloned and four missense mutations have been described: M694V, M680I, V726A, and M694I. Initial studies have suggested that the presence of the M694V mutation carries a significant risk for the development of amyloidosis. In this study, we present seven families, in which at least two individuals have been diagnosed with FMF and at least one with amyloidosis. Among 18 individuals, in whom molecular testing was performed for the four aforementioned mutations, ten had amyloidosis. None of these ten individuals was found to be homozygous for the M694V mutation. In three families, there were two sibs with amyloidosis. None of the sib-pairs with amyloidosis was found to have the same genotype. There were two or more sibs with the same genotype in four families. Only one sib from each family developed amyloidosis in these families. These results provide evidence that FMF patients without the M694V mutation are also at risk for the development of amyloidosis. Particular mutations themselves do not appear to be sufficient to explain the occurrence of amyloidosis in all cases with FMF.

Adolescent↗
PubMed2000

Patterns of male-specific inter-population divergence in Europe, West Asia and North Africa.

We typed 1801 males from 55 locations for the Y-specific binary markers YAP, DYZ3, SRY10831 and the (CA)n microsatellites YCAII and DYS413. Phylogenetic relationships of chromosomes with the same binary haplotype were condensed in seven large one-step networks, which accounted for 95% of all chromosomes. Their coalescence ages were estimated based on microsatellite diversity. The three largest and oldest networks undergo sharp frequency changes in three areas. The more recent network 3.1A clearly discriminates between Western and Eastern European populations. Pairwise Fst showed an overall increment with increasing geographic distance but with a slope greatly reduced when compared to previous reports. By sectioning the entire data set according to geographic and linguistic criteria, we found higher Fst-on-distance slopes within Europe than in West Asia or across the two continents.

Africa, Northern↗
PubMed2000

Clinical, laboratory and molecular characteristics of children with Familial Mediterranean Fever-associated vasculitis.

Familial Mediterranean Fever (FMF) is an autosomal recessive disease characterized by recurrent self-limited attacks of fever accompanied by peritonitis, pleuritis and arthritis. Approximately 5% of individuals with FMF have been reported to have Henoch-Schönlein purpura (HSP) and about 1% have polyarteritis nodosa (PAN). Protracted febrile myalgia is another vasculitis-associated clinical entity among patients with FMF. Recently, the gene responsible for FMF, MEFV, has been cloned and four missense mutations (M680I, M694V, V726A and M694I) have been described. In this report, we present clinical and laboratory findings and mutation results of 23 children with FMF-associated vasculitis. HSP, PAN and protracted febrile attacks have been diagnosed in 11, 2 and 10 children, respectively. Mutation analysis shows that 3 children are homozygotes for the M694V mutation and 11 are compound heterozygotes for 2 of the studied mutations. M694V/V726A mutations were identified in 8, M694V/M694I in 2 and M680I/M694V in 1 of these children. In six children only one mutation was found and in three none of the studied mutations were identified. This study confirms that most children with FMF-associated vasculitis have identifiable mutations in the MEFV gene. Environmental and/or other genetic factors are possibly involved in the pathogenesis of vasculitis in FMF; elucidation of these mechanisms will help to understand pathogenesis of childhood vasculitides.

Adolescent↗
PubMed2000

Familial Mediterranean fever and systemic amyloidosis in untreated Turkish patients.

We compared the frequencies of seven MEFV mutations (M694V, M680I, V726A, M694I, K695R, R761H, E148Q) and the clinical findings in 20 Turkish FMF patients who had not developed amyloidosis by the age of 40 years in the absence of colchicine therapy, with those in 27 Turkish amyloidosis patients. No mutation frequency, including that of M694V, was different between the two groups. Family history of amyloidosis and parental consanguinity were noted to be higher in the amyloidosis group. The seven mutations do not appear to be sufficient to explain the development of amyloidosis in Turkish FMF patients. Other genetic factors may be important for this association.

Adult↗
PubMed2000

Genotype-phenotype correlation in a large group of Turkish patients with familial mediterranean fever: evidence for mutation-independent amyloidosis.

OBJECTIVES: Differences in clinical manifestations of familial Mediterranean fever (FMF) between different ethnic groups have been documented. The FMF gene was recently cloned and four missense mutations (Met694Val, Met680Ile, Val726Ala, and Met694Ile) that account for a large percentage of the patients were identified. The results of initial mutation studies have led to the hypothesis that phenotypic variation of the disease may be attributable to the existence of some of these mutations. The purpose of this study was to evaluate whether this phenotypic variation is associated with the existence of particular mutations in Turkish FMF patients living in Turkey. METHODS: Four missense mutations and genotype-phenotype correlation were investigated in 167 Turkish FMF patients. The patients were grouped according to the presence of the Met694Val and the Met680Ile mutations, and 12 clinical parameters were compared between the groups. RESULTS: The presence of the Met694Val mutation was not found to be associated with a severe form of the disease or the development of amyloidosis. Arthritis frequency was found to be lower in the patients with homozygous Met680Ile mutation. CONCLUSIONS: None of the four missense mutations is associated with a severe disease or the development of amyloidosis in Turkish FMF patients living in Turkey. The influence of unknown environmental factors and/or the presence of other genetic changes are necessary to explain the phenotypic variation of the disease and the development of amyloidosis.

Adolescent↗
PubMed2000

Prothrombin gene 20210 G-->A and Factor V Arg 506 to Gln mutation in a patient with Buerger's disease--a case report.

Thromboangiitis obliterans, or Buerger's disease, is a segmental occlusive inflammatory disorder of the arteries and veins most commonly affecting the lower extremities of young male cigarette smokers. The etiopathogenesis of the thromboangiitis obliterans is still obscure. The authors have identified heterozygosity for the recently described prothrombin gene 20210 G-->A variation and Factor V Arg 506 to Gln (Factor V Leiden) mutation in a patient with Buerger's disease. Both mutations confer a high risk of thrombosis. This coincidental observation may serve as further evidence that a thrombotic mechanism is involved in Buerger's disease.

Adult↗
PubMed1999

Plasma endothelin-1 levels in patients with left-to-right shunt with or without pulmonary hypertension.

The aim of this study was to evaluate the role of endothelin-1 (ET-1) in pathophysiology of pulmonary hypertension (PH) secondary to congenital heart disease with left-to-right shunt. Twenty-three children (12 male, 11 female) aged 0.58-13 years were enrolled the study. Blood samples were drawn from superior vena cava, right atrium, right ventricle, pulmonary artery and pulmonary wedge or pulmonary vein during cardiac catheterization. Plasma ET-1 levels were assayed by ELISA. Patients were divided into two groups according to the presence or absence of PH. Plasma ET-1 levels of the study group were compared to the peripheral venous and arterial ET-1 levels of 11 healthy infants and children (aged 0.75-13 years). Plasma ET-1 levels in patients with left-to-right shunt were found significantly higher than those of controls. However, plasma ET-1 levels were similar between the two groups of the patients. Pulmonary venous ET-1 levels were higher than the levels of superior vena cava, this suggested an increased production of ET-1 in pulmonary vascular bed in patients with PH. No correlations were found between plasma ET-1 levels and pulmonary arterial pressure, pulmonary vascular resistance and pulmonary blood flow in the patients. Plasma ET-1 levels of the patients with left-to-right shunt were increased independently from pulmonary arterial pressure and pulmonary vascular resistance. This increase was related to the production of ET-1 in pulmonary vascular bed in patients with PH. ET-1 could not be found to be directly related to the development of PH in the patients with left-to-right shunt.

Adolescent↗