Ece Akar

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. Hum Mutat 15:118–119, 2000.

Common Mutations at the Homocysteine Metabolism Pathway and Pediatric Stroke

Heterozygosity and/or homozygosity for mutations at the genes of the enzymes involved in homocysteine metabolism may confer an increased risk for thrombosis by causing hyperhomocysteinemia. Although the mutations related to homocysteine metabolism possibly increase the risk of stroke, the data are conflicting and there are very few reports linking these defects to acute stroke in children. We aimed to study the role of these mutations in Turkish children with ischemic stroke. Forty-six patients having cerebral infarct were clinically diagnosed, and the infarction verified with magnetic resonance imaging of the brain was included in the study. All patients were below the age of 18 (10 months to 18 years). Sixty-eight controls, consecutively selected among healthy unrelated subjects from the same geographic area of Turkey without personal and family history of thrombosis, stroke or Behests disease, were included. Genotyping for the common mutations was carried out by the methods described previously. There was no difference between the pediatric stroke patients and controls for the distribution of methylene tetrahydrofolate reductase (MTHFR) 677 C-T, MTHFR 1298 A-C, methylene tetrahydrofolate dehydrogenase (MTHFD) 1958 G-A and methionine synthase reductase (MTRR) 66 A-G alleles. There was no risk for double gene alterations (MTHFR 677 C-T vs. 1298 A-C) after individuals with FV 1691 A mutation is excluded. Twelve of the 46 patients were found to carry FV 1691 A mutation (26.0%), one being homozygote. The cerebral infarct risk for FV 1691 A was found to be 6.4 (CI 95% 1.7-23.0). Eight of the 46 patients were found to carry PT 20210 A mutation (16.6%). Two of the FV 1691 A heterozygous patients carried PT 20210 A mutation at the same time (4.2%). As a conclusion, we can say that FV 1691 A and PT 20210 A mutations are important and must be included to the routine analysis of pediatric stroke patients.

Effect Of Metylenetetrahydrofolate 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.

Effect of plasminogen activator inhibitor-1 4G/5G polymorphism in Turkish deep vein thrombotic patients with and without FV1691 G-A.

A decreased fibrinolytic activity due to increased levels of plasminogen activator inhibitor-1 has been shown in deep vein thrombosis patients. Elevated plasma plasminogen activator inhibitor-1 levels are associated with the 4G allele of a 4G/5G polymorphism located in the promoter region of the plasminogen activator inhibitor-1 gene. Because there is no existing data in the Turkish population, we aimed to study these mutations in patients with deep vein thrombosis (n = 136) and normal controls (n = 113), consecutively selected among unrelated healthy subjects without personal and familial history of atherothrombosis from Ankara, Turkey. DNA was extracted by conventional methods, and polymerase chain reaction of the plasminogen activator inhibitor-1 4G/5G polymorphism was performed according to a previously described method. Genotype distributions of FV 1691G-A and plasminogen activator inhibitor-1 4G/5G are as follows: plasminogen activator inhibitor-1 4G (patients) 0.562, plasminogen activator inhibitor-1 4G (controls) 0.50 (p = 0.6); FV1691A (patients) 0.147, FV1691A (controls) 0.035 (p = 0.005). Our data indicated that plasminogen activator inhibitor-1 4G/5G does not have an effect on the thrombotic risk. Carrying the 4G allele either in heterozygous or homozygous state increases the risk in the presence of FV1691A (odds ratio: 9.8 and 6.9, confidence interval 95% 2.9-32.7 and 1.3-35.8). FV1691A is an independent risk factor for thrombosis (odds ratio: 5.5, confidence interval: 95% 2.5-12.1). We concluded that coexistence of FV1691A and plasminogen activator inhibitor-1 4G allele leads to an increased risk for thrombosis leading a further evidence to another prothrombotic factor that may be necessary for the development of a manifest thrombotic event.

The Role of Prothrombotic Mutations in Patients with Buerger's Disease

Thromboangiitis obliterans (TAO), or Buergers disease, is a segmental occlusive inflammatory disorder of the arteries and veins, and etiopathogenesis is still obscure. In the present study we investigated the prevalence of prothrombin 20210 G-->A, factor V 1691 G-->A (Factor V Leiden), and factor V 4070 A-->G (His 1299 Arg) mutations, found to be associated with increased risk for vascular thrombosis, in 36 patients with TAO. We performed a case-control study of these mutations. The odds ratio for prothrombin 20210 A allele compared with G allele was 7.98 (95% confidence intervals 2. 45-25.93). Only this prothrombotic genetic factor was associated with the risk of TAO (p=0.032). In conclusion, carrying the prothrombin 20210 G-->A may be an important prothrombotic risk factor of TAO. This genetic predisposition must be screened in these patients routinely, and clinical importance must be supported by further investigations.

Search for genetic factors favoring thrombosis in Turkish population.

Common mutations in three genes (MTHFR 677 C-T; MS 2756 A-G; CBS Exon 8,844 ins 68) in homocysteine metabolism have been shown to cause increased plasma homocysteine levels thus causing a predisposition to thrombosis. FV 1691 G-A mutation, which is very common in the Turkish population, was also studied. As there is no existing data in the Turkish population, we aimed to study these mutations in patients with thrombosis and normal controls. The case-control study included 52 patients with the diagnosis of deep vein thrombosis (DVT) and 106 controls, consecutively selected among subjects without personal and family history of atherothrombosis. Patients with DVT were selected if Doppler ultrasonography was positive. The comparison of FV 1691 G-A mutation revealed statistically significant difference in control and DVT group. Risk assessment of double prothrombotic gene alterations indicated only FV 1691 G-A mutation as an independent risk factor for thrombosis, but our data suggested that MTHFR 677 has little effect on its own but may have synergy with FV 1691 G-A. Other possible risk genotypes at the homocysteine pathway did not have a significant effect on thrombosis. Furthermore, being heterozygote at two different loci or homozygosity at least in one locus also did not reveal a significant difference between these two groups in our population.

Serum amyloid A1 and tumor necrosis factor-alpha alleles in Turkish Familial Mediterranean Fever patients with and without amyloidosis

The major complication of familial Mediterranean fever (FMF) is AA amyloidosis. The influence of FMF gene (MEFV) mutations and or unknown environmental factors and other genetic modifiers are likely to affect the pheno-typic variations of the disease and the development of amyloidosis. Serum amyloid A is a serum precursor of AA amyloid that is induced by inflammatoy cytokines including TNF-a. Our analysis of SAAI.1 frequency in Turkish FMF-amyloidosis patients, revealed a higher frequency compared to non FMF-amyloidosis patients but the difference was not significant. On the other hand, the distribution of SAAI.1 homozygosity among FMF-amyloidosis patients was 55.5 % compared to FMF-non-amyloidosis patients (30.8 %) which was statistically significant revealing a 2.5 fold risk for the occurrence of amyloidosis. There was no significant difference between the controls and FMF patients with and without amyloidosis for the TNF-α-308 G-A allele. It is worth noting that all TNF-α -308 G-A carriers (n=6) in FMF-amyloidosis group have SAAI.1 homozygosity compared to 2/11 in FMF-non-amyloidosis group. Further evaluation of these polymorphisms may have importance and need further study.

Endothelial nitric oxide synthase intron 4, 27 bp repeat polymorphism in Turkish patients with deep vein thrombosis and cerebrovascular accidents.

of the Turkish population. Ninety-five apparently healthy unrelated individuals without any familial

Plasminogen Activator Inhibitor-1 4G/5G Polymorphism in Turkish Children With Cerebral Infarct and Effect on Factor V 1691 A Mutation

The thrombotic risk of carrying plasminogen activator inhibitor-1-675 4G allele was found to be controversial in previous studies. The aim of this study was to evaluate the possible effect of plasminogen activator inhibitor-1 4G/5G polymorphism in the pathogenesis of childhood stroke. The case-control study included 43 patients with cerebral infarct who were below the age of 18 years (range, 10 months to 18 years) and 113 healthy unrelated individuals without family histories of thrombosis. Plasminogen activator inhibitor-1 4G/5G polymorphism was analyzed according to a previously described method. There was no statistically significant difference in patient and control groups for the distribution of plasminogen activator inhibitor-1 4G/5G polymorphism (P = .75) (allele frequency 4G controls: 0.50; patients: 0.53). However, there was a significant difference for the factor V (FV) 1691 A mutation for both groups (P = .0007). (J Child Neurol 2001;16:294-295).

Isolated recurrent pericarditis in a patient with familial Mediterranean fever.

Familial Mediterranean fever (FMF) should be kept in mind in the differential diagnosis of recurrent pericarditis and mutation analysis should be considered, especially in patients of Mediterranean origin.