Gunay Balta

Evidence for the Existence of the PAF Acetylhydrolase Mutation (Val279Phe) in Non-Japanese Populations: A Preliminary Study in Turkey, Azerbaijan, and Kyrgyzstan

Deficiency of plasma platelet-activating factor (PAF) acetylhydrolase resulting from a missense mutation (Val279Phe) in exon 9 of the gene has been described exclusively in the Japanese population with a very high frequency. This study describes the distribution of the mutation in Turkey and two other Turkic nations, Kyrgyzstan in central Asia and Azerbaijan bordering the Caspian Sea. Among 358 unrelated healthy subjects studied from Turkish population, only 3 had the mutation in heterozygous state (0.84%). Family studies also revealed the presence of homozygous individuals in close relatives of one of these subjects. Among 143 healthy subjects studied from Kyrgyzstan, 12 were heterozygous for the mutation (8.4%). No mutation was detected among 100 healthy individuals studied from Azerbaijan. However, it was suggested that the number of subjects was not enough to draw any conclusion about the prevalence of the mutation in the populations studied. Contrary to the previous notions, identification of the mutation in Turkey and Kyrgyzstan shows the existence of the mutation in non-Japanese populations as well.

Clinical and molecular aspects of Turkish familial hemophagocytic lymphohistiocytosis patients with perforin mutations

The aim of this study was to elucidate the pathologic sequence changes and associated clinical phenotypes in 9 new patients showing homozygosity for perforin gene among a total of 37 (24%) Turkish FHL families studied by linkage analysis. These 9 unrelated patients (5M/4F) were coming from consanguineous families and their presentation ages of systemic symptoms were ranged from birth to 15 years. Direct sequencing of coding exons of the perforin gene led to the identification of five different homozygous alterations. The nonsense W374X mutation was identified in three patients while four different missense mutations namely G149S, V50M, A91V and novel A523D were detected in the rest six patients.

Central Nervous System Involvement in Turkish Children With Primary Hemophagocytic Lymphohistiocytosis

This report mainly presents the clinical and laboratory findings in a group of 15 primary hemophagocytic lymphohistiocytosis patients with central nervous system involvement (group 1) and compares some of the findings with those of 13 hemophagocytic lymphohistiocytosis patients without central nervous system involvement (group 2). Statistical analysis showed that age and sodium level at diagnosis were significantly higher while alanine aminotransferase and bilirubin levels were significantly lower in group 1 than group 2 (P < .05). There were no statistically significant differences between the 2 groups in the other clinical, laboratory, and overall survival parameters. Three patients in group 1 initially had central nervous system involvement in the absence of systemic findings, which led to the initial misdiagnosis of these patients as central nervous system disorders other than hemophagocytic lymphohistiocytosis.

Significance of factor V, prothrombin, MTHFR, and PAI-1 genotypes in childhood cerebral thrombosis.

The aim of this study was to evaluate the significance of factor V (FV) G1691A, prothrombin G20210A, methylenetetrahydrofolate reductase (MTHFR) C677T, and plasminogen activator inhibitor-1 (PAI-1) 4G/5G genotypes in development of childhood cerebral thrombosis (CT). A total of 113 Turkish children with CT were studied and compared with the control group. The carrier frequency of the factor V G1691A mutation was found to be significantly higher in the patient group (17.7%) than controls (7.4%). The presence of this genotype was associated with a 2.7-fold increased risk of developing CT (95% confidence interval [CI], 1.0—7.0). The prevalence of prothrombin G20210A mutation in 110 patients (4.5%) was insignificantly higher than controls (2.3%) (odds ratio, 2.0; 95% CI, 0.4—10.7). A statistically significant increase in the frequency of homozygous MTHFR C677T genotype was observed in 62 patients (11.3%) compared to controls (4.3%), and this genotype was associated with 2.8-fold increased CT risk (95% CI, 1.0—8.0). The incidence of PAI-1 4G/4G genotype in 65 patients (21.5%) was slightly lower than that of controls (26.0%), but the differences did not reach statistical significance (odds ratio, 0.8; 95% CI, 0.4—1.5). The results of this study suggested that factor V G1691A and MTHFR C677T genotypes may be associated with an increased risk of developing CT in Turkish children.

Analysis of some clinical and laboratory aspects of adolescent patients with thrombosis.

A total of 360 pediatric patients aged 1 month to 18 years were diagnosed as having thrombosis between January 1998 and April 2003. Of these patients, those aged 11–18 years (n = 131) were regarded as adolescents and the rest as children. The proportion of adolescents in the whole group excluding the neonates was 36%. The peak age of diagnosis in adolescents was 11–14 years, comprising 58% of all thrombotic events in adolescents. In 73% of the adolescents, there was at least one risk factor. The four most common underlying disorders were infection, malignancy, connective tissue and cardiac disorders, in decreasing order of frequency. In children, on the other hand, infection was followed by congenital heart disease, malignancy and liver disease. Three common types of thrombosis in adolescents were deep venous thrombosis, cerebro-vascular events and portal venous thrombosis, while cerebro-vascular events were the most common in children. The frequency of factor V G1691A mutation in the adolescents (22.1%) was significantly higher than that found in a group of healthy controls (7.4%) and this mutation was associated with a 3.6-fold increase in the risk of developing thrombosis (95% confidence interval, 1.4–9.0). The carrier frequency of prothrombin G20210A mutation (3.1%) in adolescents did not differ significantly from that of the healthy population (2.3%) and no association was observed between this mutation and a risk of developing thrombosis in this group (odds ratio, 1.3; 95% confidence interval, 0.2–7.5). The rate of recurrent thrombosis was 6%.

Hemophagocytic syndrome in a child with severe Crohn's disease and familial Mediterranean fever

Hemophagocytic lymphohistiocytosis (HLH) is a rare, potentially fatal, severe condition of hyperinflammation caused by the uncontrolled proliferation of activated lymphocytes and histiocytes secreting high amounts of inflammatory cytokines. Here we report a fatal hemophagocytic syndrome in a 11-year-old boy with a diagnosis of both Crohns disease receiving immunosuppressive therapy and familial Mediterranean fever. It is important to evaluate the patients with inflammatory bowel disease receiving immunosuppressive therapy presenting with unexplained fever, cytopenia, progression of organomegaly and biochemical changes for the investigation of HLH for diagnosis and treatment.

Assessment of clinical and laboratory presentations of familial hemophagocytic lymphohistiocytosis patients with homozygous W374X mutation

Homozygous W374X mutation was identified in unrelated 13 patients (6M/7F) from consanguineous families, 62% of which had history of deceased sibling. Haplotype analysis provided evidence for the probable existence of a founder effect. Age at disease onset ranged from 1 day to 5.5 months (median 2 months). Hepatic dysfunction was observed in 69%, ascite 62%, hypertriglyceridemia 77%, each hyperferritinemia and hypofibrinogenemia 85%, CNS involvement 46% of patients while birth weights were in normal range. Those with very high ferritin (>20,000ng/ml) had extremely low fibrinogen levels. Two-thirds of patients receiving HLH protocol died within 20 days of therapy.

Fanconi anemia A due to a novel frameshift mutation in hotspot motifs: lack of FANCA protein.

Homozygosity for a frameshift mutation at codon 1213 of FANCA gene was identified in a Turkish patient. Immunoprecipitation‐western blot analysis showed the complete absence of the FANCA protein band. This novel mutation, a deletion of T at position 3639 in exon 37 (3639delT), is responsible for the disease and causes premature termination of translation 32 aa downstream. The deletion is (i) the T residue of 2 overlapping TGAGGC and CCTG hot spot motifs, (ii) flanked by several direct repeats, (iii) surrounded by the highly GC rich region that have frequently been identified at the site of human DNA deletions. The patient is the third living child of a first degree cousin marriage. The major abnormalities of the patient at the age of 6 months were growth retardation, microcephaly, hypoplastic right thumb, distal displacements of both thumbs and pelvic displacement of left kidney. Hematological presentation of the disease started before the age of 4 years. Hum Mutat 15:578, 2000.

Clinical and laboratory evaluation of Turkish children with thrombosis for homozygous factor V G1691A mutation

Factor V (FV) G1691A mutation, in a heterozygous state, is one of the most common inherited risk factors for development of thrombosis. However, the clinical manifestations of homozygosity for the FV G1691A mutation in children is largely unknown because of the limited number of studies reported. The purpose of this study was to evaluate the clinical manifestations and laboratory findings of children with thrombosis who were homozygous for this mutation. Ten patients (four male/six female; mean age, 4.5 years; age range, 1–13 years) who were found to be homozygous for the FV G1691A mutation among 360 consecutive children with thrombosis (2.8%) were the subjects of this study. Six of the 10 patients had venous thrombosis, two had purpura fulminans, one had diffuse skin ecchymosis and one had arterial thrombosis. No history of thrombosis was present in their family members. Seven of the 10 children were under the age of 5 years. One or more additional risk factors (infection, protein S and protein C deficiencies, elevated factor VIII, etc.) were also present in nine of these patients. None of these patients had prothrombin G20210A mutation but one patient had risk-associated plasminogen activator inhibitor-1 gene 4G/4G genotype. These findings suggest that, in the presence of other underlying risk factors, homozygosity for FV G1691A mutation may lead to development of thrombosis at a very young age.

Significance of fetal hemoglobin values in detection of heterozygotes in fanconi anemia: reevaluation of fetal hemoglobin values by a sensitive method.

Fanconi anemia (FA) is a genetically very heterogeneous disease making routine detection of carriers quite difficult by molecular analysis. Finding alternative method has vital importance especially in populations where prevalence of the disease is quite high because of consanguineous marriages. The aim of this study was to find a considerably reliable parameter to detect FA carriers by methods other than molecular analysis. The subjects of this study were 66 parents of children with FA and 40 age and sex compatible individuals from the normal healthy population. An index family with a known mutation was also included as an evidence for verification of the results. The mean fetal hemoglobin (HbF) values (0.81%±0.72%) of FA heterozygotes studied by high-performance liquid chromatography was significantly higher than that (0.37%±0.32%) of the control group (P<0.001). Additionally, there was a positive correlation between the HbF value of the children (mean: 4.50±1.59) and the parents (mean: 0.81±0.72) (r: 0.698, P=0.01). No significant difference was detected between the hemoglobin, hematocrit, red blood cell count, mean corpuscular volume, red cell distribution width, white blood cell count, absolute neutrophil count, and platelet counts of the study and control groups. The results of this study suggest that the HbF values may be used as a marker to predict carriers in the family members of a child with FA when definitive diagnosis by molecular analysis is not possible.