Spectrum, and clinical and functional implications of UNC13D mutations in familial haemophagocytic lymphohistiocytosis.

OBJECTIVE: Familial haemophagocytic lymphohistiocytosis (FHL) is a fatal disorder of immune dysregulation with defective cytotoxic lymphocyte function. Disease-causing mutations have been identified in the genes encoding perforin (PRF1), syntaxin-11 (STX11), and Munc13-4 (UNC13D). We screened for UNC13D mutations and studied clinical and functional implications of such mutations in a well defined patient cohort. METHODS: Sequencing of UNC13D was performed in 38 FHL patients from 34 FHL families in which PRF1 and STX11 mutations had been excluded. RESULTS: We identified six different mutations affecting altogether 9/38 individuals (24%) in 6/34 (18%) unrelated PRF1/STX11-negative families. Four novel mutations were revealed; two homozygous nonsense mutations (R83X and W382X), one splice mutation (exon 28), and one missense mutation (R928P). In addition, two known mutations were identified (R214X and a deletion resulting in a frame-shift starting at codon 782). There was considerable variation in the age at diagnosis, ranging from time of birth to 14 years (median 69 days). Three of nine patients (33%) developed central nervous system (CNS) symptoms. Natural killer (NK) cell activity was impaired in all four patients studied. Defective cytotoxic lymphocyte degranulation was evident in the two patients investigated, more pronounced in the patient with onset during infancy than in the patient with adolescent onset. CONCLUSIONS: Biallelic UNC13D mutations were found in 18% of the PRF1/STX11-negative FHL families. Impairment of NK cell degranulation was less pronounced in a patient with adolescent onset. FHL should be considered not only in infants but also in adolescents, and possibly young adults, presenting with fever, splenomegaly, cytopenia, hyperferritinaemia, and/or CNS symptoms.

Sequencing of the factor 8(F8) coding regions in 10 Turkish hemophilia A patients reveals three novel pathological mutations, and one rediagnosis of von Willebrand's disease type 2N.

The most common cause for severe cases of hemophilia A is the homologous recombination involving intron 22 and related sequences outside the F8 gene. F8 coding regions of the gene including the exon/intron junctions were sequenced in 10 Turkish hemophilia A patients all of whom have been typed negative for intron 22 inversion and who did not have a detectable change by DGGE analysis. Pathological changes including two novel deletions (c. 205del CT and c. 3699del ACAT), one novel missense mutation (9546A) and two recurrent missense mutations were observed in five patients. The c. 2110C > T is another novel pathological change affecting exonic splicing enhancer site in two patients. One of the remaining three patients had a recurrent vWD type 2N mutation in the F8 binding site of the vWF (C788R). The S1269S polymorphism (c. 3864A > C) detected phenotype. Conclusively, sequencing of the promoter and the coding regions of 10 hemophilia A patients contributes four novel pathological mutations to the F8 mutations list and reveals a rediagnosis of hemophilia A but is still not sufficient to confirm hemophilia A phenotype in two patients.

High frequency of thrombophilic disorders in women with recurrent fetal miscarriage.

OBJECTIVES: Our purpose was to examine whether genetic thrombophilias are etiological factors for recurrent fetal miscarriage or not. STUDY DESIGN: We compared the rate of thrombophilic anomalies in women with unexplained recurrent fetal miscarriages to the rate of age-matched women with successful pregnancies as a case-control study. RESULTS: A total of 101 consecutive patients with 102 age-matched controls were included in the study. The rate of Factor V (FV) Leiden mutation, Factor (F) II mutation, protein S, protein C, antithrombin III deficiencies and overall thrombophilia in patients with recurrent fetal loss was significantly higher than the frequencies in control patients. CONCLUSION: Women with recurrent fetal miscarriages have an increased incidence of thrombophilia. Genetic thrombophilias may be one of the major etiological factors for recurrent abortion and fetal demise.

Diffusion-weighted cranial MR imaging findings in a patient with hemophagocytic syndrome.

Hemophagocytic lymphohistiocytosis (HLH) is a rare disorder of the immune system that is associated with frequent involvement of the central nervous system (CNS). The MR imaging and CT findings of the CNS infiltration have been reported in the past; however, the diffusion-weighted imaging (DWI) findings have not been previously described. We present MR imaging findings in a case of secondary HLH with CNS involvement, with an emphasis on the DWI findings.

Spectrum and clinical implications of syntaxin 11 gene mutations in familial haemophagocytic lymphohistiocytosis: association with disease-free remissions and haematopoietic malignancies.

OBJECTIVE: To determine the frequency and spectrum of mutations in the gene encoding syntaxin 11 (STX11) in familial haemophagocytic lymphohistiocytosis (FHL), a rare autosomal recessive disorder of immune dysregulation characterised by a defect in natural killer cell function. METHODS: Mutational analysis of STX11 by direct sequencing was done in 28 FHL families that did not harbour perforin mutations, previously identified in some FHL patients. A detailed investigation of clinical features of these patients was also undertaken. RESULTS: Two different STX11 mutations were identified, one nonsense mutation and one deletion, affecting six of 34 children in four of 28 unrelated PRF1 negative families. Both mutations have been reported before. Three patients experienced long periods (> or = 1 year) in remission without specific treatment, which is very uncommon in this disease. Despite the milder phenotype, some children with STX11 mutations developed severe psychomotor retardation. Two of the six patients harbouring STX11 gene defects developed myelodysplastic syndrome (MDS) or acute myelogenous leukaemia (AML). CONCLUSIONS: STX11 gene mutations were found in 14% of the PRF1 negative FHL families included in the present cohort. These results suggest that STX11 gene mutations may be associated with secondary malignancies (MDS/AML), and that there is segregation of specific clinical features in FHL patients with an underlying genotype.

Severe hemolytic anemia associated with Hb Volga [beta27(B9)Ala-->Asp]: GCC-->GAC at codon 27 in a Turkish family.

A boy presented at age 4 years with severe congenital hemolytic anemia characterized by highly elevated reticulocyte count (30-50%) and prominent basophilic stippling. Hb had been 4 g/dL at age 7 months. The patient was on a monthly transfusion regimen up to the age of 7 years, when he underwent splenectomy. After removal of the spleen, his Hb stabilized at 11 g/dL. No abnormal pattern was detected in hemoglobin electrophoresis at pH 9 and 6. In-vitro globin synthesis revealed the presence of an abnormal beta-chain in front of the gamma-chain. The beta(A)/beta(X) ratio was 0.77 at 30 min and 0.74 at 2 hr of incubation. Molecular analysis revealed that the patient had GCC-->GAC alteration at codon 27 (beta27(B9)Ala-->Asp) causing the abnormal hemoglobin Volga. The beta-cDNA derived from the beta-Hb Volga allele could be differentiated from HbA beta-cDNA on silver-stained gel. No imbalance in the mRNA of beta(A)/beta(Hb Volga) ratio was observed.

The predictability of factor V Leiden (FV:Q(506)) gene mutation via clotting-based diagnosis of activated protein C resistance.

After the discovery of activated protein C resistance (APCR) due to factor V Leiden mutation and the causal relationship of the phenomenon with clinical thromboembolism, a wide variety of functional clotting-based assays were developed for testing of APCR in relation to the specific DNA-based analysis of FV:Q(506) Leiden. The aim of this study is to assess a clotting-based APCR assay using procoagulant crotalidae snake venom with respect to the sensitivity, specificity, and predictability for the presence of the factor V Leiden mutation. APCR testing and factor V DNA analyses have been performed concurrently on 319 patient specimens. APCR values of the patients with homozygous factor V Leiden mutation (70.4+/-13.5 s) were significantly lower (p<0.001) in comparison to the subjects with the heterozygous mutation (87.6+/-13.4 s). The assay is highly sensitive (98.7%) and specific (91.9%) for the screening of factor V Leiden mutation. The sensitivity and specificity of the APCR testing reached to 100% below the cut-off value of 120 s among the patients with homozygous factor V Leiden mutation. Therefore, this method could help the desired effective optimal screening strategy for the laboratory search of hereditary thrombophilia focusing on the diagnosis of APCR due to FV:Q(506).

The effect of hydroxyurea on the coagulation system in sickle cell anemia and beta-thalassemia intermedia patients: a preliminary study.

Hydroxyurea (HU) has been shown to reduce the frequency of vaso-occlusive manifestations in both adults and children with sickle cell disease (SCD), and the induction of hemoglobin F (HbF) is thought to be the underlying mechanism responsible for clinical improvement in some patients. However, there exists no good correlation between the amount of HbF increase and clinical response. Recent studies suggest that increased activity of the coagulation system may be important in the pathogenesis of vascular occlusion in sickle cell disease. To analyze the effect of HU on the coagulation system in children, the authors studied the levels of some coagulation factors and natural inhibitors. Eleven children who had been treated with HU because of SCD (5 patients), sickle-beta-thalassemia (3 patients), and beta-thalassemia intermedia (3 patients) were enrolled in the study. Levels of the coagulation factors II, V, VII, VIII, IX, X, XI, and XII, and of protein C and protein S, prothrombin times, activated partial thromboplastine times, thrombin times, and reptilase times were measured before the treatment and at the 5th or 6th months of HU therapy when the patients were in a steady-state condition. There was a decrease in all of the coagulation factors except for FIX and FXII and in inhibitors such as protein C and protein S. However, statistically significant decreases were observed only in factor VIII and protein C levels. The rates of decrease were 54.8 and 12.5% (p = .015 and p = .018) in FVIII and protein C, respectively. This result shows that HC has significant effects on the coagulation and natural inhibitory systems.

Primary hemophagocytic lymphohistiocytosis in Turkish children.

Nineteen children with hemophagocytic lymphohistiocytosis (HLH) were studied in the Department of Pediatric Hematology, Hacettepe University. Patients were divided into two groups. Group 1: Thirteen patients were classified as having a genetic etiology (7 familial, 6 presumed familial) on the basis of an affected sibling and consanguinity. There was a history of consanguineous marriage in 13 of the families. Seven of them had a history of a sibling with HLH. Group 2: Six patients were diagnosed with sporadic HLH. The age at presentation for familial patients was 0.7-84 months (mean 21.9 +/- 24.9 months), and for sporadic cases it was 2.5-48 months (mean 22.7 +/- 19.8 months). The clinical and laboratory data of these two groups were similar at diagnosis. Thirteen cases were diagnosed premortem by bone marrow aspiration. Splenic biopsy was performed in 2 patients. Four patients were diagnosed by postmortem examination. Elevated LDH levels were found in all patients tested. No significant differences for clinical and laboratory data were found between the two groups.

Benefit of high-dose methylprednisolone in comparison with conventional-dose prednisolone during remission induction therapy in childhood acute lymphoblastic leukemia for long-term follow-up.

Eight-year event-free survival (EFS) was evaluated in 205 patients with acute lymphoblastic leukemia (ALL), to consider the efficacy of high-dose methylprednisolone (HDMP) given during remission induction chemotherapy between 1 and 29 days. The St Jude Total XI Study protocol was used after some minor modifications in this trial. Patients were randomized into two groups. Group A (n = 108) received conventional dose (60 mg/m(2)/day orally) prednisolone and group B (n = 97) received HDMP (Prednol-L, 900-600 mg/m(2) orally) during remission induction chemotherapy. Complete remission was obtained in 95% of the 205 patients who were followed-up for 11 years; median follow-up was 72 months (range 60-129) and 8-year EFS rate was 60% overall (53% in group A, 66% in group B). The EFS rate of group B was significantly higher than of group A (P = 0.05). The 8-year EFS rate of groups A and B in the high-risk groups was 39% vs 63% (P = 0.002). When we compared 8-year EFS rate in groups A and B in the high-risk subgroup for both ages together /=10 years, it was 44% vs 74%, respectively. Among patients in the high-risk subgroup with a WBC count >/=50 x 10(9)/l, the 8-year EFS was 38% in group A vs58% in group B. During the 11-year follow-up period, a total of 64 relapses occurred in 205 patients. In group A relapses were higher (39%) than in group B (23%) (P = 0.05). These results suggest that HDMP during remission-induction chemotherapy improves the EFS rate significantly for high-risk patients in terms of the chances of cure.

Thrombosis in children with cardiac pathology: frequency of factor V Leiden and prothrombin G20210A mutations.

This study analyzed 28 thrombotic children with various cardiac disorders. They comprise 17% of a total of 168 patients with thrombosis from a single center. Among the 28 patients, 21 had congenital heart disease and 7 were diagnosed with cardiomyopathy. The patients with thrombosis were evaluated for congenital and acquired thrombotic risk factors. In addition to cardiac disorders, two, three, or more risk factors were present in 61% of the children with thrombosis. Two common mutations, namely factor V Leiden and prothrombin G20210A mutations, were found in 6 patients (22%). Nine patients (32%) died of infection, congenital heart disease, cardiomyopathy, thrombosis, operation, or a combination of these; two patients required surgical intervention. Following cardiac angiography, due to necrosis, amputation of the right index finger and right lower extremity was performed on 1 patient. The second patient's index fingers had to be amputated and resection of the bowel was performed following the operation on coarctation of the aorta. This study indicates that congenital heart disease and cardiomyopathy are two common cardiac disorders that may lead to the development of thrombosis. The majority of thrombosis develops within the heart and/or its great vessels. The second predominant site for thromboembolic symptoms is in the brain, including sinovenous thrombosis.

Endothelin 1 concentrations in infants with meconium stained amniotic fluid.

Plasma endothelin 1 concentrations were determined in infants with meconium stained amniotic fluid. Plasma endothelin 1 concentration in the study group (5.23 pg/ml) was statistically higher than that in the control group (1.12 pg/ml). Cord blood pH and base excess values were significantly lower in infants with meconium stained amniotic fluid when compared with the control group. There was no correlation between endothelin 1 concentrations and pH or base excess values. Results suggest that meconium passage is not a physiological event, even if meconium stained infants appear to be clinically healthy.

Importance of RDW value in differential diagnosis of hypochrome anemias.

Red cell distribution width (RDW) was studied in adults carrying delta-beta thalassemia traits (deltabeta-TT) who were 20-40 years of age (n = 29), beta thalassemia traits (beta-TT) with an age range of 18-60 years (n = 49), iron deficiency anemia (IDA) in individuals aged 1-18 years (n = 27), and in controls with an age range of 20-40 years (n = 20). Although red blood cell count, MCV, and MCH values showed no statistically significant differences between deltabeta-TT and beta-TT, the mean RDW value was significantly higher in deltabeta-TT (20.14 +/- 1.21) compared to beta-TT (14.88 +/- 1.77) (P < 0.001). No difference was observed between the means of RDW in deltabeta-TT and IDA (18.00 +/- 1.94) (P > 0.05). A significant rise in RDW in IDA 5-7 days after initiation of iron therapy (P = 0.00) which was continued to rise up to the 4(th) week of therapy was suggested as an important tool in differentiation of IDA from deltabeta-TT. These observations could be kept in mind in the differential diagnosis of deltabeta-TT from beta-TT and IDA by determining the red blood cell count, red cell indices, and RDW only.

Chronic hemolytic anemia associated with glucose 6-phosphate dehydrogenase (Guadalajara)1 159 C --> T (387 Arg --> Cys) deficiency associated with Gilbert syndrome in a Turkish patient.

The case of an 8-year-old male child with severe kernicterus sequelae is presented in this paper. The child's hemoglobin value varied between 6.0 and 10.8 g/dL and his reticulocyte count ranged between 3.4 and 46.0% during the steady-state condition and hyperhemolytic crisis, respectively. A chronic hemolytic type of red cell G6PD deficiency was diagnosed. DNA studies indicate that the mutation was G6PD Guadalajara 1159 C --> T (387 Arg --> Cys) that is situated at the NADP binding site. Additionally, extra nucleotides of (TA) in the A(TA)n TAA motif of the promoter region of the uridine diphosphate-glucuronosyltransferase gene (UGT-1 A) were found to be homozygous in the patient. The coexistence of Gilbert syndrome with a chronic type of G6PD deficiency was suggested as a cause of neonatal hyperbilirubinemia leading to kernicterus.

Thrombocytopenia and emperipolesis in a patient with hepatitis a infection.

lmmune thrombocytopenia is a benign, self-limiting disease in children, responding well to treatment and generally associated with viral infections. A 13-year-old girl was admitted to a hospital with the epistaxis and purpura after an attack of jaundice 6 weeks before. The diagnosis of hepatitis A virus (HAV)-induced thrombocytopenia was made. Furthermore, erythrophagocytosis by megakaryocytes was demonstrated in the bone marrow of the patient. Although hematologic complications following hepatitis B and C viruses are commonly reported, the association of hepatitis A virus and thrombocytopenia has rarely been described.

Evaluation of coagulation in pediatric bone marrow transplantation patients.

A hypercoagulable state is frequently described in adult patients undergoing bone marrow transplantation (BMT). In this study, the coagulation profile of 29 children was prospectively investigated in the pre- and post-transplant period. A significant rise in the activated partial thromboplastin time (aPTT) values was detected on days 7 and 14 after transplantation. Moreover, an increase in the d-dimer level was also notable, regardless of the clinical condition of the patients. The other coagulation parameters investigated (i.e. protein S, protein C, anti-thrombin III, factor VIII, von Willebrand factor, and prothrombin time) remained essentially unchanged. However, hyper-fibrinogenemia was observed in all patients with chronic myeloid leukemia (CML) (n=5) before and after transplantation. In summary, in the present study pediatric bone marrow transplantation patients did not show a hyper-coagulable state after marrow infusion. However, a significant rise in PTT and d-dimer values were noted.

beta-Thalassaemia intermedia in a Turkish girl: homozygosity for G-->A substitution at +22 relative to the beta-globin cap site.

We provide the first description of a homozygote patient for the G-->A substitution in the 5' UTR of the beta-globin gene. The proband was a 17-year-old girl with beta-thalassaemia intermedia who had never received a blood transfusion. The physical examination revealed a well-developed women with no facial or bony abnormalities. There was mild paleness and mild splenomegaly which was 2 cm below the costal margin. The haemoglobin (Hb) was 7.6 g/dl, Hb A(2) 5.4% and Hb F 14.6% of the total Hb. The Hb A(2) of both parents was 3.5%. The Hb F level in the mother and father were 0.9, 1.2% and the mean cell volume (MCV) value was 70 and 72 fl respectively. DNA analysis of the beta-gene region of the propositus revealed homozygosity for a G-->A substitution at nucleotide +22 relative to the beta-gene cap site, within a functional downstream region that was referred to as the DCE (downstream core element). In addition to the data obtained previously from in vitro transcription assays, clinical findings and in vivo expression studies gave some valuable clues about the effect of +22 G-->A mutation on the expression of beta-gene. Phenotypic expression of this homozygous patient is highly suggestive that G-->A substitution at nt +22 confers a relatively mild (silent) beta(+)-thalassaemia phenotype.

Molecular pathology of haemophilia A in Turkish patients: identification of 36 independent mutations.

Haemophilia A is an X-linked recessive bleeding disorder caused by heterogeneous mutations in the factor VIII gene. In an attempt to reveal the molecular pathology of Turkish haemophilia A patients, the coding sequence of the gene, excluding a large portion of exon 14, was amplified from genomic DNA and subjected to denaturing gradient gel electrophoresis prior to DNA sequencing. Fifty-nine haemophilia A patients were included in the study with severe, moderate and mild phenotypes observed in 24, 15 and 16 patients, respectively. Factor VIII activity and clinical phenotypes were not available for four patients. A total of 36 independent mutations were found, with a mutation detection efficacy of 61%. The mutations that were reported for the first time include 20 point mutations, one 8-bp insertion (TCAAGATA) in exon 4 and one large deletion greater than 2.8 kb involving exon 14. The novel point mutations were composed of three nonsense (Ser681Ter, Cys2021Ter and Gln2113Ter), one splicing error (IVS-1G-->A), 15 missense mutations (Lys48Asn; Leu-98Phe; Thr118Ala; Cys248Tyr; Glu456Lys; Asp560Ala; Tyr664Cys; Phe679Leu; Gly691Trp; Asp1769His; Val1857Leu; Gly2026Gln; Arg2163Pro; Asp2288Ala; and Arg2304Leu) and a T deletion in exon 25 that caused a frameshift followed by a stop codon. All missense mutations except Val1857Leu, which maintained a conserved nonpolar R group, occurred at amino acids conserved among four species and were most probably pathogenic. In addition, two sequence changes (IVS3-9C-->T) and (Leu2230Leu) were also detected in patients carrying Val1857Leu and Phe679Leu missense mutations, respectively. Identification of mutation origins in eight sporadic cases revealed an equal sex ratio of mutations.

Factor V Leiden mutation in Turkish patients with homozygous cystathionine beta-synthase deficiency.

Venous and arterial thromboembolism can occur in patients with homocystinuria. Resistance to activated protein C, which is caused by a single point mutation in the gene for factor V, renders an individual at risk for thrombosis. It has been suggested that coexistence of hereditary homocystinuria and factor V Leiden mutation might jointly play a role in the development of thrombosis. We analysed six patients with homocystinuria due to cystathionine beta-synthase deficiency for factor V Leiden and prothrombin G20210A mutations. Only one patient was found to have the factor V Leiden mutation in homozygous form and this patient had suffered from severe thrombosis. One patient was found to be heterozygous with no documented thrombosis. None of the patients had prothrombin G20210A mutation. We stress the necessity for screening for known thrombophilic risk factors in patients with cystathonine beta-synthase deficiency. The coexistence of the factor V Leiden mutation can cause severe thrombotic events in patients with homocystinuria.