Prednisolone treatment induced temporary factor IX normalization in mild hemophilia B who required an epidural infiltration: A case report.

A 31-year-old man with mild hemophilia B developed a herniated disc treated with prednisolone for back pain. Surprisingly, hemostasis result tests performed before epidural infiltration were a normal activated partial thrombin time at 36.1 s. (normal range 27.9-37.7 s.) and factor IX (FIX) level 76% (normal range>70%), 13 days after prednisolone introduction. After a second control with a normal FIX level and a second genetic confirmation of hemophilia, no FIX concentrates was administered to perform the infiltration, which occurred without hemorrhagic complication. This new case of FIX normalization showed the necessity to have a perfect knowledge of patient's treatment to avoid misdiagnosis and a temporary normal hemostasis permit to perform epidural infiltration without replacement therapy.

Recurrent F8 and F9 gene variants result from a founder effect in two large French haemophilia cohorts.

INTRODUCTION: Haemophilia A (HA) and haemophilia B (HB) are X-linked recessive diseases, caused by a large number of pathogenic variants in the F8 and F9 genes. With the exception of introns 22 and 1 inversions which are frequent in severe HA cases, about 2000 unique variants in F8 and 1000 in F9 have been described in databases and their recurrence remains limited. AIM AND METHODS: During routine analysis, we identified two recurrent missense variants, the F8 gene c.1244C>T, p.Ala415Val variant in 27 HA patients and the F9 gene c.835G>A, p.Ala279Thr variant in 34 HB patients, in two groups of haemophiliac patients from two different regions of France. We aimed to identify whether these variants result from a founder effect. We performed haplotype reconstruction after analysis of extragenic and intragenic polymorphic markers. The ESTIAGE programme was used to estimate the age of the variant. RESULTS: We identified a common ancestral haplotype HA1, in all the HA patients sharing the p.Ala415Val variant, and HB1 for 22 of 34 HB patients sharing the p.Ala279Thr variant. The estimated time of occurrence of the founder variant was between the 13th and 17th century (95% CI: 16 to 29 generations) for the F8 variant and between the 3rd and the 11th century for the F9 variant (95% CI: 44 to 72 generations). CONCLUSION: This study supports a founder effect for these two variants in the two largest reported cohorts of haemophilia patients with an identical variant. These pathogenic variants are among the three most early reported variants in haemophilia.

Molecular cytogenetic characterization of five F8 complex rearrangements: utility for haemophilia A genetic counselling.

BACKGROUND: Genomic inversions are usually balanced, but unusual patterns have been described in haemophilia A (HA) patients for intron 22 (Inv22) and intron 1 (Inv1) inversions leading to the hypothesis of more complex rearrangements involving deletions or duplications. AIM: To characterize five abnormal patterns either in Southern blot and long-range PCR for Inv22 or in PCR for Inv1. MATERIALS AND METHODS: All patients were studied using cytogenetic microarray analysis (CMA). RESULTS: In all cases, CMA analysis found that each inversion was associated with complex Xq28 rearrangement. In three patients, CMA analysis showed large duplication ranging from 230 to 1302 kb and encompassing a various number of contiguous genes among which RAB39B. RAB39B duplication is a strong candidate gene for X-linked intellectual disability (XLID). Surprisingly, none of the severe HA patients with RAB39B duplication reported in this study or in the literature exhibited XLID. We hypothesise that F8 complex rearrangement down regulated RAB39B expression. In the two remaining patients, CMA analysis found Xq28 large deletion (from 285 to 522 kb). Moyamoya syndrome was strongly suspected in one of them who carried BRCC3 deletion. CONCLUSION: Because several F8 neighbouring genes are associated with other pathologies such as XLID and cardiovascular disease, all HA patients where complex Xq28 rearrangement was suspected should be referred to a geneticist for possible utility of a pangenomic study. Such investigation should be carefully considered in genetic counselling in female carriers to assess the risk of transmitting severe HA with a "contiguous gene syndrome".

Study of six patients with complete F9 deletion characterized by cytogenetic microarray: role of the SOX3 gene in intellectual disability.

Essentials Some hemophilia B (HB) patients with complete F9 deletion present with intellectual disability (ID). We delineate six F9 complete deletions and investigate genotype/phenotype correlation. We identify SOX3 as a candidate gene for ID, acting through haploinsufficiency, in HB patients. All complete F9 deletions in ID patients should be explored with cytogenetic microarrays. SUMMARY: Background Large deletions encompassing both the complete F9 gene and contiguous genes have been detected in patients with severe hemophilia B (HB). Some of these patients present other clinical features, such as intellectual disability (ID). Objectives/Methods In this study, we characterized six unrelated large deletions encompassing F9, by cytogenetic microarray analysis (CMA), to investigate genotype/phenotype correlation. Results Five of the six patients included in this study presented with ID associated with HB. CMA showed that the six large deletions, ranging in size from approximately 933 kb to 9.19 Mb, were located within the Xq26.3 to Xq28 bands. In all cases, the complete deletion of F9 was associated with the loss of various neighboring genes (5-28 other genes). The smallest region of overlap for ID was a 1.26-Mb region encompassing seven OMIM genes (LOC389895, SOX3, LINC00632, CDR1, SPANXF1, LDOC1, SPANXC). SOX3, our candidate gene for ID, encodes an early transcription factor involved in pituitary development. All of the patients studied who had both HB and ID had deletion of the SOX3 gene. Conclusions All HB patients with an atypical phenotype, especially if complete deletion of F9 is suspected, should be referred to a geneticist for possible pangenomic assessment, because haploinsufficiency of genes flanking F9, such as SOX3 in particular, may result in a broader phenotype, including ID. Such assessment would be of particular value for the genetic counseling of female carriers with F9 deletions, as it would facilitate analysis of the risk of transmitting HB associated with ID.

Characterization of five associations of F8 missense mutations containing FVIII B domain mutations.

INTRODUCTION: Haemophilia A (HA) is a bleeding disorder due to an absence or a reduced activity of coagulation factor VIII (FVIII) caused by mutations in F8 gene. Missense mutations represent approximately 45% of the reported molecular defects in HA. However, only few missense mutations in FVIII B domain have been described. AIM: The aim of this study was to characterize five genetic variations (three novels and two previously reported) localized in the FVIII B domain. In all cases, an additional missense variation located outside the FVIII B domain was found. We investigated each of these variations separately and in combination too for their contribution to HA phenotype. METHODS: F8 variants were transiently expressed in COS-1 cells. Media and cell lysates were collected after 72 h. Then, FVIII activity, secretion and thermostability were analysed and compared to FVIII wild-type. RESULTS: The 5 FVIII B domain variants showed normal FVIII: C (98.5-128.5%) and FVIII: Ag (97.7-154%). No synergistic effect was observed between the B domain variant and their associated mutations. In contrast, the variants located outside the B domain, p.V682L, p.S714L, p.V592D and p.C573F revealed significantly decrease of FVIII: C with values in the range 3.5-44.5% (p < 0.05). However, the p.G224R variant showed FVIII: C and FVIII: Ag values no significantly different from FVIII-WT. CONCLUSION: The FVIII B domain variants, p.D963N, p.S806T, p.G873D, p.H998Q and p.Q1225R may be considered as polymorphism or non-pathologic mutations. In five patients, clinical phenotype could be explained by the additional causative missense mutation. For the p.G224T variant further splicing studies are necessary to determine its pathogenicity.

Usefulness of an in vitro cellular expression model for haemophilia A carrier diagnosis: illustration with five novel mutations in the F8 gene in women with isolated factor VIII:C deficiency.

This study aims to determine the way to predict the haemophilia A (HA) carrier status and the potential severity in six females with low FVIII: C levels (<0.50 IU mL(-1) ), F8 gene variations and without family history of HA. Except p.Ser577Tyr, F8 gene variations that we reported have never been described (p.Leu107His, p.Pro521Leu, p.Val682Leu, p.Leu2032Pro, p.Ala315dup). Prediction of their potential causal impact was studied by two strategies: bioinformatics approaches and site-directed mutagenesis followed by FVIII cellular expression into COS-1 cell. FVIII clotting assay ( FVIII: C) and antigen ( FVIII: Ag) were assayed in vitro. In silico analysis showed the probably damaging effect of all substitutions and the full conservation of the residues across mammalian species, except for p.Leu2032Pro. The in vitro variant expression model showed abnormal intra and/or extracellular FVIII: C and FVIII: Ag levels for five mutations, which suggest their causality in HA and provide informations about the involved mechanism. We suspect a defect in synthesis and secretion for p.Leu107His, p.Ala315dup and p.Pro521Leu. The mutation p.Val682Leu only affects the FVIII function while p.Ser577Tyr alters function and synthesis. The variant p.Leu2032Pro is probably a polymorphism because no alteration of the FVIII protein expression was observed in vitro. In vitro results suggest that mutations p.Ser577Tyr and p.Ala315dup could led to a severe HA in men. This study demonstrates the ability of this in vitro cellular expression model to contribute to the diagnosis strategy for female suspected of being HA carrier, without HA family history and with a novel F8 gene variation and to provide new criteria for the genetic counselling.

Diagnosis and management challenges in patients with mild haemophilia A and discrepant FVIII measurements.

Thirty per cent of patients with mild haemophilia A (MHA) present markedly different FVIII: C level when assayed by one-stage clotting and two-stage chromogenic assays. It is, therefore, a real clinical challenge to predict the individual bleeding risk of these patients. The aim of the present work was to study the relationship between the bleeding tendency of these patients with the results of a panel of phenotypic and genotypic tools. Thirty-six patients with MHA were included in this multicentre prospective clinical study. The severity of bleeding symptoms was evaluated using the ISTH/SSC score. FVIII:C levels were measured using an activated partial thromboplastin time-based one-stage FVIII assay (FVIII: C1) and three commercial chromogenic kits (FVIII:CR). FVIII antigen levels, thrombin generation measurement and FVIII gene mutation analysis were also performed. Our results showed that a one-stage FVIII: C assay cannot rule out the diagnosis of MHA, a combined use of FVIII:C1 with a FVIII:CR is suitable for detecting MHA. We observed that FVIII:CR results better reflected the clinical bleeding tendency of patients compared to FVIII:C1. We also observed a relationship between thrombin generation (TG) capacity and FVIII:CR of these patients. FVIII gene mutation analysis showed mutations previously reported in MHA patients with discrepant FVIII:C measurements, but with no predictive value of the individual bleeding phenotype of patients. Overall, we observed a relationship between chromogenic FVIII:C results, TG assay and bleeding tendency of patients with discrepant FVIII:C measurements, while FVIII:C1 was not well correlated with clinical bleeding phenotype in this particular population.

Management of bleeding in severe factor V deficiency with a factor V inhibitor.

Factor V (FV) inhibitor arises rarely after using fresh frozen plasma (FFP) to treat inherited FV deficiency and is often a real therapeutic challenge. Here, we report a patient with a severe FV deficiency who developed such an inhibitor and was then treated with recombinant activated FVII (rFVIIa) and platelet concentrates (PC). Monitoring was assessed by thrombin generation assay (TGA). PC were more effective than rFVIIa in treating bleeding, but there was no correlation between the TGA results and clinical efficacy.

Characterization of four novel molecular changes in the promoter region of the factor VIII gene.

Haemophilia A (HA) is an X-linked recessive bleeding disorder, caused by a wide variety of mutations in the factor VIII (F8) gene, leading to deficiency in the activity of coagulation FVIII. These mutations can affect all the F8 exons from the initiation codon to the termination codon, however, only few molecular changes in the promoter region of the F8 gene were reported so far. Here, we describe six nucleotide variations (c.-51G>A, c.-218T>C, c.-219C>T, c.-219delC, c.-221T>A and c.-664G>A) detected in the F8 promoter and their correlation with clinical phenotype of the patients. Potential role of these mutations in HA was also assessed. Causality was demonstrated with transient transfection experiments using luciferase reporter gene plasmids and computational analysis. Two molecular changes (c.-51G>A and c.-664G>A) did not seem to affect the promoter function of the F8 gene whereas c.-218T>C, c.-219C>T, c.-219delC, c.-221T>A mutations had an impact on the F8 promoter function and were responsible for HA. Furthermore, these mutations were associated with resistance to 1-deamino-8-D-argininevasopressin (desmopressin) therapy when they were causative. When molecular variation was detected in F8 promoter, we propose to use prediction software and to verify predictions by reporter gene analysis. If the mutation is causative, it will be probably associated with a lack of therapeutic response to desmopressin and this clinical implication should be considered by clinicians.

Evaluation of the coulter LH 750 haematology analyzer compared with flow cytometry as the reference method for WBC, platelet and nucleated RBC count.

The Coulter LH 750 is a new haematology analyser with several new features: a count of nucleated red blood cells (NRBCs), automated WBC correction in presence of a flag indicating a cellular interference and a lower incidence of platelet or WBC interference flags when compared with the GEN.S, our current instrument. We had three main goals in our study: evaluating the LH 750 WBC counts when a GEN.S flag suggests a risk of WBC interference, ascertaining whether the platelet counts not flagged by the LH 750 were accurately assessed in samples flagged by the GEN.S and evaluating the NRBC assay provided by the LH 750. Flow cytometry, using CD45 and CD41, respectively for WBC and platelet labelling, was used as a reference method to assess the accuracy of the LH 750 counts. NRBC were identified by double labelling with propidium iodide (PI) and CD45, NRBCs being CD45-/PI+. A significant relationship was found between LH 750 and flow cytometric WBC counts, whether a WBC correction was made by the LH 750 (r = 0.9809, n = 54) or not (r = 0.9901, n = 23). A highly significant relationship was observed for platelets not only in the range from 0 to 450 x 10(9)/l (r = 0.981, n = 108) but also in cases of thrombocytopenia (range: 0-80 x 10(9)/l; r = 0.956, n = 51). In samples with NRBCs, the NRBC percentages given by the LH 750 and by flow cytometry were highly correlated (r = 0.977, n = 60) and WBC counts were accurate. In conclusion, the reduction in flagging by the LH 750, the accuracy of the results, and the availability of a NRBC count, constitute major advantages.

[Mesenteric vein and inferior vena cava thrombosis: disseminated intravascular coagulation and/or G 20210 A mutation of the prothrombin gene?]. / Thrombose veineuse mésentérique et cave inférieure: CIVD et/ou mutation G 20210 A du gène de la prothrombine?

The authors report the case of a 30-year-old man who died from pulmonary embolism and multiorgan failure caused by mesenteric and inferior vena cava thrombosis. The patient was found heterozygous for the prothrombin gene variant (G 20210 A). The family study showed the same asymptomatic anomaly in his brother. This recently described mutation is associated with an increased risk for venous thrombosis. The investigations and treatment of mesenteric venous thrombosis are discussed.

Comparison of two serological methods and a polymerase chain reaction-enzyme immunoassay for the diagnosis of acute respiratory infections with Chlamydia pneumoniae in adults.

Chlamydia pneumoniae is a common respiratory tract pathogen. Serological methods currently used for the diagnosis of C. pneumoniae infection lack specificity, give ambiguous results from a single serum sample and often provide only a retrospective diagnosis. A prospective study was undertaken to assess whether PCR could be a useful addition to the serological techniques routinely practised for diagnosis. This study investigated 68 adult patients with a diagnosis of acute respiratory infection. Acute and convalescent serological determination of antibodies to C. pneumoniae were performed by means of an rELISA test and a micro-immunofluorescence (MIF) test. Nasopharyngeal aspirates or bronchoalveolar lavage specimens and bronchial aspirates obtained from the 68 patients were evaluated by PCR-enzyme immunoassay (PCR-EIA) for the presence of C. pneumoniae and by immunofluorescence assay and cell culture for virus identification. Mycoplasma pneumoniae serology was also performed. Eight patients (11.8%) were positive by either rELISA or PCR-EIA, or both, with an infection rate of 5 (18.5%) of 27 in patients with community-acquired pneumonia, 2 (9%) of 22 in asthmatic patients and 1 (5%) of 19 in patients with an exacerbation of chronic obstructive pulmonary disease. Serological evidence of acute infection was found in four of these patients with the rELISA test and in three others with the MIF test. PCR-EIA detected C. pneumoniae DNA in four specimens, but there were concordant results with both rELISA and PCR-EIA in only one patient A positive PCR-EIA was also obtained in a patient who did not show an antibody response in acute serum. The discrepancy between serological and PCR-EIA results reflects the difficulties in routine laboratory diagnosis of C. pneumoniae infection and the necessity for further studies with optimised techniques.