Application of a molecular diagnostic algorithm for haemophilia A and B using next-generation sequencing of entire F8, F9 and VWF genes

Currently, molecular diagnosis of haemophilia A and B (HA and HB) highlights the excess risk-inhibitor development associated with specific mutations, and enables carrier testing of female relatives and prenatal or preimplantation genetic diagnosis. Molecular testing for HA also helps distinguish it from von Willebrand disease (VWD). Next-generation sequencing (NGS) allows simultaneous investigation of several complete genes, even though they may span very extensive regions. This study aimed to evaluate the usefulness of a molecular algorithm employing an NGS approach for sequencing the complete F8, F9 and VWF genes. The proposed algorithm includes the detection of inversions of introns 1 and 22, an NGS custom panel (the entire F8, F9 and VWF genes), and multiplex ligation-dependent probe amplification (MLPA) analysis. A total of 102 samples (97 FVIII- and FIX-deficient patients, and five female carriers) were studied. IVS-22 screening identified 11 out of 20 severe HA patients and one female carrier. IVS-1 analysis did not reveal any alterations. The NGS approach gave positive results in 88 cases, allowing the differential diagnosis of mild/moderate HA and VWD in eight cases. MLPA confirmed one large exon deletion. Only one case did have no pathogenic variants. The proposed algorithm had an overall success rate of 99 %. In conclusion, our evaluation demonstrates that this algorithm can reliably identify pathogenic variants and diagnose patients with HA, HB or VWD.

Supplementary Material to this article is available online at www.thrombosis-online.com.

Eltrombopag safety and efficacy for primary chronic immune thrombocytopenia in clinical practice

BACKGROUND

Eltrombopag is effective and safe in chronic immune thrombocytopenia (ITP). However, clinical trials may not accurately reflect what happens in clinical practice. We evaluated the efficacy and safety of eltrombopag in primary chronic ITP in a real-world setting.

METHODS

A total of 164 primary patients with chronic ITP from 40 Spanish centers, who had been treated with eltrombopag, were retrospectively evaluated.

RESULTS

The median age of our cohort (72% women) was 63 yr (interquartile range, IQR, 45-75 yr). The median time with ITP diagnosis was 81 months (IQR, 30-192 months). The median number of therapies prior to eltrombopag was 3 (IQR, 2-4). At the time of eltrombopag start, 45 patients (30%) were receiving concomitant treatment for ITP. Forty-six patients (30%) had bleeding signs/symptoms the month before the treatment started. The median platelet count at eltrombopag initiation was 22 × 10(9) /L (IQR, 8-39 × 10(9) /L). A total of 135 patients (88.8%) achieved a platelet response. The median time to platelet response was 12 d (95% CI, 9-13 d). Maintained platelet response rate during the 15-month period under examination was 75.2%. Twenty-eight patients (18.4%) experienced adverse events, mainly grades 1-2.

CONCLUSION

Eltrombopag is highly effective and well tolerated in unselected patients with primary chronic ITP.

MicroRNA-223 is a novel negative regulator of HSP90B1 in CLL

Background

MicroRNAs are known to inhibit gene expression by binding to the 3′UTR of the target transcript. Downregulation of miR-223 has been recently reported to have prognostic significance in CLL. However, there is no evidence of the pathogenetic mechanism of this miRNA in CLL patients.

Methods

By applying next-generation sequencing techniques we have detected a common polymorphism (rs2307842), in 24% of CLL patients, which disrupts the binding site for miR-223 in HSP90B1 3′UTR. We investigated whether miR-223 directly targets HSP90B1 through luciferase assays and ectopic expression of miR-223. Quantitative real-time polymerase chain reaction and western blot were used to determine HSP90B1 expression in CLL patients. The relationship between rs2307842 status, HSP90B1 expression and clinico-biological data were assessed.

Results

HSP90B1 is a direct target for miR-223 by interaction with the putative miR-223 binding site. The analysis in paired samples (CD19+ fraction cell and non-CD19+ fraction cell) showed that the presence of rs2307842 and IGHV unmutated genes determined HSP90B1 overexpression in B lymphocytes from CLL patients. These results were confirmed at the protein level by western blot. Of note, HSP90B1 overexpression was independently predictive of shorter time to the first therapy in CLL patients. By contrast, the presence of rs2307842 was not related to the outcome.

Conclusions

HSP90B1 is a direct target gene of miR-223. Our results provide a plausible explanation of why CLL patients harboring miR-223 downregulation are associated with a poor outcome, pointing out HSP90B1 as a new pathogenic mechanism in CLL and a promising therapeutic target.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1212-2) contains supplementary material, which is available to authorized users.

Successful discontinuation of eltrombopag after complete remission in patients with primary immune thrombocytopenia

Eltrombopag is effective and safe in immune thrombocytopenia (ITP). Some patients may sustain their platelet response when treatment is withdrawn but the frequency of this phenomenon is unknown. We retrospectively evaluated 260 adult primary ITP patients (165 women and 95 men; median age, 62 years) treated with eltrombopag after a median time from diagnosis of 24 months. Among the 201 patients who achieved a complete remission (platelet count >100 × 10(9) /l), eltrombopag was discontinued in 80 patients. Reasons for eltrombopag discontinuation were: persistent response despite a reduction in dose over time (n = 33), platelet count >400 × 10(9) /l (n = 29), patient's request (n = 5), elevated aspartate aminotransferase (n = 3), diarrhea (n = 3), thrombosis (n = 3), and other reasons (n = 4). Of the 49 evaluable patients, 26 patients showed sustained response after discontinuing eltrombopag without additional ITP therapy, with a median follow-up of 9 (range, 6-25) months. These patients were characterized by a median time since ITP diagnosis of 46.5 months, with 4/26 having ITP < 1 year. Eleven patients were male and their median age was 59 years. They received a median of 4 previous treatment lines and 42% were splenectomized. No predictive factors of sustained response after eltrombopag withdrawal were identified. Platelet response following eltrombopag cessation may be sustained in an important percentage of adult primary ITP patients who achieved CR with eltrombopag. However, reliable markers for predicting which patients will have this response are needed.

Molecular characterization of chronic lymphocytic leukemia patients with a high number of losses in 13q14

Background

Patients with chronic lymphocytic leukemia and 13q deletion as their only FISH abnormality could have a different outcome depending on the number of cells displaying this aberration. Thus, cases with a high number of 13q- cells (13q-H) had both shorter overall survival and time to first therapy. The goal of the study was to analyze the genetic profile of 13q-H patients.

Design and Methods:

A total of 102 samples were studied, 32 of which served as a validation cohort and five were healthy donors.

Results

Chronic lymphocytic leukemia patients with higher percentages of 13q- cells (>80%) showed a different level of gene expression as compared to patients with lower percentages (<80%, 13q-L). This deregulation affected genes involved in apoptosis and proliferation (BCR and NFkB signaling), leading to increased proliferation and decreased apoptosis in 13q-H patients. Deregulation of several microRNAs, such as miR-15a, miR-155, miR-29a and miR-223, was also observed in these patients. In addition, our study also suggests that the gene expression pattern of 13q-H cases could be similar to the patients with 11q- or 17p-.

Conclusions

This study provides new evidence regarding the heterogeneity of 13q deletion in chronic lymphocytic leukemia patients, showing that apoptosis, proliferation as well as miRNA regulation are involved in cases with higher percentages of 13q- cells.

Identification of a novel recurrent gain on 20q13 in chronic lymphocytic leukemia by array CGH and gene expression profiling

BACKGROUND

The presence of genetic changes is a hallmark of chronic lymphocytic leukemia (CLL). The most common cytogenetic abnormalities with independent prognostic significance in CLL are 13q14, ATM and TP53 deletions and trisomy 12. However, CLL displays a great genetic and biological heterogeneity. The aim of this study was to analyze the genomic imbalances in CLL cytogenetic subsets from both genomic and gene expression perspectives to identify new recurrent alterations.

PATIENTS AND METHODS

The genomic imbalances and expression levels of 67 patients were analyzed. The novel recurrent abnormalities detected with bacterial artificial chromosome array were confirmed by FISH and oligonucleotide microarrays. In all cases, gene expression profiling was assessed.

RESULTS

Copy number alterations were identified in 75% of cases. Overall, the results confirmed FISH studies for the regions frequently involved in CLL and also defined a new recurrent gain on chromosome 20q13.12, in 19% (13/67) of the CLL patients. Oligonucleotide expression correlated with the regions of loss or gain of genomic material, suggesting that the changes in gene expression are related to alterations in copy number.

CONCLUSION

Our study demonstrates the presence of a recurrent gain in 20q13.12 associated with overexpression of the genes located in this region, in CLL cytogenetic subgroups.

A high number of losses in 13q14 chromosome band is associated with a worse outcome and biological differences in patients with B-cell chronic lymphoid leukemia

BACKGROUND

Among patients with B-cell chronic lymphoid leukemia, those with 13q14 deletion have a favorable outcome. However, whether the percentage of cells with 13q- influences the prognosis or the biological characteristics of this disease is unknown. We analyzed the clinico-biological characteristics and outcome of patients with B-cell chronic lymphoid leukemia with loss of 13q as the sole cytogenetic aberration.

DESIGN AND METHODS

Three hundred and fifty patients with B-cell chronic lymphoid leukemia were studied. Clinical data were collected and fluorescence in situ hybridization and molecular studies were carried out. In addition, a gene expression profile was obtained by microarray-based analysis.

RESULTS

In 109 out of the 350 cases (31.1%) loss of 13q was the sole cytogenetic aberration at diagnosis. In the subgroup of patients with 80% or more of cells with loss of 13q (18 cases), the overall survival was 56 months compared with not reached in the 91 cases in whom less than 80% of cells had loss of 13q (p< 0.0001). The variables included in the multivariate analysis for overall survival were the percentage of losses of 13q14 (p=0.001) and B symptoms (p=0.007). The time to first therapy in the group with 80% or more vs. less than 80% of losses was 38 months vs. 87 months, respectively (p=0.05). In the multivariate analysis the variables selected were unmutated status of IgV(H) (p=0.001) and a high level of beta(2)microglobulin (p=0.003). Interestingly, these differences regarding overall survival and time to first therapy were also present when other cut-offs were considered. The gene expression profile of patients with a high number of losses in 13q14 showed a high proliferation rate, downregulation of apoptosis-related genes, and dysregulation of genes related to mitochondrial functions.

CONCLUSIONS

Patients with B-cell chronic lymphoid leukemia with a high number of losses in 13q14 as the sole cytogenetic aberration at diagnosis display different clinical and biological features: short overall survival and time to first therapy as well as more proliferation and less apoptosis. A quantification of the number of cells showing a genetic abnormality should, therefore, be included in the study of the prognostic factors of B-cell chronic lymphoid leukemia.

[Cerebral infarct as a presentation of a hereditary defect of type II C protein]

The case of a 50 year-old patient with a cerebral infarct related to a deficit in type II C protein is described. The patient showed no other vascular risk factor and the cardiological study, which included a transthoracic and a transoesophagic echogram ruled out the presence of embologenic cardiopathy. A family study detected the presence of a deficit of C protein in 6 of the 8 sons and in the patient's sister who had a deep vein thrombosis at the age of 54. A hereditary deficiency in C protein was confirmed. We consider it necessary to perform hypercoagulability studies which include the determination of C protein in patients under 55 years of age with cerebral infarcts of unknown cause, especially when there is a family history of thrombosis.

Blood group polymorphisms and geography in the Sierra de Gredos, Spain

The present research is designed to contribute to our knowledge of the influence of geography on the genetic population structure in the Sierra de Gredos (central Spain). This mountain range separates two distinct areas: the Tormes-Alberche valley in the north and the Tiétar valley in the south. Unrelated blood donors (226), whose 4 grandparents were born in the study area, were tested for blood group markers (A1A2BO, RH, MNSs, Kell, P, and Lewis). R matrix analysis in relation to other Spanish populations agrees reasonably well with the cluster analysis of the Prevosti distance matrix using the UPGMA algorithm. Comparisons suggest a certain degree of genetic variation between the populations of these two valleys. The Sierra de Gredos can thus be considered a biological barrier limiting the gene flow between the valleys.

Serum protein polymorphisms (HP, TF-, GC- and PI subtypes) in two mountain communities of Sierra de Gredos (central Spain)

The genetic variation of four highly polymorphic serum proteins, haptoglobin (HP), transferrin (TF), group-specific component (GC) and alpha-1-antitrypsin (PI) was examined in two representative samples of the autochthonous populations living on either slope of Sierra de Gredos in central Spain. The genetic markers studied do not provide any evidence that the mountain chain has contributed to the maintenance of a genetic differentiation between the two populations. The allele frequency distributions in these Gredos samples are discussed in relation to the variability of these markers in the Iberian Peninsula populations.