Dehydrated hereditary stomatocytosis is a genetic condition with defective red blood cell membrane properties that causes an imbalance in intracellular cation concentrations. Recently, two missense ...mutations in the mechanically activated PIEZO1 (FAM38A) ion channel were associated with dehydrated hereditary stomatocytosis. However, it is not known how these mutations affect PIEZO1 function. Here, by combining linkage analysis and whole-exome sequencing in a large pedigree and Sanger sequencing in two additional kindreds and 11 unrelated dehydrated hereditary stomatocytosis cases, we identify three novel missense mutations and one recurrent duplication in PIEZO1, demonstrating that it is the major gene for dehydrated hereditary stomatocytosis. All the dehydrated hereditary stomatocytosis-associated mutations locate at C-terminal half of PIEZO1. Remarkably, we find that all PIEZO1 mutations give rise to mechanically activated currents that inactivate more slowly than wild-type currents. This gain-of-function PIEZO1 phenotype provides insight that helps to explain the increased permeability of cations in red blood cells of dehydrated hereditary stomatocytosis patients. Our findings also suggest a new role for mechanotransduction in red blood cell biology and pathophysiology.
No F8 genetic abnormality is detected in approximately 1% to 2% of patients with severe hemophilia A (HA) using conventional genetic approaches. In these patients, deep intronic variation or F8 ...disrupting genomic rearrangement could be causal.
The study aimed to identify the causal variation in families with a history of severe HA for whom genetic investigations failed.
We performed whole F8 gene sequencing in 8 propositi. Genomic rearrangements were confirmed by Sanger sequencing of breakpoint junctions and/or quantitative polymerase chain reaction.
A structural variant disrupting F8 was found in each propositus, so that all the 815 families with a history of severe HA registered in our laboratory received a conclusive genetic diagnosis. These structural variants consisted of 3 balanced inversions, 3 large insertions of gained regions, and 1 retrotransposition of a mobile element. The 3 inversions were 105 Mb, 1.97 Mb, and 0.362 Mb in size. Among the insertions of gained regions, one corresponded to the insertion of a 34 kb gained region from chromosome 6q27 in F8 intron 6, another was the insertion of a 447 kb duplicated region from chromosome 9p22.1 in F8 intron 14, and the last one was the insertion of an Xq28 349 kb gained in F8 intron 5.
All the genetically unsolved cases of severe HA in this cohort were due to structural variants disrupting F8. This study highlights the effectiveness of whole F8 sequencing to improve the molecular diagnosis of HA when the conventional approach fails.
Introduction
With current molecular diagnosis, about 1 to 5% of haemophilia A (HA) patients remain genetically unresolved. In these cases, deep intronic variation or structural variation disrupting ...the F8 gene could be causal.
Aim
To identify the causal variation in four genetically unresolved mild‐to‐severe HA patients using an F8 mRNA analysis approach.
Methods
Ectopic F8 mRNA analysis was performed in four unrelated HA patients. An in vitro minigene assay was performed in order to confirm the deleterious splicing impact of each variation identified.
Results
In all probands, mRNA analysis revealed an aberrant splicing pattern, and sequencing of the corresponding intronic region found a deep intronic substitution. Two of these were new variations: c.2113+601G>A and c.1443+602A>G, while the c.143+1567A>G, found in two patients, has previously been reported. The c.1443+602A>G and the c.143+1567A>G variants both led to the creation of a de novo acceptor or donor splice site, respectively. Moreover, the c.143+1567A>G was found in 3/6 patients with genetically unresolved moderate HA registered in our laboratory. Haplotype analysis performed in all patients carrying the c.143+1567A>G variation suggests that this variation could be a recurrent variation. The c.2113+601G>A led to the exonization of a 122‐bp antisense AluY element by increasing the strength of a pre‐existing cryptic 5’ splice site. For each point variation, in vitro splicing analysis confirmed its deleterious impact on splicing of the F8 transcript.
Conclusion
We identified three deep intronic variations, leading to an aberrant mRNA splicing process as HA causing variation.
Heterozygous germline
mutations strongly predispose to leukemia, immunodeficiency, and/or lymphoedema. We describe a series of 79 patients (53 families) diagnosed since 2011, made up of all patients ...in France and Belgium, with a follow up of 2249 patients/years. Median age at first clinical symptoms was 18.6 years (range, 0-61 years). Severe infectious diseases (mycobacteria, fungus, and human papilloma virus) and hematologic malignancies were the most common first manifestations. The probability of remaining symptom-free was 8% at 40 years old. Among the 53 probands, 24 had missense mutations including 4 recurrent alleles, 21 had nonsense or frameshift mutations, 4 had a whole-gene deletion, 2 had splice defects, and 2 patients had complex mutations. There were significantly more cases of leukemia in patients with missense mutations (n=14 of 34) than in patients with nonsense or frameshift mutations (n=2 of 28). We also identify new features of the disease: acute lymphoblastic leukemia, juvenile myelomonocytic leukemia, fatal progressive multifocal leukoencephalopathy related to the JC virus, and immune/inflammatory diseases. A revised International Prognostic Scoring System (IPSS) score allowed a distinction to be made between a stable disease and hematologic transformation. Chemotherapy is of limited efficacy, and has a high toxicity with severe infectious complications. As the mortality rate is high in our cohort (up to 35% at the age of 40), hematopoietic stem cell transplantation (HSCT) remains the best choice of treatment to avoid severe infectious and/or hematologic complications. The timing of HSCT remains difficult to determine, but the earlier it is performed, the better the outcome.
To report the first case of restoration of ovarian activity and live birth after cryopreserved ovarian tissue autograft in a patient without cancer treated by allogeneic bone marrow transplantation.
...Case report.
University hospital.
One woman with homozygous sickle cell anemia.
An orthotopic autotransplantation of ovarian cortical strips was performed after freeze-thawing.
Cryopreservation of ovarian tissue, bone marrow transplantation, ovarian autograft, and restoration of ovarian function.
In autumn 2005, biopsy samples of ovarian tissue were cryopreserved before chemotherapy followed by bone marrow transplantation. In spring 2008, because the patient had been menopausal for 2.5 years as a result of the conditioning therapy, an orthotopic autotransplantation of thawed ovarian cortex was performed. The patient conceived spontaneously in a natural cycle in autumn 2008, and delivered a healthy female child in June 2009.
Cryopreservation of ovarian tissue with subsequent autotransplantation is an emerging procedure for preserving the fertility of young patients with a high risk of premature ovarian failure (POF) resulting from gonadotoxic treatment. This case opens up new perspectives in cases of nonmalignant diseases.
The impact of measurable residual disease (MRD) on cord blood transplantation (CBT) outcomes has remained debated. To address this issue, we assessed the impact of measurable MRD at CBT on outcomes ...in large cohort of patients with acute leukemia. Inclusion criteria included adult patients with acute myeloid (AML) or acute lymphoblastic leukemia (ALL), CBT as first allo‐HCT in first or second complete remission (CR) at transplantation, and known MRD status at the time of CBT. Data from 506 patients were included in the analysis. Among them, 317 patients had AML and 189 had ALL. Positive MRD was reported in 169 (33%) patients while the remaining 337 patients were MRD negative at CBT. At 2 years, relapse incidence was 18% in patients with MRD negativity vs 33% in those with MRD positivity at transplantation (P < .001). Two‐year leukemia‐free survival (LFS) and overall survival (OS) were 57% and 60%, respectively, in MRD negative patients, vs 38% (P < .001) and 48% (P = .004), respectively, in those with MRD positivity. There was no interaction between the impact of MRD on OS and LFS and diagnosis (ie, ALL vs AML), single or double CBT, and reduced‐intensity or myeloablative conditioning. On multivariate analysis, MRD positivity was associated with a higher risk of relapse (HR = 1.8, P = .003), comparable non‐relapse mortality (P = .44), worse LFS (HR = 1.4, P = .008) and a trend towards worse OS (HR = 1.3, P = .065). In conclusion, these data suggest that novel strategies that are aiming to achieve MRD negativity at CBT are needed for leukemic patients with positive MRD pre‐CBT.
Allogeneic stem cell transplantation remains the only curative treatment for sickle cell anemia (SCA), but the place of myeloablative conditioning in the procedure remains to be defined. The aim of ...the present study was to analyze long-term outcomes, including chimerism, SCA-related events and biological data (hemoglobin, reticulocytes, HbS%), and fertility in a French series of 234 SCA patients under 30 years of age who, from 1988 to 2012, received a matched-sibling-donor stem cell transplantation following standardized myeloablative conditioning busulfan, cyclophosphamide and rabbit antithymocyte globulin (ATG). Since the first report of the series (1988-2004), 151 new consecutive patients with SCA have been similarly transplanted. Considering death, non-engraftment or rejection (donor cells <5%) as events, the 5-year event-free survival was 97.9% (95% confidence interval: 95.5-100%), confirming, since the year 2000, an at least 95% chance of cure. In the overall cohort (n=234, median follow up 7.9 years), event-free survival was not associated with age, but chronic-graft-
-host disease (cGvHD) was independently associated with recipient's age >15 years (hazard ratio=4.37;
=0.002) and lower (5-15
20 mg/kg) ATG dose (hazard ratio=4.55;
=0.001). At one year, 44% of patients had mixed chimerism (5-95% donor cells), but those prepared with ATG had no graft rejection. No events related to SCA occurred in patients with mixed chimerism, even those with 15-20% donor cells, but hemolytic anemia stigmata were observed with donor cells <50%. Myeloablative transplantation with matched-sibling donor currently has a higher event-free survival (98%) in patients under 30 years of age than that reported for non-myeloablative conditioning (88%). Nevertheless, the risk of cGvHD in older patients and the need to preserve fertility might be indications for a non-myeloablative conditioning.
Background. Chronic disseminated candidiasis (CDC) is typically observed during neutrophil recovery in patients with acute leukemia and requires protracted antifungal therapy. Objective. Our ...objective was to document the efficacy and tolerance of corticosteroid therapy (CST) in patients with symptomatic CDC, including those who experienced fever and abdominal pain despite ongoing antifungal therapy. Methods. We performed a retrospective, multicenter study involving 10 pediatric and adult patients who experienced ongoing symptomatic CDC despite receipt of appropriate antifungal therapy for whom adjuvant oral CST was initiated. Results. All cases of CDC were proven or probable, as determined on the basis of the European Organization for Research and Treatment of Cancer-Mycosis Study Group definition criteria, and occurred in patients with leukemia. CDC-attributable clinical symptoms resolved with CST, which was started a mean of 33.8 days after antifungal therapy had been initiated. Fever and abdominal pain disappeared a median of 4–5 days, and serum fibrinogen and C-reactive protein levels returned to normal values within 14–30 days. The median duration of hospitalization after CST initiation was 8.8 days. Hepatosplenic microabscesses decreased or disappeared within a mean period of 107 days (range, 30–210 days). No relapses of CDC were observed during a median duration of follow-up of 6.5 years (range, 4–9 years). Conclusions. In children and adults who experience persistently symptomatic CDC despite ongoing receipt of antifungal therapy, CST involving a prednisone equivalent at a dosage of ⩾0.5 mg/kg per day for at least 3 weeks is associated with a prompt resolution of symptoms and of inflammatory response. These findings support the pathophysiological hypothesis that CDC belongs to the spectrum of fungus-related immune reconstitution inflammatory syndrome.
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