Exome Sequencing Identifies Abnormalities in Glycosylation and ANKRD36C in Patients with Immune-Mediated Thrombotic Thrombocytopenic Purpura

2020 ◽  
Author(s):  
Malay Kumar Basu ◽  
Felipe Massicano ◽  
Lijia Yu ◽  
Konstantine Halkidis ◽  
Vikram Pillai ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Disease Onset ◽  
Protein Glycosylation ◽  
Healthy Controls ◽  
Major Pathway ◽  
Thrombocytopenic Purpura ◽  
Hematological Disorders ◽  
Blood Disorder ◽  
Immune Mediated

Abstract Background Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal blood disorder, resulting from autoantibodies against ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13). However, the mechanism underlying anti-ADAMTS13 autoantibody formation is not known, nor it is known how genetic aberrations contribute to the pathogenesis of iTTP. Methods Here we performed whole exome sequencing (WES) of DNA samples from 40 adult patients with iTTP and 15 local healthy subjects with no history of iTTP and other hematological disorders. Results WES revealed variations in the genes involved in protein glycosylation, including O-linked glycosylation, to be a major pathway affected in patients with iTTP. Moreover, variations in the ANKRD gene family, particularly ANKRD36C and its paralogs, were also more prevalent in patients with iTTP than in the healthy controls. The ANKRD36 family of proteins have been implicated in inflammation. Mass spectrometry revealed a dramatic alternation in plasma glycoprotein profile in patients with iTTP compared with the healthy controls. Conclusion Altered glycosylation may affect the disease onset and progression in various ways: it may predispose patients to produce ADAMTS13 autoantibodies or affect their binding properties; it may also alter clearance kinetics of hemostatic and inflammatory proteins. Together, our findings provide novel insights into plausible mechanisms underlying the pathogenesis of iTTP.

Exome Sequencing Identifies Glycosylation Defects as a Probable Cause of Immune-Mediated Thrombotic Thrombocytopenic Purpura

2019 ◽  
Vol 152 (Supplement_1) ◽  
pp. S19-S20
Author(s):  
Malay Kumar Basu ◽  
Elizabeth Staley ◽  
Konstantine Halkidis ◽  
Jingrui (Jean) Sui ◽  
Nicole K Kocher ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Potential Contribution ◽  
Healthy Controls ◽  
Adamts13 Activity ◽  
Autoantibody Production ◽  
Thrombocytopenic Purpura ◽  
Long Term Outcome ◽  
Immune Mediated ◽  
Severe Deficiency

Abstract Background Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal syndrome, resulting from autoantibodies against ADAMTS13. However, the mechanism underlying autoantibody formation is not known. Neither is known about the other genetic abnormality in the setting of severe deficiency of plasma ADAMTS13 activity. Methods Whole-exome sequencing (WES) was performed in 40 patients with iTTP who had plasma ADAMTS13 activity <10% and a positive inhibitor or elevated anti-ADAMTS13 IgG. Fifteen age- and ethnicity-matched subjects who never had iTTP were recruited as healthy controls. Results WES identified mutations in the genes involved in glycosylation, including O-linked glycosylation to be the major pathway affected in patients with iTTP. Mass spectrometry confirmed the changes in plasma levels of various glycoproteins in patients with acute iTTP when compared with those in the healthy controls. The altered glycosylation in glycoproteins may be responsible for the development of autoantibodies, susceptibility of von Willebrand factor to proteolysis by ADAMTS13, and the clearance of platelets in iTTP patients. Moreover, candidate gene analysis revealed that various genes involving in hemostasis, complement activation, platelet number and function, and inflammation were all affected in patients with iTTP, which may contribute to the onset, progress, severity, and long-term outcome of iTTP. Conclusions Our findings provide novel insight into a pathogenic mechanism underlying autoantibody production and the potential contribution of other genetic abnormalities in pathogenesis of iTTP in the individuals with severe deficiency of plasma ADAMTS13 activity. Future Direction Further studies are warranted to determine the specific glycosylation patterns of various plasma and cellular proteins in patients with iTTP and to determine the synergistic role of various gene mutations and severe ADAMTS13 deficiency in the pathogenesis of iTTP.

scholarly journals Insights from the Hereditary Thrombotic Thrombocytopenic Purpura Registry: Discussion of Key Findings Based on Individual Cases from Switzerland

2020 ◽  
Vol 40 (S 01) ◽  
pp. S5-S14
Author(s):  
Johanna A. Kremer Hovinga ◽  
Thomas R. Braschler ◽  
Florian Buchkremer ◽  
Stefan Farese ◽  
Heinz Hengartner ◽  
...  
Keyword(s):  
Cohort Study ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Disease Onset ◽  
Myocardial Infarctions ◽  
Thrombocytopenic Purpura ◽  
Blood Disorder ◽  
A Disintegrin And Metalloproteinase ◽  
Systematic Collection ◽  
Plasma Infusions

AbstractThe Hereditary TTP Registry is an international cohort study for patients with a confirmed or suspected diagnosis of hereditary thrombotic thrombocytopenic purpura (hTTP) and their family members. Hereditary TTP is an ultra-rare blood disorder (prevalence of ∼1–2 cases per million), the result of autosomal-recessively inherited congenital ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) deficiency (ADAMTS13 activity <10% of the normal), and associated with yet many unanswered questions. Until December 2017, the Hereditary TTP Registry had enrolled 123 confirmed hTTP patients. Their median age at disease onset was 4.5 years (range: 0–70) and at clinical diagnosis 16.7 years (range: 0–69), a difference that highlights the existing awareness gap in recognizing hTTP. The systematic collection of clinical data of individual patients revealed their substantial baseline comorbidities, as a consequence of recurring TTP episodes in the past. Most notable was the high proportion of patients having suffered from premature arterial thrombotic events, mainly transient ischemic attacks, ischemic strokes, and to a lesser extent myocardial infarctions. At 40 to 50 years of age and above, more than 50% of patients had suffered from at least one such event, and many had experienced arterial thrombotic events despite regular plasma infusions every 2 to 3 weeks that supplements the missing plasma ADAMTS13. The article by van Dorland et al. (Haematologica 2019;104(10):2107–2115) and the ongoing Hereditary TTP Registry cohort study were recognized with the Günter Landbeck Excellence Award at the 50th Hemophilia Symposium in Hamburg in November 2019, the reason to present the Hereditary TTP Registry in more detail here.

scholarly journals The HLA Variant rs6903608 Is Associated with Disease Onset and Relapse of Immune-Mediated Thrombotic Thrombocytopenic Purpura in Caucasians

2020 ◽  
Vol 9 (10) ◽  
pp. 3379
Author(s):  
Ilaria Mancini ◽  
Elisa Giacomini ◽  
Silvia Pontiggia ◽  
Andrea Artoni ◽  
Barbara Ferrari ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Risk Allele ◽  
Absolute Risk ◽  
Disease Onset ◽  
Close Monitoring ◽  
Reference Allele ◽  
Thrombocytopenic Purpura ◽  
Immune Mediated ◽  
The Impact ◽  
Risk Of Relapse

Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is a rare, life-threatening thrombotic microangiopathy caused by severe ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin motifs 13) deficiency, recurring in 30–50% of patients. The common human leukocyte antigen (HLA) variant rs6903608 was found to be associated with prevalent iTTP, but whether this variant is associated with disease relapse is unknown. To estimate the impact of rs6903608 on iTTP onset and relapse, we performed a case-control and cohort study in 161 Italian patients with a first iTTP episode between 2002 and 2018, and in 456 Italian controls. Variation in rs6903608 was strongly associated with iTTP onset (homozygotes odds ratio (OR) 4.68 (95% confidence interval (CI) 2.67 to 8.23); heterozygotes OR 1.64 (95%CI 0.95 to 2.83)), which occurred over three years earlier for each extra risk allele (β −3.34, 95%CI −6.69 to 0.02). Of 153 survivors (median follow-up 4.9 years (95%CI 3.7 to 6.1)), 44 (29%) relapsed. The risk allele homozygotes had a 46% (95%CI 36 to 57%) absolute risk of relapse by year 6, which was significantly higher than both heterozygotes (22% (95%CI 16 to 29%)) and reference allele homozygotes (30% (95%CI 23 to 39%)). In conclusion, HLA variant rs6903608 is a risk factor for both iTTP onset and relapse. This newly identified biomarker may help with recognizing patients at high risk of relapse, who would benefit from close monitoring or intensified immunosuppressive therapy.

scholarly journals Identification of Biomarkers in Patients with Thrombotic Thrombocytopenic Purpura Presenting with Large and Small Ischemic Stroke

2021 ◽  
pp. 29-36
Author(s):  
Chen Lin ◽  
Raima Memon ◽  
Jingrui Sui ◽  
X. Long Zheng
Keyword(s):  
Ischemic Stroke ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Clinical Information ◽  
Organ Damage ◽  
Neutrophil Extracellular Trap ◽  
Maximum Diameter ◽  
Thrombocytopenic Purpura ◽  
Blood Disorder ◽  
Immune Mediated ◽  
Laboratory Confirmation

Background: Thrombotic thrombocytopenic purpura (TTP) is a rare blood disorder resulting in organ damage including ischemic strokes. We sought to characterize the neuroimaging patterns of stroke in a large cohort of patients with immune-mediated TTP (iTTP) and determined their associations with clinical and laboratory parameters and outcomes. Methods: We analyzed the Alabama TTP Registry who had laboratory confirmation of acute iTTP. We reviewed the neuroimaging patterns of those with ischemic stroke on MRI, clinical information, and laboratory results. Small ischemic strokes were ≤20 mm in their maximum diameter in the axial plane. Large ischemic strokes were >20 mm. Student t test, Mann-Whitney U test, and χ2 test were all used for data analysis. Results: Of 108 iTTP patients, 21 had ischemic stroke on neuroimaging. The median platelet count in these patients was 12 × 109/L (interquartile range, IQR, 8.8–21 × 109/L), plasma ADAMTS13 activity 1.8 U/dL (IQR 0–4.5 U/dL), and the mean plasma level of anti-ADAMTS13 IgG was 6,595.8 U/mL (SD 3,448.9 U/mL). Comparison between patients with large ischemic strokes (n = 10) and small ischemic strokes (n = 11) revealed that patients with small stroke were older (p = 0.043) and had higher plasma levels of citrullinated histone 3 (p = 0.006) and histone/DNA complex (p = 0.014) than those with large strokes. There were no significant differences between 2 stroke groups in mortality or exacerbation. Conclusions: iTTP patients can present with large ischemic strokes and are usually younger. Further research should be performed in assessing different etiologies of iTTP-associated stroke based on neutrophil extracellular trap formation biomarkers (e.g., histone markers) seen in small ischemic stroke.

Dasatinib-induced immune mediated-thrombotic thrombocytopenic purpura

2018 ◽  
Vol 57 (2) ◽  
pp. 222-224 ◽  
Author(s):  
Esra Terzi Demirsoy ◽  
Ozgur Mehtap ◽  
Elif Birtas Atesoglu ◽  
Pinar Tarkun ◽  
Necmi Eren ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Thrombocytopenic Purpura ◽  
Immune Mediated

Carboxiterminal pro-endothelin-1 as an endothelial cell biomarker in thrombotic thrombocytopenic purpura

2016 ◽  
Vol 115 (05) ◽  
pp. 1034-1043 ◽  
Author(s):  
György Sinkovits ◽  
Péter Farkas ◽  
Dorottya Csuka ◽  
Katalin Rázsó ◽  
Marienn Réti ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Acute Phase ◽  
Complement Activation ◽  
Endothelial Activation ◽  
Factor H ◽  
Healthy Controls ◽  
Activation Markers ◽  
Thrombocytopenic Purpura ◽  
Endothelin 1

SummaryThrombotic thrombocytopenic purpura (TTP) is characterised by the deficiency of the von Willebrand factor (VWF) cleaving protease (ADAMTS-13). Although several observations indicate an important role of endothelial activation in the pathogenesis of TTP, no reliable endothelial activation markers are available in the clinical management of TTP. Our aim was to investigate the presence of endothelial activation in TTP and to determine its connections with disease activity, therapy and complement activation. We enrolled 54 patients (median age 40.5; 44 females) and 57 healthy controls (median age 34; 30 females),VWF antigen, carboxiterminal-pro-endothelin-1 (CT-proET-1), complement Factor H and complement activation products (C3bBbP and SC5b-9) were measured. In both the acute and remission phase of TTP we found increased CT-proET-1 and VWF levels, while Factor H levels decreased compared with healthy controls. In remission, however, the elevated CT-proET-1 levels showed 22 % decrease when compared with the acute phase in paired samples (p=0.0031), whereas no changes for VWF and Factor H levels were observed. We also found positive correlations between CT-proET-1 levels and alternative pathway activation markers (C3bBbP; p=0.0360; r=0.4299). The data we present here demonstrate a role of endothelium activation in patients with acute TTP. The finding that CT-proET-1 levels decreased in remission compared with the acute phase further supports endothelial involvement. In addition, we show that endothelial activation also correlated with the activation of the alternative complement pathway. The data suggest that complement and endothelium activation jointly contribute to the development of TTP episodes in patients with predisposition to TTP.Supplementary Material to this article is available online at www.thrombosis-online.com.

scholarly journals Exome Sequencing Identifies Glycosylation Defects As a Probable Cause of Immune Thrombotic Thrombocytopenic Purpura

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 217-217
Author(s):  
Felipe Massicano ◽  
Elizabeth M. Staley ◽  
Konstantine Halkidis ◽  
Nicole K. Kocher ◽  
Lance A. Williams ◽  
...  
Keyword(s):  
Exome Sequencing ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Potential Contribution ◽  
Severe Thrombocytopenia ◽  
Adamts13 Activity ◽  
Genomic Alterations ◽  
Autoantibody Production ◽  
Thrombocytopenic Purpura ◽  
Long Term Outcome ◽  
Clinical Presentations

Background: Immune thrombotic thrombocytopenic purpura (iTTP) is a potentially fatal syndrome, resulting primarily from autoantibodies against ADAMTS13. However, the mechanism underlying the autoantibody formation and the contribution of other genomic alterations to the pathogenesis of iTTP are largely unknown. Methods: Whole exome sequencing (WES) and bioinformatic analyses were performed to determine the genetic variations in 40 patients with iTTP who had ADAMTS13 activity &lt;10 IU/dL and a positive inhibitor or an elevated anti-ADAMTS13 IgG in concordance with clinical presentations of severe thrombocytopenia and microangiopathic hemolytic anemia with various degrees of organ injury. WES was also performed at the same time in fifteen age-, gender-, and ethnicity- matched individuals who did not have a history of iTTP or other hematological disorders as controls. Results: WES identified variants or mutations in the genes involving in glycosylation, including O-linked glycosylation, to be the major pathway affected in patients with iTTP. We propose that the altered glycosylation may be responsible for the development of autoantibodies against ADAMTS13 which impair the proteolytic cleavage of von Willebrand factor, accelerate the clearance of ADAMTS13 from circulation, and result in severe thrombocytopenia platelets in patients with iTTP. We also identified defects in ankyrin repeat containing protein ANKRD36C, a protein with hitherto unknown function, as the most statistically significant genomic alterations associated with iTTP (p &lt; 10-5). Moreover, candidate gene analysis revealed that various genes involving in hemostasis, complement activation, platelet function and signaling pathway, and inflammation were all affected in patients with iTTP, which may contribute to the onset, progress, severity, and long-term outcome of iTTP. Finally, we also identified two patient subgroups where the disease mechanism might be different. Conclusion: Our findings provide novel insight into the pathogenic mechanism underlying ADAMTS13 autoantibody production and the potential contribution of other genetic abnormalities in modifying the iTTP clinical presentations in the individuals with severe deficiency of plasma ADAMTS13 activity. Disclosures Zheng: Alexion: Speakers Bureau; Ablynx/Sanofi: Consultancy, Speakers Bureau; Shire/Takeda: Research Funding; Clotsolution: Other: Co-Founder.

scholarly journals Annual Incidence and Severity of Acute Episodes in Hereditary Thrombotic Thrombocytopenic Purpura

Blood ◽  
2021 ◽  
Author(s):  
Erika Tarasco ◽  
Lukas Bütikofer ◽  
Kenneth D. Friedman ◽  
James N George ◽  
Ingrid V Hrachovinova ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Disease Onset ◽  
Premature Death ◽  
Annual Incidence ◽  
Prospective Data ◽  
Thrombocytopenic Purpura ◽  
Adamts13 Deficiency ◽  
Survival Frequency ◽  
Overt Disease ◽  
Plasma Infusions

Hereditary thrombotic thrombocytopenic purpura (hTTP) is a rare thrombotic microangiopathy characterized by severe congenital ADAMTS13 deficiency and recurring acute episodes causing morbidity and premature death. Information on the annual incidence and severity of acute episodes in hTTP patients is largely lacking. This study reports prospective data of 87 patients from the Hereditary TTP Registry (ClinicalTrials.gov NCT01257269) for survival, frequency and severity of acute episodes from enrollment until December 2019. The 87 patients, followed for median 4.2 years (range 0.01-15), had a median age at overt disease onset and at clinical diagnosis of 4.6 years and of 18 years (range 0.0-70 for both), respectively. Forty-three patients received regular plasma prophylaxis, while 22 did not, and treatment changed over time or was unknown in the remaining 22. Forty-three patients experienced 131 acute episodes of which 91 (69%) occurred in patients on regular prophylaxis. This resulted in an annual incidence of acute episodes of 0.36 (95%CI 0.29-0.44) with and of 0.41 (95%CI 0.30-0.56) without regular plasma treatment. More than one third of acute episodes (n=51) were documented in children &lt;10 years of age at enrollment and were often triggered by infections. Their annual incidence of acute episodes was significantly higher than in patients &gt;40 years of age (1.18 [95% CI 0.88-1.55] vs. 0.14 [95% CI 0.08-0.23]). Prophylactic plasma infusion regimens used were insufficient to prevent acute episodes in many patients. Such regimens are burdensome, caregivers, patients and their guardians are reluctant to start regular plasma infusions, from which particularly children would benefit.

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