scholarly journals Single-nucleotide variations defining previously unreportedADAMTS13haplotypes are associated with differential expression and activity of the VWF-cleaving protease in a Salvadoran congenital thrombotic thrombocytopenic purpura family

2014 ◽  
Vol 165 (1) ◽  
pp. 154-158 ◽  
Author(s):  
Benjamin Kim ◽  
Zachary A. Hing ◽  
Andrew Wu ◽  
Tal Schiller ◽  
Evi B. Struble ◽  
...  
Keyword(s):  
Differential Expression ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Single Nucleotide ◽  
Thrombocytopenic Purpura ◽  
Congenital Thrombotic Thrombocytopenic Purpura ◽  
Single Nucleotide Variations ◽  
Expression And Activity

Single-Nucleotide Variations Defining Previously Unreported ADAMTS13 Haplotypes Are Associated With Differential Expression and Activity Of The VWF-Cleaving Protease In a Salvadoran Congenital Thrombotic Thrombocytopenic Purpura Family

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2319-2319
Author(s):  
Benjamin Kim ◽  
Zachary A. Hing ◽  
Andrew Wu ◽  
Tal Schiller ◽  
Evi B. Struble ◽  
...  
Keyword(s):  
Steady State ◽  
Board Of Directors ◽  
Thrombotic Thrombocytopenic Purpura ◽  
Research Funding ◽  
Rt Pcr ◽  
Advisory Committees ◽  
Single Nucleotide ◽  
Thrombocytopenic Purpura ◽  
Congenital Thrombotic Thrombocytopenic Purpura ◽  
Single Nucleotide Variations

Abstract Background Although autosomal recessive hematologic disorders are individually rare and difficult to ascertain, studies involving one or more homozygous affected children and their unaffected heterozygous parents have led to expanded understanding of known and discovery of previously unknown processes. The son and daughter of two Salvadoran parents were diagnosed with congenital thrombotic thrombocytopenic purpura (cTTP) at 6 and 2 years of age, respectively, after presenting with fever, respiratory symptoms, hemolytic anemia, and thrombocytopenia and being found to have ADAMTS13 activities <1% without neutralizing IgG antibodies. They remain without long-term neurologic or renal sequelae following prophylactic infusions of fresh plasma (10 mL/kg every 2.5-weeks). The purpose of this study was to characterize and correlate single-nucleotide variations (SNVs) in each parent's, non-mutant ADAMTS13 allele with its mRNA and protein expression, activity, and enzyme kinetics. Methods Prior to a plasma infusion, blood samples were collected from the children and parents. Genomic DNA was isolated for polymerase chain reaction (PCR), and direct Sanger sequencing of all ADAMTS13 exons and flanking intronic segments was performed; all variants identified were confirmed by bidirectional sequencing of a second, independently generated amplicon. Total RNA was isolated and the steady-state level of ADAMTS13 mRNA was measured using a quantitative real-time PCR (q-RT-PCR)-based assay. ADAMTS13 was characterized enzymatically using the fluorogenic FRETS-VWF73 substrate and antigenically by ELISA. Results Both children were found to be homozygous and parents to be heterozygous for the previously described, cTTP-causing ADAMTS13 single-base-substitution mutation 20506C>T, a missense mutation that encodes cDNA-nucleotide 2518 (c.2518C>T) and ADAMTS13 residue 692 (692Arg>Cys [692R>C]) (Fig. A). As expected, the children's ADAMTS13 antigen and activity levels were undetectable, although notably, steady-state levels of the ADAMTS13 mRNA were >2.5-fold higher in the daughter than in the son. The re-sequenced regions of the ADAMTS13 loci segregating within this family contained 26 additional SNVs, seven of which were nonsynonymous (ns) including two previously unreported ns-SNVs: 27852C>T (c.3362C>T; 972Arg>Trp) and 33325G>A (c.3733G>A; 1096Arg>His) (Fig. A, left panel). The parents' genotypes differed at nine positions, including three ns-SNVs, creating two distinct, non-mutant haplotypes (designated I and III) at the gene, mRNA and protein levels. The q-RT-PCR assay revealed >4-fold higher steady-state mRNA levels in the father compared to the mother (p<0.001; Fig. B). Plasma ADAMTS13 activity and antigen levels were ∼2-fold greater in the father than in the mother (p=0.00164 and p=0.0633, respectively), but the specific activities of these structurally distinct ADAMTS13 proteins were notably almost identical (253.5 vs. 256.2 U/μg). Moreover, initial velocity kinetic analysis using the Michelis-Menten equation demonstrated that the Vmax of the father's ADAMTS13 was twice that of the mother's (1.4 vs. 0.7; p < 0.0001) while its affinity for substrate was one-third that of her ADAMTS13 (Km = 0.3 vs. 0.1; p = 0.0585). Discussion We capitalized on the fortuitous finding of children with complete homozygosity across ancestrally-related ADAMTS13 alleles harboring a null-type, loss-of-function mutation, as this enabled the substantially different levels of gene expression and function observed in the parents to be attributed to their two previously unreported, SNV-based, ADAMTS13 haplotypes. Additional investigation at the molecular, biochemical, cellular, and organismal levels will be necessary to determine which of the myriad potential individual SNV- and/or haplotype-based mechanisms are responsible for the observed parental differences in circulating ADAMTS13 antigen and activity. Disclosures: Kim: Haplomics, Inc.: Membership on an entity’s Board of Directors or advisory committees; Baxter: Honoraria. Marder:Baxter: Research Funding. Howard:Haplomics, Inc.: Equity Ownership, Membership on an entity’s Board of Directors or advisory committees; Baxter: Research Funding.

scholarly journals Characterization and treatment of congenital thrombotic thrombocytopenic purpura

Blood ◽  
2019 ◽  
Vol 133 (15) ◽  
pp. 1644-1651 ◽  
Author(s):  
Ferras Alwan ◽  
Chiara Vendramin ◽  
Ri Liesner ◽  
Amanda Clark ◽  
William Lester ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Age Of Onset ◽  
Organ Damage ◽  
Compound Heterozygous ◽  
Prophylactic Therapy ◽  
Thrombocytopenic Purpura ◽  
Stroke Incidence ◽  
End Organ Damage ◽  
Congenital Thrombotic Thrombocytopenic Purpura ◽  
Diagnosis Age

Abstract Congenital thrombotic thrombocytopenic purpura (cTTP) is an ultra-rare thrombomicroangiopathy caused by an inherited deficiency of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13). There are limited data on genotype-phenotype correlation; there is no consensus on treatment. We reviewed the largest cohort of cTTP cases, diagnosed in the United Kingdom, over the past 15 years. Seventy-three cases of cTTP were diagnosed, confirmed by genetic analysis. Ninety-three percent were alive at the time of review. Thirty-six percent had homozygous mutations; 64% had compound heterozygous mutations. Two presentation peaks were seen: childhood (median diagnosis age, 3.5 years) and adulthood, typically related to pregnancy (median diagnosis age, 31 years). Genetic mutations differed by age of onset with prespacer mutations more likely to be associated with childhood onset (P = .0011). Sixty-nine percent of adult presentations were associated with pregnancy. Fresh-frozen plasma (FFP) and intermediate purity factor VIII concentrate were used as treatment. Eighty-eight percent of patients with normal blood counts, but with headaches, lethargy, or abdominal pain, reported symptom resolution with prophylactic therapy. The most common currently used regimen of 3-weekly FFP proved insufficient for 70% of patients and weekly or fortnightly infusions were required. Stroke incidence was significantly reduced in patients receiving prophylactic therapy (2% vs 17%; P = .04). Long-term, there is a risk of end-organ damage, seen in 75% of patients with late diagnosis of cTTP. In conclusion, prespacer mutations are associated with earlier development of cTTP symptoms. Prophylactic ADAMTS13 replacement decreases the risk of end-organ damage such as ischemic stroke and resolved previously unrecognized symptoms in patients with nonovert disease.

scholarly journals Pregnancy onset congenital thrombotic thrombocytopenic purpura (Upshaw-Schulman syndrome) mimicking HELLP syndrome: a case report

2021 ◽  
Vol 29 (3) ◽  
pp. 270-273
Author(s):  
Başak Ergin ◽  
Berna Buse Kobal ◽  
Zeynep Yazıcı ◽  
Ali Hakan Kaya ◽  
Sezin Canbek ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Hellp Syndrome ◽  
Epigastric Pain ◽  
Novel Mutation ◽  
Adamts13 Activity ◽  
Thrombotic Microangiopathies ◽  
Thrombocytopenic Purpura ◽  
Uremic Syndrome ◽  
Congenital Thrombotic Thrombocytopenic Purpura ◽  
Low Platelet Count

Objective Thrombotic thrombocytopenic purpura is a thrombotic microangiopathic condition characterized by hemolytic anemia, thrombocytopenia, neurologic abnormalities, fever and renal dysfunction. Thrombotic microangiopathies such as preeclampsia and HELLP syndrome are pregnancy-specific, whereas others such as thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome are not. In this report, we present a case at which we identified a novel mutation which led to a significant reduction of ADAMTS13 activity. Case(s) A nulliparous pregnant woman of 32-year-old presenting with epigastric pain, hypertension and low platelet count was first suspected of HELLP syndrome, but was diagnosed with congenital TTP after delivery. Conclusion HELLP syndrome co-existed with undiagnosed TTP in this case. We strive to have sufficient awareness in order to distinguish these two pathologies from each other on an antenatal basis, because the causes of the managements are entirely different.

Congenital thrombotic thrombocytopenic purpura with novel mutations in three unrelated turkish children

2013 ◽  
Vol 61 (3) ◽  
pp. 558-561 ◽  
Author(s):  
Ayse Metin ◽  
Sule Unal ◽  
Fatma Gümrük ◽  
Roberta Palla ◽  
Andrea Cairo ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Novel Mutations ◽  
Thrombocytopenic Purpura ◽  
Turkish Children ◽  
Congenital Thrombotic Thrombocytopenic Purpura

Congenital thrombotic thrombocytopenic purpura (cTTP) with two novel mutations

2012 ◽  
Vol 59 (7) ◽  
pp. 1296-1298 ◽  
Author(s):  
Timothy D. Prestidge ◽  
Erica Rurali ◽  
Louis Wadsworth ◽  
John K. Wu ◽  
Jane C. Moore ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Novel Mutations ◽  
Thrombocytopenic Purpura ◽  
Congenital Thrombotic Thrombocytopenic Purpura

scholarly journals Multiplein silicotools predict phenotypic manifestations in congenital thrombotic thrombocytopenic purpura

2013 ◽  
Vol 160 (6) ◽  
pp. 825-837 ◽  
Author(s):  
Zachary A. Hing ◽  
Tal Schiller ◽  
Andrew Wu ◽  
Nobuko Hamasaki-Katagiri ◽  
Evi Budo Struble ◽  
...  
Keyword(s):  
Thrombotic Thrombocytopenic Purpura ◽  
Thrombocytopenic Purpura ◽  
Congenital Thrombotic Thrombocytopenic Purpura
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