Endogenous Thrombin Potential (ETP) in Patients with Hereditary Antithrombin (AT) Deficiency or Carriers of the Prothrombin (PT) 20210A Gene Mutation.

Abstract Hereditary thrombophilias are associated with an increased risk of venous thromboembolism (VTE) but the magnitude of the risk is not the same: very high in AT deficiency type I or type II RS (Reactive Site) or PE (Pleiotropic Effect), moderate or nul in HBS (Heparin Binding Site) type AT deficiency. According to Butenas S, van’t Veer C, Mann KG. (Blood1999; 94: 2169–78), the dominant factors influencing thrombin generation in a synthetic ‘plasma’ system are prothrombin and AT. Determination of the Endogenous Thrombin Potential (ETP) has been proposed as a valuable tool to detect thrombin generation and hypercoagulability. Aim of the study: Evaluation of ETP in AT deficient patients with different types of deficiency (type I or II) and in carriers of the prothrombin (PT) 20210A gene mutation. Methods The study concerns 35 AT deficient patients: type I or II RS or PE (n=28) or type II HBS (n=7) and 38 carriers of the PT 20210A mutation (24 heterozygous, 14 homozygous). Patients had no antithrombotic or hormonal treatment and women were not pregnant. They have been compared to 59 healthy subjects. ETP was measured in citrated frozen platelet poor plasma by Hemker method initiated by addition of diluted recombinant tissue factor and phospholipids. The following parameters were recorded: ETP (nM/min) as total Thrombin Generation, Peak (nM) as amount of thrombin generated, Start-to-Tail (ST) minus Time-to-Peak (TTP) (min) as an index of thrombin inhibition. Complete thrombophilia screening was also performed. Results: ETP is significantly increased in type I or type II RS or PE AT deficient patients and in patients with heterozygous or homozygous PT 20210A mutations as compared to controls (p<.001), but less increased in HBS type II AT deficiency. n ETP (nM/min) Peak (nM) ST-TTP (min) Controls 59 1484+/−309 296+/−45 15.2+/−1.9 AT HBS 7 1734+/−172 341+/−43 15.2+/−1.1 PT heterozygous 24 2221+/−391 373+/−57 18.3+/−2.7 PT homozygous 14 2606+/−474 385+/−59 21.4+/−3.8 AT I or II RS or PE 28 2655+/−391 359+/−41 25.4+/−5.1 These results demonstrate that ETP, marker of hypercoagulability, is gradually increased in patients with HBS type II AT deficiency, heterozygous and homozygous PT 20210A mutation and in types of AT deficiency other than HBS. The parameter ST-TTP is normal in HBS type II AT deficiency. It reflects the speed of inhibition of the thrombin generated, depending on the amount of thrombin generated and the degree of inhibition. Conclusion: Our findings suggest that ETP might be useful as a first line test for thrombophilia screening to detect hypercoagulability and ST-TTP as a marker of thrombin inhibition. Results of this large series of patients with AT deficiency and homozygous PT 20210A mutation should be compared with the magnitude of the risk of VTE in different thrombophilias, including patients with factor V Leiden mutation or combined thrombophilias.

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Impact of the type of SERPINC1 mutation and subtype of antithrombin deficiency on the thrombotic phenotype in hereditary antithrombin deficiency

Thrombosis and Haemostasis ◽

10.1160/th13-05-0402 ◽

2014 ◽

Vol 111 (02) ◽

pp. 249-257 ◽

Cited By ~ 22

Author(s):

Anna Pavlova ◽

Christof Geisen ◽

Michael Spannagl ◽

Frauke Bergmann ◽

Manuela Krause ◽

...

Keyword(s):

Lower Risk ◽

Type I ◽

Missense Mutations ◽

Type Ii ◽

Antithrombin Deficiency ◽

Vein Thrombosis ◽

At Deficiency ◽

Deficiency Type ◽

Deep Vein ◽

The Impact

SummaryMutations in the antithrombin (AT) gene can impair the capacity of AT to bind heparin (AT deficiency type IIHBS), its target proteases such as thrombin (type IIRS), or both (type IIPE). Type II AT deficiencies are almost exclusively caused by missense mutations, whereas type I AT deficiency can originate from missense or null mutations. In a retrospective cohort study, we investigated the impact of the type of mutation and type of AT deficiency on the manifestation of thromboembolic events in 377 patients with hereditary AT deficiencies (133 from our own cohort, 244 reported in the literature). Carriers of missense mutations showed a lower risk of venous thromboembolism (VTE) than those of null mutations (adjusted hazard ratio [HR] 0.39, 95% confidence interval [CI] 0.27–0.58, p<0.001), and the risk of VTE was significantly decreased among patients with type IIHBS AT deficiency compared to patients with other types of AT deficiency (HR 0.23, 95%CI 0.13–0.41, p<0.001). The risk of pulmonary embolism complicating deep-vein thrombosis was lower in all type II AT deficiencies compared to type I AT deficiency (relative risk 0.69, 95%CI 0.56–0.84). By contrast, the risk of arterial thromboembolism tended to be higher in carriers of missense mutations than in those with null mutations (HR 6.08-fold, 95%CI 0.74–49.81, p=0.093) and was 5.9-fold increased (95%CI 1.22–28.62, p=0.028) in type IIHBS versus other types of AT deficiency. Our data indicate that the type of inherited AT defect modulates not only the risk of thromboembolism but also the localisation and encourage further studies to unravel this phenomenon.

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The Molecular Basis of Antithrombin Deficiency in Belgian and Dutch Families

Thrombosis and Haemostasis ◽

10.1055/s-0037-1615215 ◽

1998 ◽

Vol 80 (09) ◽

pp. 376-381 ◽

Cited By ~ 6

Author(s):

W. Lissens ◽

S. Seneca ◽

P. Capel ◽

B. Chatelain ◽

P. Meeus ◽

...

Keyword(s):

Molecular Basis ◽

Gene Deletion ◽

Direct Sequencing ◽

Genetic Defect ◽

Polymorphism Analysis ◽

Type I ◽

Type Ii ◽

Antithrombin Deficiency ◽

Venous Thromboembolic Events ◽

At Deficiency

SummaryThe molecular basis of hereditary antithrombin (AT) deficiency has been investigated in ten Belgian and three Dutch unrelated kindreds. Eleven of these families had a quantitative or type I AT deficiency, with a history of major venous thromboembolic events in different affected members. In the other two families a qualitative or type II AT deficiency was occasionally diagnosed.DNA studies of the AT gene were performed, using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) analysis, followed by direct sequencing of the seven exons and intronexon junction regions. Six novel point mutations were identified: four missense, one nonsense mutation and a single nucleotide deletion near the reactive site, causing a frameshift with premature translation termination. In two kindreds the underlying genetic defect was caused by a whole gene deletion, known as a rare cause of AT deficiency. In these cases, Southern blot and polymorphism analysis of different parts of the AT gene proved useful for diagnosis. In another kindred a partial gene deletion spanning 698 basepairs could precisely be determined to a part of intron 3B and exon 4. In two type I and in both type II AT deficient families a previously reported mutation was identified. In all cases, the affected individuals were heterozygous for the genetic defect.

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Molecular analysis and genotype-phenotype correlation in patients with antithrombin deficiency from Southern Italy

Thrombosis and Haemostasis ◽

10.1160/th11-09-0671 ◽

2012 ◽

Vol 107 (04) ◽

pp. 673-680 ◽

Cited By ~ 11

Author(s):

Giuseppe Castaldo ◽

Anna Cerbone ◽

Anna Guida ◽

Igor Tandurella ◽

Rosaria Ingino ◽

...

Keyword(s):

Molecular Analysis ◽

Southern Italy ◽

Stop Codon ◽

Type I ◽

Missense Mutations ◽

Type Ii ◽

Clinical Expression ◽

Antithrombin Deficiency ◽

At Deficiency ◽

Molecular Bases

SummaryWe sequenced the SERPINC1 gene in 26 patients (11 males) with antithrombin (AT) deficiency (22 type I, 4 type II), belonging to 18 unrelated families from Southern Italy. Heterozygous mutations were identified in 15/18 (83.3%) families. Of them, eight were novel mutations, each being identified in one family. Seven clearly cause impaired protein synthesis (four frameshift, one non-stop, one splicing and one 21bp deletion). One, present in a single patient, is a missense mutation thought to be causative because: a) it is absent in 100 chromosomes from controls; b) it involves a highly conserved amino acid, whose change is predicted to impair AT activity; c) no other mutation is present in the propositus. Severe mutations (i.e. nonsense, frameshift, deletions) were invariably identified in type I patients. In type II patients, 3/4 were missense mutations; the fourth leads to a 19 nucleotides shift in the stop codon. In addition to the type of mutation, the co-existence of other predisposing factors in most patients helps explain the severity of the present type I cases (age at first event, recurrence during prophylaxis). In the five families in which there was more than one member affected, the same genotype and a concordant clinical expression of the disease were found. We conclude that the molecular bases of AT deficiency in Southern Italy are different as compared to other geographic areas, and that molecular analysis and the study of the effect of the mutation may help predict the clinical expression of the disease.

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Molecular genetic study in two patients with congenital hypoaldosteronism (types I and II) in relation to previously published hormonal studies

Acta Endocrinologica ◽

10.1530/eje.0.1390096 ◽

1998 ◽

pp. 96-100 ◽

Cited By ~ 14

Author(s):

M Peter ◽

K Bunger ◽

SL Drop ◽

WG Sippell

Keyword(s):

Genetic Study ◽

Stop Codon ◽

Molecular Genetic ◽

Premature Stop Codon ◽

Type I ◽

Type Ii ◽

Loss Of Function ◽

Molecular Genetic Study ◽

Base Exchange ◽

Deficiency Type

We performed a molecular genetic study in two patients with congenital hypoaldosteronism. An original study of these patients was published in this Journal in 1982. Both index cases, a girl (patient 1) and a boy (patient 2). presented with salt-wasting and failure to thrive in the neonatal period. Parents of patient 1 were not related, whereas the parents of patient 2 were cousins. Endocrine studies had shown a defect in 18-oxidation of 18-OH-corticosterone in patient 1 and a defect in the 18-hydroxylation of corticosterone in patient 2. Plasma aldosterone was decreased in both patients, whereas 18-OH-corticosterone was elevated in patient 1 and decreased in patient 2. Plasma corticosterone and 11-deoxycorticosterone were elevated in both patients, whereas cortisol and its precursors were in the normal range. According to the nomenclature proposed by Ulick, the defects are termed corticosterone methyl oxidase (CMO) deficiency type II in patient 1, and type I in patient 2 respectively. Genetic defects in the gene CYP11B2 encoding aldosterone synthase have been described in a few cases. In patient 1, we identified only one heterozygous amino acid substitution (V386A) in exon 7, which has no deleterious effect on the enzyme activity. In patient 2 and his older brother, we identified a homozygous single base exchange (G to T) in codon 255 (GAG), causing a premature stop codon E255X (TAG). The mutant enzyme has lost the five terminal exons containing the haem binding site, and is thus a loss of function enzyme. This is only the second report of a patient with CMO deficiency type II without a mutation in the exons and exon-intron boundaries, whereas the biochemical phenotype of the two brothers with CMO deficiency type I can be explained by the patient's genotype.

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A Novel GH-1 Gene Mutation (GH-P59L) Causes Partial GH Deficiency Type II Combined with Bioinactive GH Syndrome

10.1210/endo-meetings.2011.part2.p38.p2-386 ◽

2011 ◽

pp. P2-386-P2-386

Author(s):

Vibor Petkovic ◽

Andree Eble ◽

Amit V Pandey ◽

Marta Betta ◽

Patrizia Mella ◽

...

Keyword(s):

Gene Mutation ◽

Gh Deficiency ◽

Type Ii ◽

Deficiency Type

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The effect of ACTH stimulation on plasma steroids in two patients with congenital hypoaldosteronism and in their relatives

Acta Endocrinologica ◽

10.1530/acta.0.0990245 ◽

1982 ◽

Vol 99 (2) ◽

pp. 245-250 ◽

Cited By ~ 6

Author(s):

S. L. S. Drop ◽

I. M. E. Frohn-Mulder ◽

H. K. A. Visser ◽

W. G. Sippell ◽

H. G. Dörr ◽

...

Keyword(s):

Plasma Levels ◽

Zona Glomerulosa ◽

The Other ◽

Type I ◽

Type Ii ◽

Acth Stimulation ◽

Oxidase Deficiency ◽

Before And After ◽

Plasma Steroids ◽

Deficiency Type

Abstract. In two children with isolated congential hyperreninaemic hypoaldosteronism, as well as in their relatives, plasma levels of aldosterone (Aldo), corticosterone (B), deoxycorticosterone (DOC), 18-OH-B and 18-OH-DOC were measured before and after an iv bolus of 0.25 mg Synacthen® (Ciba). A corticosterone methyl oxidase deficiency type II was demonstrated in one child. Her normoreninaemic parents (no consanguinity) had plasma values consistent with heterozygosity. The results in the other child and one asymptomatic sib were compatible with a partial corticosterone methyl oxidase deficiency type I. His parents were consanguine but had normal Aldo levels. Overnight dexamethasone administration did not suppress any of the steroids measured except cortisol, suggesting synthesis of these steroids by the zona glomerulosa.

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