Haemostatic patterns and bleeding scores of a genetically characterised Italian family with combined haemophilia A and type 1 von Willebrand disease.

: We report on the coinheritance of mild haemophilia A and type 1 von Willebrand disease (VWD) in a genetically characterized Italian family. The proband is a 56-year-old man carrying both the c.2167G>A mutation in the factor VIII (FVIII) gene (responsible for p.A723T substitution) and the c.4751A>G mutation (p.Y1584C) in the von Willebrand factor (VWF) gene. His FVIII and VWF levels were 9.8 and 43.2 IU/dl, respectively. His bleeding symptoms included mucocutaneous bleeding, haemarthrosis, and muscle haematomas. Using the bleeding assessment tool, a questionnaire currently employed in diagnosing VWD, the patient had a bleeding score of 27 as compared with the 10.2 ±â€Š3.4 found in patients with mild-to-moderate haemophilia A, and 0-3 in normal men. One of the proband's two daughters (both obligate carriers of haemophilia A) also harboured the VWF p.Y1584C mutation. Her FVIII and VWF levels were 45.9 and 54 IU/dl, respectively, and her bleeding score was slightly higher than normal for women (6 vs. 0-5). The other daughter had a normal bleeding score, and so did the proband's father (with type 1 VWD) and mother (haemophilia A carrier). Discrepancies between haemostatic patterns and bleeding symptoms in cases of haemophilia A, as seen in our patient, suggest the need to search for other coagulation defects, especially involving VWF, which is the carrier of FVIII. Although the presence of a VWF mutation significantly exacerbates the haemorrhagic complications in patients with mild haemophilia A, it has only mild effects on haemophilia A carriers.

Higher and lower active circulating VWF levels: different facets of von Willebrand disease.

Most circulating von Willebrand factor (VWF) is normally inactive and incapable of binding platelets, but numerous disorders may modify the proportion of active VWF. We explored active VWF levels in patients with von Willebrand disease (VWD) whose VWF had a higher affinity for platelet glycoprotein (GP)Ib, but different susceptibilities to ADAMTS13 and multimer patterns (9 patients lacking large multimers, 10 with a normal pattern); 12 patients with VWF C2362F and R1819_C1948delinsS mutations, which make VWF resistant to ADAMTS13 were also studied. Type 2B patients with abnormal or normal multimers had significantly more active VWF (3·33 ± 1·6 and 3·74 ± 0·74, respectively; normal 0·99 ± 0·23). The type of VWF mutation influenced VWF activation: V1316M was associated with the highest levels in patients with abnormal multimers, and R1341W in those with normal multimers. Pregnancy induced gradually rising active VWF levels and declining platelet counts in one type 2B VWD patient without large multimers. Active VWF levels dropped significantly in patients homozygous for the C2362F mutation or heterozygous for R1819_C1948delinsS mutations (0·2 ± 0·03 and 0·23 ± 0·1, respectively), and less in cases heterozygous for the VWF C2362F mutation (0·55 ± 0·17). We demonstrate that VWF may be more or less activated, with or without any direct involvement of the A1 domain, and regardless of ADAMTS13.

The p.R1819_C1948delinsS mutation makes von Willebrand factor ADAMTS13-resistant and reduces its collagen-binding capacity.

This report concerns abnormal ADAMTS13 (a disintegrin and metalloprotease with a thrombospondin type 1 motif, member 13) and collagen interactions coinciding with the p.R1819_C1948delinsS von Willebrand factor (VWF) mutation associated with the deletion of the C-terminus of the A3 domain (amino acids 1819-1947) in a patient with a history of bleeding. The von Willebrand disease (VWD) phenotype of the patient featured low plasma and platelet VWF, multimers with smears extending over the highest normal oligomers in plasma, but not platelets, and an impaired collagen-binding capacity. In vitro full-length p.R1819_C1948delinsS VWF expression showed impaired VWF release, increased cellular content with normally-multimerized VWF and impaired collagen binding. The recombinant p.R1819_C1948delinsS VWF fragment, extending from domains A2 to B3 (p.R1819_C1948delinsS A2-B3 VWF), was completely resistant to proteolysis by ADAMTS13 in the presence of 1·5 mol/l urea, unlike its normal counterpart. The defect stems from impaired ADAMTS13 binding to p.R1819_C1948delinsS A2-B3, analysed under static conditions. Partial deletion of the C-terminus of the A3 domain thus makes VWF resistant to ADAMTS13, interfering with ADAMTS13 binding to VWF, and impairing the collagen-binding capacity of VWF. The p.R1819_C1948delinsS mutation has both haemorrhagic features (defective collagen binding, reduced VWF levels) and prothrombotic (ADAMTS13 resistance) features, and the latter probably mitigate the patient's bleeding symptoms.

Hypercortisolism and pregnancy upregulate von Willebrand factor through different mechanisms: report on a pregnant patient with Cushing's syndrome.

Von Willebrand factor (VWF) is reportedly increased in pregnancy and Cushing's syndrome, inducing a hypercoagulable state. In Cushing's syndrome, VWF gene promoter polymorphisms modulate cortisol-dependent VWF upregulation, haplotype 1 (GCAG) and short GT-repeats (GT)(S) being the susceptible, and haplotype 2 (CTGA) and long GT-repeats (GT)(L) the protective pattern. We report on a Cushing's syndrome patient who became pregnant under hypercortisolism, in whom we monitored the evolution of her hypercoagulable state. During the active phase of Cushing's syndrome, the patient's VWF and factor VIII concentrations were normal, despite high urinary-free cortisol levels consistent with the presence of haplotype 2 and (GT)(L) alleles in the VWF gene promoter. VWF and factor VIII increased significantly and progressively after she became pregnant and peaked just before delivery, returning to normal 5 months later, while her hypercortisolism persisted. Our data indicate that two different mechanisms upregulate VWF under hypercortisolism and pregnancy, the latter being independent of the VWF promoter haplotypes sensitive to cortisol excess.

Microsatellite (GT)(n) is part of the von Willebrand factor (VWF) promoter region that influences the glucocorticoid-induced increase in VWF in Cushing's syndrome.

INTRODUCTION: The cortisol-induced increase in von Willebrand factor (VWF) in Cushing's syndrome (CS) seems to depend on single nucleotide polymorphisms (SNPs) of the VWF promoter, haplotype 1 (-3268G/-2709C/-2661A/-2527G) being the susceptible pattern. MATERIALS AND METHODS: This study focused on a new variable region of the VWF promoter, the -2144(GT)(n) locus, to establish whether different GT-repeat lengths are also involved in modulating the cortisol-induced increase in VWF. Sixty-nine CS patients were investigated, divided into groups A (high VWF) and B (normal VWF). RESULTS: Analysing the (GT)(n) locus revealed a similar allele distribution in CS patients and normal subjects, (GT)(n) variants ranging from 15 to 24 repeats and (GT)(19) and (GT)(21) being the two most represented. However, when groups A and B were analysed separately, a different allele distribution was observed: short GT-repeats (15-19, GT(S)) were more frequent in group A, long GT-repeats (20-24, GT(L)) in group B (p=0.01). About genotype distributions, (GT)(S)/(GT)(S) was higher in group A and rare in group B (22.5% and 3.4%, respectively), whereas (GT)(L)/(GT)(L) was higher in group B than in group A (55.2%, 27.5%) (p=0.021). Odds-ratio analysis revealed a risk of a cortisol-dependent increase in VWF three times higher for alleles (GT)(S) than for (GT)(L), and 13-fold for genotype (GT)(S)/(GT)(S) respect to (GT)(L)/(GT)(L). CONCLUSIONS: In conclusion, not only the SNPs haplotypes in the VWF gene promoter, but also the variable-length (GT)(n) locus predict the risk of developing high VWF levels under conditions of glucocorticoid excess; the combination of (GT)(S) and haplotype 1 represents the susceptible pattern.