1/146. Homozygous Cys542-->Arg substitution in GPIIIa in a Swiss patient with type I Glanzmann's thrombasthenia. Glanzmann's thrombasthenia (GT) arises from a qualitative or quantitative defect in the GPIIb-IIIa complex (integrin alphaIIbbeta3), the mediator of platelet aggregation. We describe a patient in whom clinical and laboratory findings typical of type I GT were found together with a second pathology involving neurological and other complications symptomatic of tuberous sclerosis. Analysis of platelet proteins by Western blotting revealed trace amounts of normally migrating GPIIb and equally small amounts of GPIIIa of slightly slower than normal migration. flow cytometry confirmed a much decreased binding to platelets of monoclonal antibodies to GPIIb, GPIIIa or GPIIb-IIIa, and an antibody to the alphav subunit also showed decreased binding. Nonradioactive PCR single-strand conformation polymorphism analysis followed by direct sequencing of PCR-amplified dna fragments showed a homozygous point mutation (T to C) at nucleotide 1722 of GPIIIa cDNA and which led to a Cys542-->Arg substitution in the GPIIIa protein. The mutation gave rise to a HinP1 I restriction site in exon 11 of the GPIIIa gene and allele-specific restriction enzyme analysis of family members confirmed that a single mutated allele was inherited from each parent. This amino acid substitution presumably changes the capacity for disulphide bond formation within the cysteine-rich core region of GPIIIa and its study will provide new information on GPIIb-IIIa and alphavbeta3 structure and biosynthesis. ( info) |
| Glanzmann's thrombasthenia is a rare autosomal recessive bleeding disorder resulting from a deficiency of glycoprotein IIb-IIIa complex in platelets. The deficient complex normally mediates platelet aggregation by binding adhesive proteins, which form bridges between activated cells. Despite normal platelet counts, morphology, prothrombin, and activated thromboplastin times, Glanzmann's thrombasthenia is characterized by a prolonged bleeding time and a severe hemorrhagic mucocutaneous diasthesis. pregnancy and delivery are rare in these patients and have been associated with a high risk of severe hemorrhage. We present an unusual case in which a primi-gravida patient with Glanzmann's thrombasthenia underwent an uneventful pregnancy and spontaneous vaginal delivery, following intrapartum intravenous administration of single-donor platelets. Subsequent late postpartum hemorrhage required intravenous transfusion of an additional unit of single-donor platelets. In addition, we review the literature pertaining to pregnancy and Glanzmann's thrombasthenia with an emphasis on intrapartum prophylactic management. ( info) |
3/146. A naturally occurring mutation near the amino terminus of alphaIIb defines a new region involved in ligand binding to alphaIIbbeta3. Decreased expression of functional alphaIIbbeta3 complexes on the platelet surface produces Glanzmann thrombasthenia. We have identified mutations of alphaIIb(P145) in 3 ethnically distinct families affected by Glanzmann thrombasthenia. Affected Mennonite and Dutch patients were homozygous and doubly heterozygous, respectively, for a P(145)A substitution, whereas a Chinese patient was doubly heterozygous for a P(145)L substitution. The mutations affect expression levels of surface alphaIIbbeta3 receptors on their platelets, which was confirmed by co-transfection of alphaIIb(P145A) and beta3 cDNA constructs in COS-1 cells. Each mutation also impaired the ability of alphaIIbbeta3 on affected platelets to interact with ligands. Moreover, when alphaIIb(P145A) and beta3 were stably coexpressed in Chinese hamster ovary cells, alphaIIbbeta3 was readily detected on the cell surface, but the cells were unable to adhere to immobilized fibrinogen or to bind soluble fluorescein isothiocyanate-fibrinogen after alphaIIbbeta3 activation by the activating monoclonal antibody PT25-2. Nonetheless, incubating affected platelets with the peptide LSARLAF, which binds to alphaIIb, induced PF4 secretion, indicating that the mutant alphaIIbbeta3 retained the ability to mediate outside-in signaling. These studies indicate that mutations involving alphaIIb(P145 )impair surface expression of alphaIIbbeta3 and that the alphaIIb(P145A) mutation abrogates ligand binding to the activated integrin. A comparative analysis of other alphaIIb mutations with a similar phenotype suggests that these mutations may cluster into a single region on the surface of the alphaIIb and may define a domain influencing ligand binding. (blood. 2000;95:180188) ( info) |
| Glanzmann's thrombasthenia is an autosomal recessive disorder characterized by a lack of platelet aggregation due to the absence of platelet glycoprotein IIb and IIIa. Usually, the disease leads to mild hemorrhage but sometimes bleeding is severe enough to be life-threatening. We report the case of a 16-year-old girl, presenting with very severe type 1 Glanzmann's thrombasthenia, successfully treated with an HLA-identical sibling bone marrow transplant (BMT). We also update the clinical and laboratory data of her brother, who had received a BMT 16 years ago for the same disease. In the light of these two cases and two others published in the literature, we discuss the indications for BMT from HLA-identical sibling donors in Glanzmann's thrombasthenia. Alloimmunization against the missing platelet GPIIb/IIIa complex and severity of bleeding episodes may constitute sufficient criteria for allogeneic BMT after careful assessment of the risk-benefit of such a procedure, although this remains exceptional in this disease. bone marrow transplantation (2000) 25, 327-330. ( info) |
5/146. Severe and relapsing upper gastrointestinal bleeding in a patient with Glanzmann's thrombasthenia. Glanzmann's thrombasthenia (GT) is a rare familial thrombocytic disease inherited as an autosomal recessive disorder that can induce hemorrhages due to a defect of platelet aggregation, resulting from the absence or reduced concentration of the membrane glycoproteic receptor binding the fibrinogen (integrin alpha(IIb)beta3). The gastrointestinal tract is the site of bleeding in only about 10% of cases but the related mortality is high (12.8%). Among the deaths due to hemorrhage, digestive bleeding causes 57.1%. According to reported data, the source of bleeding may be from preexisting gastroduodenal chronic and acute lesions. We report a case of severe and relapsing upper digestive bleeding in a woman with GT and coexisting thrombocytopenia (from HCV-related liver cirrhosis) and H. pylori-positive duodenal ulcer. ( info) |
6/146. Severe menorrhagia due to Glanzmann thrombasthenia treated with hydrothermal ablation. Glanzmann thrombasthenia is a rare platelet disorder inherited as an autosomal recessive trait. Abnormal uterine bleeding is a common problem in women with the disease. Medical management may not always be effective and further treatment may be necessary. Two women underwent endometrial ablation with a continuous-flow circulating hydrothermal ablator. After follow-up of 12 and 18 months, both women remained without abnormal uterine bleeding. ( info) |
7/146. Use of recombinant factor viia in 3 patients with inherited type I Glanzmann's thrombasthenia undergoing invasive procedures. The treatment of bleeds in Glanzmann's thrombasthenia is a challenging issue, especially when repeated platelet transfusions have induced anti-glycoprotein (GP) IIb-IIIa or anti-HLA allo-immunisation. In an attempt to find an alternative treatment regimen, we used recombinant factor viia (rFVIIa, NovoSeven, Novo Nordisk, denmark) as first-line therapy in 3 patients with Glanzmann's thrombasthenia and anti-GPIIb-IIIa iso-antibodies who were scheduled for invasive procedures. The administration of an initial bolus dose of rFVIIa (70-110 microg/kg) was immediately followed by continuous infusion at the rate of 9-30 microg/kg/h for 3-15 days. The treatment resulted in an excellent clinical efficacy and tolerance in 2 cases. In the third patient, whereas efficacy was excellent at the surgical site, pharyngonasal bleeds of traumatic origin persisted for 10 days, and a severe thromboembolic complication occurred 5 days after discontinuation of rFVIIa. Complementary studies are needed for patients with congenital platelet disorders in order to evaluate the safety and the potential therapeutic place of rFVIIa treatment. ( info) |
8/146. A case of lymphocytic infundibuloneurohypophysitis showing diabetes insipidus followed by anterior hypopituitarism associated with thrombasthenia. We report a case of a 42-year old male patient with diabetes insipidus followed by anterior hypopituitarism associated with thrombasthenia. The patient had been diagnosed with thrombasthenia since the age of 19. He was admitted and diagnosed as diabetes insipidus in 1995. Although T1-weighted image of magnetic resonance imaging (MRI) showed empty sella and partial pituitary stalk hypertrophy, the anterior pituitary functions were normal at that time. Three years later, he was re-admitted after an episode of general malaise and impotence in 1998. Endocrinological studies revealed adrenal insufficiency, hypothyroidism and hypogonadism. T1-weighted image of MRI demonstrated the thickening of pituitary stalk and neurohypophysis. Analysis of anti-pituitary antibodies by immunoblotting identified a major band at 61.5 kDa. The diabetes insipidus was controlled by desmopressin acetate and the shrinkage of pituitary stalk was seen after hormonal replacement therapy including glucocorticoid and thyroid hormone. We suggested that this case represented lymphocytic infundibuloneurohypophysitis, in which a chronic inflammatory process occurred in infundibulum and/or neurohypophysis and that hypopituitarism developed possibly due to damage to the pituitary portal vessels caused by a thickened pituitary stalk, although a pituitary biopsy was not done because of the risk of bleeding in thrombasthenia. The pituitary autoantibodies in sera from patients with hypopituitarism may be helpful to characterize the patient with lymphocytic hypophysitis. ( info) |
9/146. A 1063G-->A mutation in exon 12 of glycoprotein (GP)IIb associated with a thrombasthenic phenotype: mutation analysis of [324E]GPIIb. We report the molecular, genetic and functional analysis of a case of thrombasthenic phenotype. The proband showed absence of platelet glycoprotein (GP)IIb and very low content of GPIIIa, and both his parents showed a marked reduction in the levels of platelet GPIIb-IIIa. Single-stranded conformational polymorphism-polymerase chain reaction (SSCP-PCR) analysis and direct sequencing of PCR-amplified GPIIb exon-12 revealed the presence of a G-->A transition at position 1063 with the expected substitution of glutamate 324 with lysine (K). This mutation did not alter the level of GPIIb mRNA. Co-expression of normal or mutant [324K] GPIIb with normal human GPIIIa in Chinese hamster ovary (CHO) cells failed to show surface exposure of [324K]GPIIb-IIIa complexes. pulse-chase and immunoprecipitation analysis demonstrated that [324K]GPIIb cDNA was translated into proGPIIb, but neither mutant GPIIb heavy chain (GPIIbH) nor [324K]GPIIb-GPIIIa complexes were detected, suggesting that this mutation is the underlying molecular basis for the thrombasthenic phenotype. Mutation analysis demonstrated that 324E of GPIIb could be replaced by other negatively charged or polar amino acids (AAs) without impairing the surface expression of GPIIb-IIIa. However, substitution of 324E of GPIIb for a positively charged AA other than K prevented the expression of GPIIb-IIIa complexes. These observations suggest that a domain encompassing 324E of GPIIb is essential for heterodimerization with GPIIIa and its substitution for a positively charged residue precludes normal subunit association. ( info) |
10/146. Clinical spectrum of Glanzmann's thrombasthenia. Glanzmann's thrombasthenia is a well defined inherited disorder of platelet function characterized by qualitative and qualitative defect in cytoadhesive membrane protein, glycoprotein IIb-IIIa (the platelet fibrinogen receptor). From January 1990 to October, 1999, five patients who presented with mucocutaneous bleeding were detected to have Glanzmann's thrombasthenia. Clinical and laboratory spectrum of this rare disorder was studied which revealed heterogeneity of disease with respect to nature and severity of bleeding unpredictable by laboratory findings. ( info) |