The Sebastian platelet syndrome. Report of the first native Saudi Arabian patient

Fechtner's syndrome: considerations of anesthetic management

IMPLICATIONS

Fechtner's syndrome is a rare form of macrothrombocytopenia (potentially associated with other hemostatic deficiencies, e.g., von Willebrand's disease and protein Z deficiency), which can exacerbate the risk of uncontrollable bleeding during surgery. We describe the management of a patient with Fechtner's syndrome involving desmopressin, prednisone, and platelets, which produced safe and effective results during cochlear implant surgery.

The gene for May-Hegglin anomaly localizes to a <1-Mb region on chromosome 22q12.3-13.1

The May-Hegglin anomaly (MHA) is an autosomal dominant platelet disorder of unknown etiology. It is characterized by thrombocytopenia, giant platelets, and leukocyte inclusion bodies, and affected heterozygotes are predisposed to bleeding episodes. The MHA gene has recently been localized, by means of linkage analysis, to a 13.6-cM region on chromosome 22, and the complete chromosome 22 sequence has been reported. We recently performed a genome scan for the MHA gene in 29 members of a large, multigenerational Italian family, and we now confirm that the MHA locus is on chromosome 22q12. 3-13.1. The maximal two-point LOD score of 4.50 was achieved with the use of marker D22S283, at a recombination fraction of.05. Haplotype analysis narrowed the MHA critical region to 6.6 cM between markers D22S683 and D22S1177. It is of note that the chromosome 22 sequence allowed all markers to be ordered correctly, identified all the candidate genes and predicted genes, and specifically determined the physical size of the MHA region to be 0. 7 Mb. These results significantly narrow the region in which the MHA gene is located, and they represent the first use of chromosome 22 data to positionally clone a disease gene.

Inherited giant platelet disorders. Classification and literature review

Inherited giant platelet disorders are extremely rare. The aim of this article is to review the clinical and laboratory features of this heterogeneous group and to arrive at a working classification. We conducted our literature search using the National Library of Medicine database. A total of 12 clinical entities were described. We classified them into 4 groups depending on the clinical and structural abnormalities. The pathophysiology of these disorders is largely unknown, and more research is needed, particularly in the light of recent advances in laboratory medicine. This review may provide a valuable reference for clinicians and may form a basis for future classification and research.

Sebastian syndrome: case report and review of the literature

Macrothrombocytopenias (MTCP) are a heterogeneous group of disorders associated with thrombocytopenia and giant platelets, and may include other clinical or laboratory findings such as hereditary nephritis, sensorineural deafness, leukocyte inclusions, and cataracts. Patients with MTCP may have mild to moderate bleeding symptoms or be completely asymptomatic. The most recently described MTCP is the Sebastian syndrome (SS), which consists of thrombocytopenia with giant platelets and leukocyte inclusions. Only three previous reports about this syndrome have been published. Herein, we report the first African-American family with SS. The propositus is a 4-week-old male born to a mother carrying the diagnosis of chronic idiopathic thrombocytopenia purpura (ITP). His 4-year-old brother also has thrombocytopenia. There is no history of bleeding symptoms in any of the family members. The diagnosis was established by demonstrating thrombocytopenia with giant platelets and leukocyte inclusions on both peripheral smear and by electron microscopy. This report illustrates the importance of obtaining a family history when evaluating thrombocytopenia with special emphasis on a history of thrombocytopenia, renal disease, deafness, and cataracts. It is important to differentiate between MTCP and chronic ITP to avoid the unnecessary diagnostic studies, and, more critically, unneeded and potentially harmful therapy.

Giant platelets with abnormal surface glycoproteins: a new familial disorder associated with mitral valve insufficiency

PURPOSE

To study the platelets from a family with a new form of inherited giant platelet disorder.

PATIENTS AND METHODS

Two siblings exhibited a hemorrhagic disorder characterized by moderate thrombocytopenia, giant platelets, and markedly prolonged bleeding time. The parents had no discernible platelet defect. Both children also developed mitral regurgitation requiring medication, and one underwent surgical replacement at the age of 3 years.

RESULTS

The mean platelet size was greater than 20 microm3. Direct measurements of the two major axes of each of 12 platelets on electron micrographs revealed a range of 2x4 to 4x6 microm. Electron microscopy did not demonstrate any abnormality of granule content. The platelets agglutinated normally with ristocetin and aggregated normally with collagen. However, the aggregation was slightly slower than normal with ADP, epinephrine, and Na arachidonate. Two-dimensional unreduced versus reduced SDS-polyacrylamide gel electrophoresis of surface radioiodinated platelet glycoproteins revealed absence of proteins Ia, Ic, and IIa in both affected children, whereas GP Ib, IIb, and IIIa appeared normal. The 2D gels of platelet glycoproteins from both parents were identical to controls. Western blots demonstrated that GP Ic, Ic', Ib, and Ia/IIa were present.

CONCLUSIONS

This disorder represents a new syndrome of thrombocytopenia with giant platelets distinct from Bernard-Soulier, Montreal giant platelets, Swiss cheese platelets, May-Hegglin anomaly, and other previously described syndromes.