RESUMO
Haemophilia B is an X-linked recessive bleeding disorder caused by mutations in the factor IX gene with an incidence of 1:25000-30000. Usually female carriers are clinically normal, and severe phenotypic expression of the disease in females is extremely rare. In this report we describe a girl with a clinically severe course of haemophilia B who had no signs of Turner syndrome or any other dysmorphic features. Cytogenetic and molecular studies in the patient and her parents showed a de novo translocation 46,X,t(X;15)(q27.1;p11.2) in the patient, indicating a possible break near the factor IX gene. The structurally normal X chromosome was late replicating and inactivated in all metaphases as shown by high-resolution R-banding. By fluorescence in situ hybridization (FISH) with YAC and cosmid probes we could further characterize the breakpoint region on the X chromosome and the involvement of the factor IX gene.
Assuntos
Cromossomos Humanos Par 15/genética , Hemofilia B/genética , Translocação Genética , Cromossomo X/genética , Adulto , Coagulação Sanguínea , Southern Blotting , Mecanismo Genético de Compensação de Dose , Éxons , Fator IX/genética , Feminino , Hemofilia B/sangue , Humanos , Hibridização in Situ Fluorescente , LinhagemRESUMO
The results of bleedings treatment in 11 children with haemophilia A and factor VIII (f. VIII) inhibitor was presented. Concentrates of human and porcine f. VIII and activated prothrombin complex concentrate were used in the treatment. The method of treatment depended on the level of human and porcine f. VIII inhibitors. In patients with level of human f. VIII inhibitor lower than 10 jB/ml the concentrates of human f. VIII in doses 2-3 times higher than usually used in haemophiliacs without inhibitor were successful. When inhibitor level was higher than 10 jB/ml, but low cross-reactivity of porcine f. VIII was stated, concentrates of porcine f. VIII were used with good result. In children with high level of antibody against human and porcine f. VIII, the best results were achieved using activated prothrombin complex concentrates.
