A de novo translocation 46,X,t(X;15) causing haemophilia B in a girl: a case report.
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.
Schröder
W
W
Ernst-Moritz-Arndt University, Institute for Human Genetics, Greifswald, Germany.
Poetsch
M
M
Gazda
H
H
Werner
W
W
Reichelt
T
T
Knoll
W
W
Rokicka-Milewska
R
R
Zieleniewska
B
B
Herrmann
F H
FH
D000328:Adult; D001777:Blood Coagulation; D015139:Blotting, Southern; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics*; D004303:Dosage Compensation, Genetic; D005091:Exons; D005164:Factor IX / Q000235:genetics; D005260:Female; D002836:Hemophilia B / Q000097:blood / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D010375:Pedigree; D014178:Translocation, Genetic; D014960:X Chromosome / Q000235:genetics*
D005164:Factor IX