Molecular analysis of FVIII gene in severe HA patients of Costa Rica.
Haemophilia A (HA) is X-chromosome linked bleeding disorders caused by deficiency of the coagulation factor VIII (FVIII). It is caused by FVIII gene intron 22 inversion (Inv22) in approximately 45% and by intron 1 inversion (Inv1) in 5% of the patients. Both inversions occur as a result of intrachromosomal recombination between homologous regions, in intron 1 or 22 and their extragenic copy located telomeric to the FVIII gene. The aim of this study was to analyze the presence of these mutations in 25 HA Costa Rican families.


METHODS
We studied 34 HA patients and 110 unrelated obligate members and possible carriers for the presence of Inv22or Inv1. Standard analyses of the factor VIII gene were used incl. Southern blot and long-range polymerase chain reaction for inversion analysis.


RESULTS
We found altered Inv22 restriction profiles in 21 patients and 37 carriers. It was found type 1 and type 2 of the inversion of Inv22. During the screening for Inv1 among the HA patient, who were Inv22 negative, we did not found this mutation.


CONCLUSIONS
Our data highlight the importance of the analysis of Inv22 for their association with development of inhibitors in the HA patients and we are continuous searching of Inv1 mutation. This knowledge represents a step for genetic counseling and prevention of the inhibitor development.
University of Costa Rica, Centre for Research in Hematology and Related Disorders (CIHATA),Costa Rica. lizbeth.salazar@gmail.com
L
L
Salazar-Sánchez
G
G
Jiménez-Cruz
M
M
Mendez
P
P
Chaverri
P
P
Alvarado
W
W
Schröder
K
K
Wulff
M
M
Sandoval
F H
FH
Herrmann
A
A
Pavlova
J
J
Oldenburg
D041321:Chromosomes, Human, X / Q000235:genetics; D003364:Costa Rica; D004247:DNA / Q000097:blood / Q000235:genetics / Q000302:isolation & purification; D005169:Factor VIII / Q000235:genetics*; D005260:Female; D006467:Hemophilia A / Q000097:blood / Q000235:genetics*; D006801:Humans; D007438:Introns / Q000235:genetics; D008297:Male; D010375:Pedigree; D016133:Polymerase Chain Reaction / Q000379:methods; D015183:Restriction Mapping; D012720:Severity of Illness Index
D005169:Factor VIII; D004247:DNA