Prevalence of activated protein C resistance (Factor V Leiden) in Lagos, Nigeria.
OBJECTIVE
Hereditary resistance to activated Protein C (Factor V Leiden) is the commonest genetic defect known to confer a predisposition to thrombosis. This study aims to determine the prevalence of activated protein C resistance (APCr) in Lagos, and to determine if any association exists between APCr and ABO, Rhesus blood types, and hemoglobin phenotypes.


METHODS
A functional APCr test was conducted on healthy adult volunteers to get a Factor-V-related activated protein C ratio (APC-V ratio). APCr due to Factor V mutation was indicated when the APC-V ratio is below a cut-off value that was determined by calibration. Subjects' hemoglobin, red cell ABO, and Rhesus phenotypes were determined by standard methods.


RESULTS
Six (2%) of 297 participants with normal baseline coagulation screening tests had functional resistance to activated protein C (APC-V ratio < 2). None of the six subjects with APCr had history of venous thromboembolism. One of the six subjects was a female but the male sex did not demonstrate a risk of inheritance of APCr (P = 0.39). Four (67%) of the six subjects with APCr were non-O blood group. Whereas only two (0.9%) of 226 non-A subjects (blood groups 0 and B) had APCr, 4 (6%) of 71 subjects with A gene (blood groups A and AB) had APCr. The inheritance of A gene appears to constitute a risk to inheritance of APCr (P = 0.03). No association was demonstrable between APCr and hemoglobin phenotypes.


CONCLUSIONS
Only 2% of the studied population had resistance to APC. The inheritance of blood group A may be a predisposition to APCr.
Department of Haematology and Blood transfusion, Faculty of Clinical Sciences, College of Medicine, University of Lagos, Nigeria. titilopeadeyemo2002@yahoo.com.uk
T A
TA
Adeyemo
A
A
Adediran
A A
AA
Akinbami
A S
AS
Akanmu
D000017:ABO Blood-Group System / Q000097:blood*; D020016:Activated Protein C Resistance / Q000453:epidemiology* / Q000235:genetics; D000293:Adolescent; D000328:Adult; D005165:Factor V; D005260:Female; D006454:Hemoglobins; D006801:Humans; D008297:Male; D008875:Middle Aged; D009549:Nigeria / Q000453:epidemiology; D010641:Phenotype; D015995:Prevalence; D012204:Rh-Hr Blood-Group System / Q000097:blood*; D055815:Young Adult
D000017:ABO Blood-Group System; D006454:Hemoglobins; D012204:Rh-Hr Blood-Group System; C095381:factor V Leiden; D005165:Factor V