Angiotensin converting enzyme insertion/deletion polymorphisms in vasovagal syncope.
Recent studies suggest vasovagal syncope (VVS) has a significant heritable component (crude estimate sibling relative risk (lambda(s)): 1080) indicating that at least some forms of VVS may have a genetic cause. Here we present the first study examining a potential genetic abnormality in VVS.


METHODS
DNA was collected from consecutive patients attending our unit with head up tilt confirmed VVS (n=165). One hundred and fourteen affected and unaffected first-degree relatives of those with a definitive diagnosis of VVS and positive family history also provided DNA.


RESULTS
DNA from 165 VVS index cases was genotyped for the ACE insertion/deletion polymorphism. Mean+/-SD age of cases was 56+/-19 years (103 (62%) females). There was no significant difference in distribution of ACE insertion or deletion gene frequencies in cases compared with a large (>6000 subjects) national control population. No preferential transmission of alleles in families was identified using tests of association (P=0.1789)


CONCLUSIONS
We have shown using both a case control and a small family based association study that polymorphisms of ACE alone are not associated with increased risk of VVS. Further studies are planned to clarify the genotype/phenotype relationship in VVS and examine other candidate genes.
Newton
Julia L
JL
Cardiovascular Investigation Unit (Institute for Ageing and Health), Care of the Elderly Offices, Royal Victoria Infirmary, University of Newcastle, Newcastle NE1 4LP, United Kingdom. julianewton@blueyonder.co.uk
Donaldson
Peter
P
Parry
Steve
S
Kenny
Rose Anne
RA
Smith
Jennifer
J
Gibson
Alison M
AM
Morris
Christopher
C
D016022:Case-Control Studies; D004251:DNA Transposable Elements / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D006801:Humans; D008297:Male; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000235:genetics*; D011110:Polymorphism, Genetic; D019462:Syncope, Vasovagal / Q000235:genetics*
D004251:DNA Transposable Elements; D007703:Peptidyl-Dipeptidase A