Endothelial nitric oxide synthase T-786C single nucleotide polymorphism: a putative genetic marker differentiating small versus large ruptured intracranial aneurysms.
OBJECTIVE
Anecdotal evidence exists for at least 2 subpopulations of intracranial saccular aneurysms, namely, those that may form rapidly and rupture when small versus those that enlarge slowly and may rupture particularly when > or =10 mm in diameter. We sought to determine whether the endothelial nitric oxide synthase (eNOS) T-786C single nucleotide polymorphism (SNP), implicated in cardiovascular disease susceptibility, could facilitate differentiation between small (< or =5 mm) versus large (> or =10 mm) ruptured aneurysms.


METHODS
In accordance with institutional guidelines, clinical data were recorded prospectively and genomic DNA was isolated from blood samples obtained from 52 aneurysmal subarachnoid hemorrhage (SAH) patients (cases) and 90 randomly selected controls. Samples were assayed for eNOS gene promoter T-786C SNP with the use of gene microarray technology. Statistical analyses included multiple logistic regression.


RESULTS
Although there was no difference in genotype distributions between cases and controls, all 13 patients with large aneurysms were (T/C) heterozygous for the polymorphism, while 9 of 22 patients (41%) with small aneurysms were (T/T or C/C) homozygous (P=0.01). The mean (+/-SD) ruptured aneurysm diameter among all heterozygotes (8.5+/-5.2 mm) was significantly greater than that for C/C (6.0+/-2.3 mm) or T/T (4.7+/-1.8 mm) homozygotes (P=0.04). With the use of multivariate analysis, heterozygosity remained significantly associated with aneurysm size > or =10 mm (P=0.03).


CONCLUSIONS
The eNOS T-786C SNP distinguishes genetically between small and large ruptured aneurysms. Although not predictive of SAH in the population at large, our data suggest that among persons with known intracranial aneurysms, eNOS T-786C genotype may be a factor influencing the size at which an aneurysm ruptures, a finding that should be taken into consideration along with other anatomic features of the aneurysm.
Department of Neurology, Mayo Clinic and Mayo Foundation, Rochester, Minn 55905, USA.
Vini G
VG
Khurana
Youvraj R
YR
Sohni
Wells I
WI
Mangrum
Robyn L
RL
McClelland
Dennis J
DJ
O'Kane
Fredric B
FB
Meyer
Irene
I
Meissner
D017677:Age Distribution; D000368:Aged; D017542:Aneurysm, Ruptured / Q000235:genetics*; D016022:Case-Control Studies; D004252:DNA Mutational Analysis; D005260:Female; D005819:Genetic Markers; D006801:Humans; D002532:Intracranial Aneurysm / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D019001:Nitric Oxide Synthase / Q000235:genetics*; D052250:Nitric Oxide Synthase Type III; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D011237:Predictive Value of Tests; D011446:Prospective Studies; D017678:Sex Distribution
D005819:Genetic Markers; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III