Lack of association between endoglin intron 7 insertion polymorphism and intracranial aneurysms in a white population: evidence of racial/ethnic differences.
OBJECTIVE
Endoglin is a component of the transforming growth factor-beta receptor complex and is predominantly expressed on cell surfaces of endothelial cells. A polymorphism of the endoglin gene has previously been found to be associated with the occurrence of intracranial aneurysms in a Japanese population. In our study, we investigated whether this polymorphism is associated with the development of cerebral aneurysm in a white population.


METHODS
The study population consisted of 121 white patients who had been treated for intracranial aneurysms, 124 healthy white blood donors, and 15 Japanese volunteers. Exon 7 of the endoglin gene and adjacent intronic sequences were amplified by polymerase chain reaction and analyzed by using an automated laser fluorescence detection system.


RESULTS
A well-known insertion polymorphism (5'-TCCCCC-3', starting 23 bp distal from the 3' end of exon 7) was identified. The allele frequencies of the polymorphism were 35 (14.5%) of 242 alleles in the aneurysm group and 35 (14.1%) of 248 alleles in the white control group, which does not represent a statistically significant difference (P>0.85). The sequence of the polymorphism is complementary to that reported in the previously mentioned Japanese study. However, the 2 polymorphisms are identical. Under this assumption, the allele frequencies differ significantly among the Japanese controls in that particular study and the white controls in our study (27.8% versus 14.1%, respectively; P=0.0003).


CONCLUSIONS
The genetic polymorphism in the vicinity of 3' end of exon 7 in the endoglin gene was not significantly associated with the occurrence of intracranial aneurysms in the white population. There are ethnic-related differences of allele frequencies between our white controls and the previously reported Japanese controls.
Krex
D
D
Department of Neurosurgery, University Hospital Carl Gustav Carus, University of Technology, Dresden, Germany. krex@rcs.urz.tu-dresden.de
Ziegler
A
A
Schackert
H K
HK
Schackert
G
G
D000328:Adult; D000368:Aged; D015703:Antigens, CD; D000071063:Endoglin; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D002532:Intracranial Aneurysm / Q000208:ethnology* / Q000235:genetics*; D007438:Introns; D007564:Japan; D008297:Male; D008875:Middle Aged; D016254:Mutagenesis, Insertional; D011110:Polymorphism, Genetic; D011956:Receptors, Cell Surface; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics*; D044465:White People / Q000235:genetics*
D015703:Antigens, CD; C064206:ENG protein, human; D000071063:Endoglin; D011956:Receptors, Cell Surface; D019010:Vascular Cell Adhesion Molecule-1