Stroke. 2004;35:e376-e378
Published online before print November 4, 2004,
doi: 10.1161/01.STR.0000147966.81215.be
(Stroke. 2004;35:e376.)
© 2004 American Heart Association, Inc.
Absence of Alpha-1 Antitrypsin Deficiency Alleles (S and Z) in Japanese and Korean Patients With Aneurysmal Subarachnoid Hemorrhage
Taku Yoneyama, MD;
Hidetoshi Kasuya, MD;
Hiroyuki Akagawa, MD;
Hideaki Onda, MD;
Toshiaki Nakajima, MD;
Tomokatsu Hori, MD;
Ituro Inoue, MD;
Jung-Chung Lee, MD;
Tae-Ki Yang, MD
Chul-Jin Kim, MD
From the Department of Neurosurgery (T.Y., H.K.,H.A., H.O., T.H.), Tokyo Women’s Medical University, Tokyo, Japan; the Department of Neurosurgery (J.C.L., T.-K.Y., C.-J.K.), Chonbuk National University, Chonju, Korea; and the Division of Genetic Diagnosis (T.N., I.I.), Institute of Medical Science, University of Tokyo, Tokyo, Japan.
Correspondence to Dr Hidetoshi Kasuya, Department of Neurosurgery, Tokyo Women’s Medical University, Kawada-cho 8-1, Shinjyuku-ku, Tokyo, 162-8666, Japan. E-mail hkasuya{at}nij.twmu.ac.jp
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Abstract
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Background and Purpose— A possible association has been
proposed for the formation of intracranial aneurysm (IA) and
deficiency alleles (
S and
Z) of the
1-antitrypsin (
AAT) gene.
We extensively screened this gene in Japanese and Korean patients
with aneurysmal subarachnoid hemorrhage.
Methods— Seven allelic variants, including S and Z alleles, were genotyped by direct sequencing of genomic DNA obtained from 195 and 189 ruptured IA patients and 195 and 94 controls in Japanese and Koreans, respectively. The haplotype in phase-unknown samples was constructed with the expectation–maximization method. Differences in allelic frequencies between patients and controls were evaluated by Fisher exact test.
Results— No significant differences in allelic frequencies were observed at all 7 variants between ruptured IA patients and controls. We could not detect the S and Z alleles of the AAT gene in Japanese and Korean populations.
Conclusions— AAT deficiency may not be a common genetic risk factor for aneurysmal subarachnoid hemorrhage in Japanese and Koreans.
Key Words: aneurysm • genetics • subarachnoid hemorrhage
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Introduction
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It has recently been recognized that genetic factors are associated
with the formation of intracranial aneurysms (IAs) and subarachnoid
hemorrhage (SAH).
1–3 However, no susceptible genes have
been identified as underlying the cause of IA. The relationship
between alpha-1 antitrypsin (AAT) deficiency and IA formation
has been suggested through an imbalance of protease and AAT,
a major circulating inhibitor of proteases.
4–6 Although
general populations in Japan and Korea rarely have
AAT deficiency
alleles,
7,8 we wanted to verify whether
AAT contributes to the
susceptibility to IA formation in Japanese and Koreans.
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Subjects and Methods
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The University Ethical Committees approved the study, and all
the participants gave written informed consent. The DNA samples
for the association study and genotyping were from 195 ruptured
IA patients and 195 controls from Japan,
3 and 189 ruptured IA
patients and 94 controls from Korea (
Table 1). The presence
of IA was confirmed by surgical findings in patients with SAH.
The age- and sex-matched controls were patients with diseases
other than SAH. The case-to-control ratio was maintained at
1:1 among Japanese and 2:1 among Koreans. All subjects were
of Japanese and Korean ethnicity.
Single Nucleotide Polymorphisms in the AAT Gene and Haplotype Construction
Five common single nucleotide polymorphisms (SNPs) on the AAT gene in Table 2 were researched in the NCBI database (http://www.ncbi.nlm.nih.gov/SNP/). These common SNPs have led to 7 common allelic variants (M1Ala213, M1Val213, M2, M3, M4, S, and Z).9 The phase-unknown allele (haplotype) frequencies of common allelic variants were estimated by an expectation–maximization algorithm based on a maximum likelihood approach using the ARLEQUIN (http://anthro.unige.ch/arlequin) or SNIPALyze (Dynacome) program.
Genotyping
Genomic DNA was extracted from peripheral blood according to a standard method. All primer sets were designed on genomic sequences obtained through the GenBank database, accession number GI: 20543860, to amplify each segment of the AAT gene with Gene Amp PCR system 9700 (PE Applied, Tokyo, Japan) using 10 ng of genomic DNA derived from each of the samples. The primer sequences are available on request. Direct sequencing was performed on polymerase chain reaction-amplified segments, including SNPs, by using ABI 3700 Automated Sequencers (PE Applied Biosystems) under standard conditions.
Allelic Association
Allelic association with IA was evaluated by Fisher exact test for each SNP between the cases and controls.
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Results
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The subjects in this study are summarized in
Table 1. The 5
SNPs were genotyped in all our samples (
Table 2). No significant
differences of genotype frequency were detected in any SNPs
between the cases and controls. The genotype distributions agreed
with those predicted by the Hardy–Weinberg equilibrium.
The estimated allele frequencies in cases and controls are shown
in
Table 3. No significant differences were identified in the
M allelic frequencies between groups.
S and
Z alleles were not
observed in this study.
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Discussion
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The results of this study suggest that specific alleles,
S and
Z, of the
AAT gene are not common genetic risk factors for IA
in Japanese and Koreans, because they were not observed. In
this study, we identified common alleles (
M1–M4,
S, and
Z) of the
AAT gene by direct sequencing for genomic DNA from
aneurysm and control patients. Although
M alleles are widely
dispersed and have been described in several populations, the
occurrence of
S and
Z alleles is virtually restricted to whites
of European descent.
10
It may be difficult to find patients with AAT-deficiency alleles in our Japanese samples, because the mean frequencies of PiS and PiZ are 0.0004 and 0.0002 in Japan.7,8 An analysis of published genetic epidemiologic surveys reported that those in South Korea are 0.0031 and 0.0061, which are higher frequencies than those in Japan.7,8 If AAT were a genetic risk factor in Koreans, we would have found several alleles of S and Z in our Korean patients with ruptured IA.
The inhibition of various proteolytic enzymes, such as neutrophil elastase by AAT, may have an important role in maintaining the integrity of connective tissue, including the blood vessel wall.6 A protease–antiprotease imbalance may have a pathogenetic role in the formation and rupture of IA. Acquired AAT deficiency, caused by the oxidation of methionine in the reactive center, might explain the increased risk of IA and SAH in smokers.6,11
Because the clinical characteristics of SAH are recognized equally in whites, Japanese, and Koreans, genetic factors for SAH may not differ among populations. No significant relationship of S and Z allele frequencies with SAH was reported recently in whites.2 Allelic variants resulting in AAT deficiency may not be associated with the development of IA.
Received July 25, 2004;
accepted August 18, 2004.
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References
|
|---|
- Schievink WI. Genetics of intracranial aneurysms. Neurosurgery. 1997; 40: 651–662.[CrossRef][Medline]
[Order article via Infotrieve]
- Kissela BM, Sauerbeck L, Woo D, Khoury J, Carrozzella J, Pancioli A, Jauch E, Moomaw CJ, Shukla R, Gebel J, Fontaine R, Broderick J. Subarachnoid hemorrhage: a preventable disease with a heritable component. Stroke. 2002; 33: 1321–1326.[Abstract/Free Full Text]
- Onda H, Kasuya H, Yoneyama T, Takakura K, Hori T, Takeda J, Nakajima T, Inoue I. Genomewide-linkage and haplotype-association studies map intracranial aneurysm to chromosome 7q11. Am J Hum Genet. 2001; 69: 804–819.[CrossRef][Medline]
[Order article via Infotrieve]
- Schievink WI, Katzmann JA, Piepgras DG, Schaid DJ. Alpha-1-antitrypsin phenotypes among patients with intracranial aneurysms. J Neurosurg. 1996; 84: 781–784.[Medline]
[Order article via Infotrieve]
- Schievink WI, Prakash UB, Piepgras DG, Mokri B. Alpha 1-antitrypsin deficiency in intracranial aneurysms and cervical artery dissection. Lancet. 1994; 343: 452–453.[CrossRef][Medline]
[Order article via Infotrieve]
- Am Thoracic Society/European Respiratory Society Statement: Standards for the diagnosis and management of individuals with alpha-a antitrypsin deficiency. Am J Respiratory Crit Care Med. 2003; 168: 818–900.[Free Full Text]
- Blanco I, Bustillo EF, Rodriguez MC. Distribution of alpha1-antitrypsin PI S and PI Z frequencies in countries outside Europe: a meta-analysis. Clin Genet. 2001; 60: 431–441.[CrossRef][Medline]
[Order article via Infotrieve]
- de Serres FJ. World racial and ethnic distribution of 1-antitrypsin deficiency. Summary of an analysis of published genetic epidemiologic surveys. Chest. 2002; 122: 1818–1829.[CrossRef][Medline]
[Order article via Infotrieve]
- Brantly M, Nukiwa T, Crystal RG. Molecular basis of alpha-1-antitrypsin deficiency. Am J Med. 1988; 84: 13–31.[Medline]
[Order article via Infotrieve]
- Blanco I, Fernandez E, Bustillo EF. Alpha-1-antitrypsin PI phenotypes S and Z in Europe: an analysis of the published surveys. Clin Genet. 2001; 60: 31–41.[CrossRef][Medline]
[Order article via Infotrieve]
- Gaetani P, Tartara F, Tancioni F, Klersy C, Forlino A, Rodriguez Y, Baena R. Activity of alpha1-antitrypsin and cigarette smoking in subarachnoid haemorrhage from ruptured aneurysm. J Neurol Sci. 1996; 141: 33–38.[CrossRef][Medline]
[Order article via Infotrieve]
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Abstract
Introduction