DNA polymorphisms of the apolipoprotein B gene in C h e s e coronary artery disease patients Saha N, Tong MC. Tay JSH,Jeyaseelan K, Humphries SE. DNA polymorphisms of the apolipoprotein B gene in Chinese coronary artery disease patients. Clin Genet 1992: 42: 164170. Five restriction fragment length polymorphisms (RFLP) of the apo B gene and their association with serum lipids and apolipoprotein levels have been studied in I39 Chinese patients with angiographically confirmed CAD (mean age 56.2k0.8 years) and 154 healthy Chinese subjects (mean age 44.Ok 1.0 years) of both sexes. The patient group had significantly higher levels of serum total and LDL cholesterol; and apo B (P 35 years.
and A-I1 levels with XbaI RFLP was observed in the Chinese control series (Saha et al. 1992b). No such association was observed in the patient group. However, the number of CAD patients with the X 2 allele was rather small (n= 13) and the standard errors of all the lipid parameters were rather large. Further, the confounding influence of unpredictable factors on serum lipids in the patients due to variable life-style, dietary and therapeutic interventions could not be examined as the number with the uncommon genotype ( X 2 ) was small. Several studies have been carried out to detect association of RFLPs (XbuI and EcoRI) of the apo B gene with serum lipids. Out of 12 control and 9 CAD series including this, an association of X2 allele with serum total cholesterol levels has been observed only in three control and two CAD series (Law et al. 1986, Berg 1986, Deeb et al. 1986, Talmud et al. 1987, Paulweber et al. 1990), while the remaining ones did not reveal any association. Serum total cholesterol levels were not associated with EcoRI RFLP in any of the previous studies, excepting a small sample of Danes (Tybjaerg-Hansen et al. 1991). Serum triglyceride levels were associated positively with the X 2 allele in four studies, negatively in one, while 15 other series did not reveal any association. EcoRI was associated with serum triglyceride levels in only one out of 13 studies (Paulweber et al. 1990). It therefore appears that there is no conclusive evidence of association of apo B RFLPs with CAD, MI or serum lipid levels, although the possibility cannot be ruled out completely in view of strong associations detected in some studies, very low frequencies of the rare alleles of some RFLPs in the Chinese and the younger age of the present control series. More extensive studies with adequate sample size according to allele frequencies in diverse populations seem to be the logical future direction of research. 168
Acknowledgements This study was generously supported by the Singapore National Heart Association. National University of Singapore and Singapore Anti-Tuberculosis Association. The technical assistance of Mdrn C. H. Ho and Mrs Jumiah Bte Basair and the technical staff of SATA and the secretarial help of Miss Tay Siew Leng are gratefully acknowledged. The authors are grateful to the Medical Director of SATA for providing all the facilities for the study, Mr Piara Singh for his help with computer programmes and Ms Hiroko Paul-Hayase for supplying the apoB probe DNA. Dr S. Humphries is supported by the British Heart Foundation and the Sunley Research Trust.
References Aburatani H, Murase T, Takaku F, ltoh H, Matsumoto A, ltakura H. Apolipoprotein B-gene polymorphism and myocardial infarction. N Engl J Med 1987: 3178: 52. Aburatani H, Matsumoto A, ltoh H, Yamada N, Murase T, Takaku F, ltakura H. A study of DNA polymorphism in the apolipoprotein B gene in a Japanese population. Atherosclerosis 1988: 72: 7 1-76. Avogaro P, Bittolo Bon G . Cazzolato G, Quinci GB. Are apolipoproteins better discriminators than lipids for atherosclerosis? Lancet 1979: i: 901-903. Avogaro P,Bittolo Bon G, Cazzolato G, Rorai E. Relationship between apolipoproteins and chemical components of lipoproteins in survivors of myocardial infarction. Atherosclerosis 1980: 37: 69-76. Barni N, Talmud PJ, Carlsson P, Azoulay M, Darnfors C, Harding D, Weil D, Gzexhik KH, Bjursell G, Junien C, Williamson R, Humphries SE. The isolation of genomic recombinants for the human apolipoprotein B gene and the mapping of three common DNA polymorphisms of the gene - a useful marker for the human chromosome 2. Hum Genet 1986: 73: 313-319. Berg K. DNA polymorphism at the apolipoprotein B locus is associated with lipoprotein level. Clin Genet 1986: 30: 515-520.
Boerwinkle E. Chan L. A three codon insertionfdeletion polymorphism in the signal peptide region of the human apolipoprotein B (Apo B) gene directly typed by the polymerase chain reaction. NAR 1989: 17: 4003. Breslow J. Apolipoprotein genetic variation and human disease. Physiol Rev 1988: 68: 85-132. Brown MS, Goldstein JL. A receptor-mediated pathway for cholesterol homeostasis. Science 1986: 232 34-47.
DNA polymorphisms of apo B gene Carlsson P, Darnfors C, Olofsson S-0, Bjursell G. Analysis of human apolipoprotein B gene: complete structure of the B74 region. Gene I986 49: 29-5 I . Castelli WP. Doyle JT. Gordon T, Hames CG, Hjortland MC, Hulley SB, Kagan A, Zukel WJ. HDL cholesterol and other lipids in coronary heart disease. The co-operative lipoprotein phenotyping study. Circulation 1977: 55: 767-772. Darnfors C, Wiklund 0, Nilsson J. Gerard B, Carlsson P, Johansson S, Bondjers G, Bjursell (3. Lack of correlation between the apolipoprotein B XbaI polymorphism and blood lipid levels in a Swedish population. Atherosclerosis 1989: 75: 183-187. Deeb S, Failor A. Brown BG, Brundzell JD, Albers JJ, Motulsky AG. In: Molecular genetics of apolipoproteins and coronary heart disease. Cold Spring Harbar Symposium on Quantitative Bioloey Nett 1988: 403. Demant T, Houlston RS, Caslake MJ, Series JJ, Shepherd J. Packard CJ, Humphries SE. The catabolic rate of low density lipoprotein is influenced by variation in the apolipoprotein B gene. J Clin Invest 1988: 82: 797-802. Dunning AM, Tikkanen MJ, Enholm C , Butler R. Humphries SE. Relationships between DNA and protein polymorphisms of apolipoprotein B. Hum Genet 1988: 78: 328-329. Ferns GAA. Galton DJ. Frequency of Xbul polymorphism in myocardial infarct survivors. Lancet 1986: ii: 572. Friedewald WT, Levy RI. Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma without use of the preparative ultracentrifugation. Clin Chem 1972 18: 499-502. Frossard PM. Gonzales PA. Protter AA, Coleman RT, Funke H. Assman G. Pwll RFLP in the 5’ of the human apolipoprotein B gene. Nucleic Acid Res 1986: 14: 4373. Grnest JJ, Ordovas JM, McNamara JR. Robbins AM, Meade T. Cohn SD, Salem DN. Wilson PWF, Masharani U. Frossard PM, Schaefer EJ. DNA polymorphisms of the apolipoprotein B gene in patients with premature coronary artery disease. Atherosclerosis 1990: 82: 7-17. Hegele RA, Huang L-S, Herbert PN, Blum CB, Buring JE, Hennekens CH, Breslow JL. Apolipoprotein-B gene polymorphisms associated with myocardial infarction. N Engl J Med 1986: 315: 1509-1515. Houlston RS, Turner PR, Revill J, Lewis B, Humphries SE. The fractional catabolic rate of low density lipoprotein in normal individuals is influenced by variation in the apolipoprotein B gene: a preliminary study. Atherosclerosis 1988: 76: 81-85. Humphries SE. DNA polymorphisms of the apolipoprotein genes - their use in the investigation of the genetic component of hyperlipidaemia and atherosclerosis. Atherosclerosis 1988: 72: 89-108. Humphries S, Talmud P. Monsalve V, McKeigue P. RFLP studies in different ethnic groups. Atherosclerosis 1989: 75: 249-250. Jenner K, Sidoli A, Ball M, Rodriguez JR, Pagani F, Guidici G, Vergani C. Mann J, Baralle FE, Shoulders CC. Characterisation of genetic markers in the 3’ t:nd of the apo B gene and their use in family and population studies. Atherosclerosis 1988: 69: 3949. Keys A. Aravanis C, Blackburn H, Van Buchem FSP, Buzina R, Djordjevic BS, Fidanza F, Karvmen MJ, Menotti A, Puddu V, Taylor HL. Probability of middle-aged men developing coronary heart disease in ]Eve years. Circulation 1972: 45: 815-828. Kunkel LM, Smith KD, Boyer SH et al. Analysis of human Y chromosome-specific reiterated DNA chromosome variants. Proc Natl Acad Sci USA 1977 74: 124S-1249. Law A, Powell LM, Brunt H, Knott T.1, Altman DG, Rajput J, Wallis SC. Pease RJ, Priestley LM, Scott J, Miller GJ, Miller NE. Common DNA polymorphism within coding se-
quence of apolipoprotein B gene associated with altered lipid levels. Lancet 1986: i: 1301-1303. Levy RI. Cholesterol, lipoproteins and heart disease: present status and future prospects. Clin Chem 1981: 27: 653-662. Lewis B. The lipoproteins: predictors. protectors and pathogens. Br Med J 1983: 287: 1161-1 164. Miller NE. Metabolic determinants of plasma highdensity lipoprotein concentrations in humans. In: Malmendier CL, Alaupovic P. Lipoproteins and atherosclerosis. New York: Plenum Publishing Corporation. 1987: I 11-1 15. Miller NE, Forde OH, Thelle DS, Mjos DD. The Tromso heart study. High-density lipoprotein and coronary heart disease: a prospective case-control study. Lancet 1977: i: 695-697. Monsalve MY Young R, Jobsis J, Wiseman SA. Dhamu S, Powell JT, Greenhalgh RM, Humphries SE. DNA polymorphisms of the gene for Apolipoprotein B in patients with peripheral and coronary artery disease. Atherosclerosis 1988: 70: 123-129. Myant NB, Gallagher J, Barbir M, Thompson GR, Wile D, Humphries SE. Restriction fragment length polymorphisms in the apo B gene in relation to coronary artery disease. Atherosclerosis 1989: 77: 193-201. Olofsson S-0. Bjursell G, Bostrom K. Carlsson P, Elovson J. Protter AA, Reuben MA. Bondjers G. Apolipoprotein B: structure, biosynthesis and role in the lipoprotein assembly process. Atherosclerosis 1987: 68: 1-17. Paulweber B, Fried1 W, Krempler E, Humphries SE. Sandhofer F. Association of DNA polymorphism at the apo B gene locus with coronary heart disease and Serum VLDL levels. Arteriosclerosis 1Y90 10: 17-24. Peacock R. Dunning A, Hamsten A. Tornvall P. Humphries SE, Talmud P. Apolipoprotein B gene polymorphisms lipoproteins and coronary atherosclerosis; a study of young myocardial infarction survivors and healthy population based individuals. Atherosclerosis IYY2: 92: I5 1-1 64. Priestley L, Knott T. Wallis S, Powell L, Pease R, Simon A. Scott J. RFLP for the human apolipoprotein B gene: 1. BumHI; 11, EcoRI; Ill. EcoRV; IY Mspl; V, Xbul. cDNA clones encoding. Nucleic Acid Res 1985: 13: 6789-6793. Protter AA. Hardman DA, Sat0 KY, Schilling JW, Yamanaka M, Hort YJ, Hjerrild KA, Chen GC, Kane JP. Analysis of the entire 8-26 region of human apolipoprotein B. Proc Natl Acad Sci USA 1986: 83: 5678-5682. Rajput-Williams J, Wallis SC. Yarnell J. Bell GI. Knott TJ, Sweetnam P, Cox N. Miller NE, Scott J. Variation of apolipoprotein B gene is associated with obesity, high blood cholesterol levels and increased risk of coronary heart disease. Lancet 1988: ii: 1442-1446. Saha N. Serum high-density lipoprotein cholesterol, apolipoprotein A-I, A-I1 and. B levels in Singapore ethnic groups. Atherosclerosis 1987: 68: 117-121. Saha N, Humphries SE. Frequencies of alleles of DNA RFLP (XbaI) of the Apolipoprotein B gene in ethnic groups with differential mortality from CAD. Am J Hum Genet 1988: 43: A236. Saha N, Toh CCS, Ghosh MB. Genetic association in myocardial infarction. Ethnicity, ABO, Rh, Lea, XgY blood groups. G6PD deficiency and abnormal haemoglobin. J Med Genet 1973: 10: 340-345. Saha N, Tay JSH, Chew LS. Influence of apolipoprotein B signal peptide insertion/deletion polymorphism on serum lipids and apolipoproteins in a Chinese population. CIin Genet 1992a: 41: 152-156. Saha N, Tay JSH. Serum lipid and apolipoproteins (Apo A-I. A-I1 and B) in the Chinese of Mainland and Singapore. Proc Nutr Soc 1992: in press. Saha N, Tay JSH, Humphries SE. Apolipoprotein B-gene DNA polymorphisms (XbaI and EcoRI), serum lipids and apo-
169
Saha et al. lipoproteins in healthy Chinese. Genet Epidemiol 1992b: 9: 1-10.
Series J, Cameron 1. Caslake M, Gaffney CJ, Packard CJ, Shepherd J. The XbuI polymorphism of the apolipoprotein B gene influences the degradation of low density lipoprotein in vitro. Biochem Biophys Acta 1989: 1003: 183-188. Shoulders CC. Myant NB. Sidoli A, Rodriguez JC. Cortese C , Baralle FE, Cortese R. Molecular cloning of human LDL apolipoprotein B cDNA: evidence for more than one gene per haploid genome. Atherosclerosis 1985: 58: 277-289. Southern E. Detection of specific sequence among DNA fragments separated by gel electrophoresis. J Mol Biol 1975: 98: 503-5 17. Talmud PJ, Azoulay M. Junien C, Carlsson P, Weil D, Grzeschik KH. Bjursell G. Williamson R, Humphries SE. Two DNA polymorphisms of the human apolipoprotein B gene - a useful marker for human chromosome 2. Cytogenet Cell Genet 1985: 40: 759. Talmud PJ. Barni N, Kessling AM, Carlsson P, Darnfors C, Bjursell G, Galton D. Wynn V. Kirk H, Hayden MR, Humphries SE. Apolipoprotein B gene variants are involved in the determination of serum cholesterol levels: a study of normo- and hyperlipidaernic individuals. Atherosclerosis 1987: 67: 81-89. Tan PY, Ng TB. Saha N. Dietary intakes of three ethnic groups of Singapore. Proc Nutr Soc 1984: 43: 135A.
170
Tikkanen MJ, Xu C-F, Hamalainen T, Talmud P, Sarna S, Huttunen JK. Pietinen P, Humphries S. XbaI polymorphism of the apolipoprotein B gene influences plasma lipid response to diet intervention. Clin Genet 1990: 37: 327-334. Tybjaerg-Hansen A, Nordestggard BG, Gerdes LU,Humphries SE. Variation of apolipoprotein B gene is associated with myocardial infarction and lipoprotein levels in Danes. Atherosclerosis. 199 I : 89: 69-8 1. Visvikis S, Chan L, Siest G, Drouin P, Boerwinkle E. An insertion/deletion polymorphism in the signal peptide of the human apolipoprotein 8 gene. Hum Genet 1990: 8 4 373-375. Wiklund 0, Darnfors C, Olofsson SO, Wilheimsen L, Bondjers G. XhuI restriction fragment length polymorphism of apolipoprotein B in Swedish myocardial infarction patients. Eur J Clin rnvest 1989 19 255-258. Xu C-F, Nanjee MN, Sevill J, Talmud PJ, Angelic0 F, Del Ben M, Antonini R, Mazzarella B, Miller N, Humphries SE. Variation at the apolipoprotein (apo) AI-CII-AIV gene cluster and apo B gene loci is associated with lipoprotein and apolipoprotein levels in Italian children. Am J Hum Genet 1990a: 47: 429-439. Xu C-F, Tikkanen MJ, Huttune JK, Pietinen P, Butler R, Humphries S, Talmud P. Apolipoprotein signal peptide insertion/deletion polymorphism is associated with Ag epitomes and involved in the determination of serum triglyceride levels. J Lipid Res 1990b: 31: 1255-1261.
and A-I1 levels with XbaI RFLP was observed in the Chinese control series (Saha et al. 1992b). No such association was observed in the patient group. However, the number of CAD patients with the X 2 allele was rather small (n= 13) and the standard errors of all the lipid parameters were rather large. Further, the confounding influence of unpredictable factors on serum lipids in the patients due to variable life-style, dietary and therapeutic interventions could not be examined as the number with the uncommon genotype ( X 2 ) was small. Several studies have been carried out to detect association of RFLPs (XbuI and EcoRI) of the apo B gene with serum lipids. Out of 12 control and 9 CAD series including this, an association of X2 allele with serum total cholesterol levels has been observed only in three control and two CAD series (Law et al. 1986, Berg 1986, Deeb et al. 1986, Talmud et al. 1987, Paulweber et al. 1990), while the remaining ones did not reveal any association. Serum total cholesterol levels were not associated with EcoRI RFLP in any of the previous studies, excepting a small sample of Danes (Tybjaerg-Hansen et al. 1991). Serum triglyceride levels were associated positively with the X 2 allele in four studies, negatively in one, while 15 other series did not reveal any association. EcoRI was associated with serum triglyceride levels in only one out of 13 studies (Paulweber et al. 1990). It therefore appears that there is no conclusive evidence of association of apo B RFLPs with CAD, MI or serum lipid levels, although the possibility cannot be ruled out completely in view of strong associations detected in some studies, very low frequencies of the rare alleles of some RFLPs in the Chinese and the younger age of the present control series. More extensive studies with adequate sample size according to allele frequencies in diverse populations seem to be the logical future direction of research. 168
Acknowledgements This study was generously supported by the Singapore National Heart Association. National University of Singapore and Singapore Anti-Tuberculosis Association. The technical assistance of Mdrn C. H. Ho and Mrs Jumiah Bte Basair and the technical staff of SATA and the secretarial help of Miss Tay Siew Leng are gratefully acknowledged. The authors are grateful to the Medical Director of SATA for providing all the facilities for the study, Mr Piara Singh for his help with computer programmes and Ms Hiroko Paul-Hayase for supplying the apoB probe DNA. Dr S. Humphries is supported by the British Heart Foundation and the Sunley Research Trust.
References Aburatani H, Murase T, Takaku F, ltoh H, Matsumoto A, ltakura H. Apolipoprotein B-gene polymorphism and myocardial infarction. N Engl J Med 1987: 3178: 52. Aburatani H, Matsumoto A, ltoh H, Yamada N, Murase T, Takaku F, ltakura H. A study of DNA polymorphism in the apolipoprotein B gene in a Japanese population. Atherosclerosis 1988: 72: 7 1-76. Avogaro P, Bittolo Bon G . Cazzolato G, Quinci GB. Are apolipoproteins better discriminators than lipids for atherosclerosis? Lancet 1979: i: 901-903. Avogaro P,Bittolo Bon G, Cazzolato G, Rorai E. Relationship between apolipoproteins and chemical components of lipoproteins in survivors of myocardial infarction. Atherosclerosis 1980: 37: 69-76. Barni N, Talmud PJ, Carlsson P, Azoulay M, Darnfors C, Harding D, Weil D, Gzexhik KH, Bjursell G, Junien C, Williamson R, Humphries SE. The isolation of genomic recombinants for the human apolipoprotein B gene and the mapping of three common DNA polymorphisms of the gene - a useful marker for the human chromosome 2. Hum Genet 1986: 73: 313-319. Berg K. DNA polymorphism at the apolipoprotein B locus is associated with lipoprotein level. Clin Genet 1986: 30: 515-520.
Boerwinkle E. Chan L. A three codon insertionfdeletion polymorphism in the signal peptide region of the human apolipoprotein B (Apo B) gene directly typed by the polymerase chain reaction. NAR 1989: 17: 4003. Breslow J. Apolipoprotein genetic variation and human disease. Physiol Rev 1988: 68: 85-132. Brown MS, Goldstein JL. A receptor-mediated pathway for cholesterol homeostasis. Science 1986: 232 34-47.
DNA polymorphisms of apo B gene Carlsson P, Darnfors C, Olofsson S-0, Bjursell G. Analysis of human apolipoprotein B gene: complete structure of the B74 region. Gene I986 49: 29-5 I . Castelli WP. Doyle JT. Gordon T, Hames CG, Hjortland MC, Hulley SB, Kagan A, Zukel WJ. HDL cholesterol and other lipids in coronary heart disease. The co-operative lipoprotein phenotyping study. Circulation 1977: 55: 767-772. Darnfors C, Wiklund 0, Nilsson J. Gerard B, Carlsson P, Johansson S, Bondjers G, Bjursell (3. Lack of correlation between the apolipoprotein B XbaI polymorphism and blood lipid levels in a Swedish population. Atherosclerosis 1989: 75: 183-187. Deeb S, Failor A. Brown BG, Brundzell JD, Albers JJ, Motulsky AG. In: Molecular genetics of apolipoproteins and coronary heart disease. Cold Spring Harbar Symposium on Quantitative Bioloey Nett 1988: 403. Demant T, Houlston RS, Caslake MJ, Series JJ, Shepherd J. Packard CJ, Humphries SE. The catabolic rate of low density lipoprotein is influenced by variation in the apolipoprotein B gene. J Clin Invest 1988: 82: 797-802. Dunning AM, Tikkanen MJ, Enholm C , Butler R. Humphries SE. Relationships between DNA and protein polymorphisms of apolipoprotein B. Hum Genet 1988: 78: 328-329. Ferns GAA. Galton DJ. Frequency of Xbul polymorphism in myocardial infarct survivors. Lancet 1986: ii: 572. Friedewald WT, Levy RI. Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma without use of the preparative ultracentrifugation. Clin Chem 1972 18: 499-502. Frossard PM. Gonzales PA. Protter AA, Coleman RT, Funke H. Assman G. Pwll RFLP in the 5’ of the human apolipoprotein B gene. Nucleic Acid Res 1986: 14: 4373. Grnest JJ, Ordovas JM, McNamara JR. Robbins AM, Meade T. Cohn SD, Salem DN. Wilson PWF, Masharani U. Frossard PM, Schaefer EJ. DNA polymorphisms of the apolipoprotein B gene in patients with premature coronary artery disease. Atherosclerosis 1990: 82: 7-17. Hegele RA, Huang L-S, Herbert PN, Blum CB, Buring JE, Hennekens CH, Breslow JL. Apolipoprotein-B gene polymorphisms associated with myocardial infarction. N Engl J Med 1986: 315: 1509-1515. Houlston RS, Turner PR, Revill J, Lewis B, Humphries SE. The fractional catabolic rate of low density lipoprotein in normal individuals is influenced by variation in the apolipoprotein B gene: a preliminary study. Atherosclerosis 1988: 76: 81-85. Humphries SE. DNA polymorphisms of the apolipoprotein genes - their use in the investigation of the genetic component of hyperlipidaemia and atherosclerosis. Atherosclerosis 1988: 72: 89-108. Humphries S, Talmud P. Monsalve V, McKeigue P. RFLP studies in different ethnic groups. Atherosclerosis 1989: 75: 249-250. Jenner K, Sidoli A, Ball M, Rodriguez JR, Pagani F, Guidici G, Vergani C. Mann J, Baralle FE, Shoulders CC. Characterisation of genetic markers in the 3’ t:nd of the apo B gene and their use in family and population studies. Atherosclerosis 1988: 69: 3949. Keys A. Aravanis C, Blackburn H, Van Buchem FSP, Buzina R, Djordjevic BS, Fidanza F, Karvmen MJ, Menotti A, Puddu V, Taylor HL. Probability of middle-aged men developing coronary heart disease in ]Eve years. Circulation 1972: 45: 815-828. Kunkel LM, Smith KD, Boyer SH et al. Analysis of human Y chromosome-specific reiterated DNA chromosome variants. Proc Natl Acad Sci USA 1977 74: 124S-1249. Law A, Powell LM, Brunt H, Knott T.1, Altman DG, Rajput J, Wallis SC. Pease RJ, Priestley LM, Scott J, Miller GJ, Miller NE. Common DNA polymorphism within coding se-
quence of apolipoprotein B gene associated with altered lipid levels. Lancet 1986: i: 1301-1303. Levy RI. Cholesterol, lipoproteins and heart disease: present status and future prospects. Clin Chem 1981: 27: 653-662. Lewis B. The lipoproteins: predictors. protectors and pathogens. Br Med J 1983: 287: 1161-1 164. Miller NE. Metabolic determinants of plasma highdensity lipoprotein concentrations in humans. In: Malmendier CL, Alaupovic P. Lipoproteins and atherosclerosis. New York: Plenum Publishing Corporation. 1987: I 11-1 15. Miller NE, Forde OH, Thelle DS, Mjos DD. The Tromso heart study. High-density lipoprotein and coronary heart disease: a prospective case-control study. Lancet 1977: i: 695-697. Monsalve MY Young R, Jobsis J, Wiseman SA. Dhamu S, Powell JT, Greenhalgh RM, Humphries SE. DNA polymorphisms of the gene for Apolipoprotein B in patients with peripheral and coronary artery disease. Atherosclerosis 1988: 70: 123-129. Myant NB, Gallagher J, Barbir M, Thompson GR, Wile D, Humphries SE. Restriction fragment length polymorphisms in the apo B gene in relation to coronary artery disease. Atherosclerosis 1989: 77: 193-201. Olofsson S-0. Bjursell G, Bostrom K. Carlsson P, Elovson J. Protter AA, Reuben MA. Bondjers G. Apolipoprotein B: structure, biosynthesis and role in the lipoprotein assembly process. Atherosclerosis 1987: 68: 1-17. Paulweber B, Fried1 W, Krempler E, Humphries SE. Sandhofer F. Association of DNA polymorphism at the apo B gene locus with coronary heart disease and Serum VLDL levels. Arteriosclerosis 1Y90 10: 17-24. Peacock R. Dunning A, Hamsten A. Tornvall P. Humphries SE, Talmud P. Apolipoprotein B gene polymorphisms lipoproteins and coronary atherosclerosis; a study of young myocardial infarction survivors and healthy population based individuals. Atherosclerosis IYY2: 92: I5 1-1 64. Priestley L, Knott T. Wallis S, Powell L, Pease R, Simon A. Scott J. RFLP for the human apolipoprotein B gene: 1. BumHI; 11, EcoRI; Ill. EcoRV; IY Mspl; V, Xbul. cDNA clones encoding. Nucleic Acid Res 1985: 13: 6789-6793. Protter AA. Hardman DA, Sat0 KY, Schilling JW, Yamanaka M, Hort YJ, Hjerrild KA, Chen GC, Kane JP. Analysis of the entire 8-26 region of human apolipoprotein B. Proc Natl Acad Sci USA 1986: 83: 5678-5682. Rajput-Williams J, Wallis SC. Yarnell J. Bell GI. Knott TJ, Sweetnam P, Cox N. Miller NE, Scott J. Variation of apolipoprotein B gene is associated with obesity, high blood cholesterol levels and increased risk of coronary heart disease. Lancet 1988: ii: 1442-1446. Saha N. Serum high-density lipoprotein cholesterol, apolipoprotein A-I, A-I1 and. B levels in Singapore ethnic groups. Atherosclerosis 1987: 68: 117-121. Saha N, Humphries SE. Frequencies of alleles of DNA RFLP (XbaI) of the Apolipoprotein B gene in ethnic groups with differential mortality from CAD. Am J Hum Genet 1988: 43: A236. Saha N, Toh CCS, Ghosh MB. Genetic association in myocardial infarction. Ethnicity, ABO, Rh, Lea, XgY blood groups. G6PD deficiency and abnormal haemoglobin. J Med Genet 1973: 10: 340-345. Saha N, Tay JSH, Chew LS. Influence of apolipoprotein B signal peptide insertion/deletion polymorphism on serum lipids and apolipoproteins in a Chinese population. CIin Genet 1992a: 41: 152-156. Saha N, Tay JSH. Serum lipid and apolipoproteins (Apo A-I. A-I1 and B) in the Chinese of Mainland and Singapore. Proc Nutr Soc 1992: in press. Saha N, Tay JSH, Humphries SE. Apolipoprotein B-gene DNA polymorphisms (XbaI and EcoRI), serum lipids and apo-
169
Saha et al. lipoproteins in healthy Chinese. Genet Epidemiol 1992b: 9: 1-10.
Series J, Cameron 1. Caslake M, Gaffney CJ, Packard CJ, Shepherd J. The XbuI polymorphism of the apolipoprotein B gene influences the degradation of low density lipoprotein in vitro. Biochem Biophys Acta 1989: 1003: 183-188. Shoulders CC. Myant NB. Sidoli A, Rodriguez JC. Cortese C , Baralle FE, Cortese R. Molecular cloning of human LDL apolipoprotein B cDNA: evidence for more than one gene per haploid genome. Atherosclerosis 1985: 58: 277-289. Southern E. Detection of specific sequence among DNA fragments separated by gel electrophoresis. J Mol Biol 1975: 98: 503-5 17. Talmud PJ, Azoulay M. Junien C, Carlsson P, Weil D, Grzeschik KH. Bjursell G. Williamson R, Humphries SE. Two DNA polymorphisms of the human apolipoprotein B gene - a useful marker for human chromosome 2. Cytogenet Cell Genet 1985: 40: 759. Talmud PJ. Barni N, Kessling AM, Carlsson P, Darnfors C, Bjursell G, Galton D. Wynn V. Kirk H, Hayden MR, Humphries SE. Apolipoprotein B gene variants are involved in the determination of serum cholesterol levels: a study of normo- and hyperlipidaernic individuals. Atherosclerosis 1987: 67: 81-89. Tan PY, Ng TB. Saha N. Dietary intakes of three ethnic groups of Singapore. Proc Nutr Soc 1984: 43: 135A.
170
Tikkanen MJ, Xu C-F, Hamalainen T, Talmud P, Sarna S, Huttunen JK. Pietinen P, Humphries S. XbaI polymorphism of the apolipoprotein B gene influences plasma lipid response to diet intervention. Clin Genet 1990: 37: 327-334. Tybjaerg-Hansen A, Nordestggard BG, Gerdes LU,Humphries SE. Variation of apolipoprotein B gene is associated with myocardial infarction and lipoprotein levels in Danes. Atherosclerosis. 199 I : 89: 69-8 1. Visvikis S, Chan L, Siest G, Drouin P, Boerwinkle E. An insertion/deletion polymorphism in the signal peptide of the human apolipoprotein 8 gene. Hum Genet 1990: 8 4 373-375. Wiklund 0, Darnfors C, Olofsson SO, Wilheimsen L, Bondjers G. XhuI restriction fragment length polymorphism of apolipoprotein B in Swedish myocardial infarction patients. Eur J Clin rnvest 1989 19 255-258. Xu C-F, Nanjee MN, Sevill J, Talmud PJ, Angelic0 F, Del Ben M, Antonini R, Mazzarella B, Miller N, Humphries SE. Variation at the apolipoprotein (apo) AI-CII-AIV gene cluster and apo B gene loci is associated with lipoprotein and apolipoprotein levels in Italian children. Am J Hum Genet 1990a: 47: 429-439. Xu C-F, Tikkanen MJ, Huttune JK, Pietinen P, Butler R, Humphries S, Talmud P. Apolipoprotein signal peptide insertion/deletion polymorphism is associated with Ag epitomes and involved in the determination of serum triglyceride levels. J Lipid Res 1990b: 31: 1255-1261.
