Abstract
Familial hypercholesterolemia (FH) is an autosomal dominant disease caused by a multitude of low-density lipoprotein (LDL) receptor gene mutations. The LDL receptor is a cell surface trans-membrane protein that mediates the uptake & lysosomal degradation of plasma LDI., thereby providing cholesterol to cells. Affected individuals have elevated plasma levels of LDL, which causes premature coronary atherosclerosis. FH has an estimated worldwide prevalence of 0.2%. In some subpopulations there is an increased frequency of FH and specific LDL receptor mutations are found to be common due to ‘founder gene effect’. Overall, more than 300 naturally occurring LDL receptor mutations have been described. To data upto ten LDL receptor gene mutations have been identified in Indians in South Africa, suggesting increased incidence of FH among Indians. Most mutations have occurred at CpG dinucleotide, a mutational hotspot in human genetic disease. In our study in 25 hypercholesterolemic subjects we have identified two novel insertion mutations in two patients. But the mutations underlying FH are still undefined in the majority of cases. Mutational heterogeneity on the other-hand has complicated disease diagnosis at DNA level. These findings warrant application of a generalized mutation screening method in search for new LDL receptor gene defects.
Key Words: Familial hypercholesterolemia (FH), LDL receptor, Mutations, Atherosclerosis, DNA diagnosis
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References
- 1.Brown M.S., Goldstein J.L. A receptor mediated pathway for cholesterol homeostasis. Science. 1986;232:34–47. doi: 10.1126/science.3513311. [DOI] [PubMed] [Google Scholar]
- 2.Goldstein J.L., Hobbs H.H., Brown M.S. Familial hypercholesterolemia. In: Scriver C.R., Beaudet A.L., Sly W.S., Valle B., editors. The metabolic basis of inherited disease. 7th edn. NewYork: McGraw-Hill; 1995. pp. 1980–2030. [Google Scholar]
- 3.Tolleshaug H., Goldstein J.L., Schneider W.J., Brown M.S. Post-translational processing of the LDL receptor and its genetic disruption in familial hypercholesterolemia. Cell. 1982;30:715–724. doi: 10.1016/0092-8674(82)90276-8. [DOI] [PubMed] [Google Scholar]
- 4.Yamamoto T., Davis C.G., Brown M.S., Schneider W.J., Casey M.L., Goldstein J.L., Russell D.W. The Human LDL receptor: A cysteine-rich protein with multiple Alu sequences in its mRNA. Cell. 1984;39:27–38. doi: 10.1016/0092-8674(84)90188-0. [DOI] [PubMed] [Google Scholar]
- 5.Sudhof T.C., Goldstein J.L., Brown M.S., Russell D.W. The LDL receptor gene: A mosaic of exons shared with different proteins. Science. 1985;228:815–822. doi: 10.1126/science.2988123. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Goldstein J.L., Brown M.S. Regulation of the mevalonate pathway. Nature (London) 1990;343:425–430. doi: 10.1038/343425a0. [DOI] [PubMed] [Google Scholar]
- 7.Hobbs H.H., Brown M.S., Goldstein J.L. Molecular genetics of the LDL receptor gene in familial hypercholesterolemia. Hum. Mutat. 1992;1:445–466. doi: 10.1002/humu.1380010602. [DOI] [PubMed] [Google Scholar]
- 8.Hobbs H.H., Brown M.S., Russell D.W., Davignon J., Goldstein J.L. Deletion in the gene for low density lipoprotein receptor in a majority of French Canadians with familial hypercholesterolemia. New. Eng. J. Med. 1987;317:734–737. doi: 10.1056/NEJM198709173171204. [DOI] [PubMed] [Google Scholar]
- 9.Hobbs H.H., Leitersdorf E., Goldstein J.L., Brown M.S., Russell D.W. Multiple crm mutation in familial hypercholesterolemia. J. Clin. Invest. 1988;81:909–917. doi: 10.1172/JCI113402. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Leitersdorf E., Tobin E.J., Davignon J., Hobbs H.H. Common low-density lipoprotein receptor mutations in the French Canadian population. J. Clin. Invest. 1990;85:1014–1023. doi: 10.1172/JCI114531. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Leitersdorf E., Westhuyzen D.R., Coetzee G.A., Hobbs H.H. Two common low-density lipoprotein receptor gene mutations cause familial hypercholesterolemia in Afrikaners. J. Clin. Invest. 1989;84:954–961. doi: 10.1172/JCI114258. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Mehta K.D., Chen W.J., Goldstein J.L., Brown M.S. The low density lipoprotein receptor in Xenopus laevis: Five domains that resemble the human receptor. J. Biol. Chem. 1991;266:10406–10414. [PubMed] [Google Scholar]
- 13.Lehrman M.A., Schneider W.J., Brown M.S., Davis C.G., Elhanmer A., Russell D.W., Goldstein J.L. The Lebanese allele at the low-density lipoprotein receptor locus. J. Biol. Chem. 1987;262:401–410. [PubMed] [Google Scholar]
- 14.Rubinsztein D.C., Coetzee G.A., Marias A.D., Leitersdorf E., Seftel H.C., Westhuyzen D.R. Identification and properties of the proline 664-leucine mutant LDL receptor in South Africans of Indian origin. J. Lipid. Res. 1992;33:1647–1655. [PubMed] [Google Scholar]
- 15.Hobbs H.H., Brown M.S., Goldstein J.L., Russell D.W. Deletion of exon encoding cysteine-rich repeat of LDL receptor alters its binding specificity in a subject with familial hypercholesterolemia. J. Biol. Chem. 1986;26:13114–13120. [PubMed] [Google Scholar]
- 16.Hobbs H.H., Russell D.W., Brown M.S., Goldstein J.L. The LDL receptor locus and familial hypercholesterolemia: Mutational analysis of a membrane protein. Annu. Rev. Genet. 1990;24:133–170. doi: 10.1146/annurev.ge.24.120190.001025. [DOI] [PubMed] [Google Scholar]
- 17.Davis C.G., Lehrman M.A., Russell D.W., Anderson R.G.W., Brown M.S., Goldstein J.L. The J. D. mutation in familial hypercholesterolemia: Amino acid substitution in cytoplasmic domain impedes internalization of LDL receptors. Cell. 1986;45:15–24. doi: 10.1016/0092-8674(86)90533-7. [DOI] [PubMed] [Google Scholar]
- 18.Lehrman M.A., Schneider W.J., Sudhof T.C., Brown M.S., Goldstein J.L., Russell D.W. Mutation in LDL receptor: Alu-Alu recombination deleted exons encoding transmembrane and cytoplasmic domains. Science. 1985;227:140–146. doi: 10.1126/science.3155573. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Aalto-Setala K., Helve E., Kovanen P.T., Kontula K. A finnish type of low-density lipoprotein receptor gene mutation (FH-Helsinki) deletes exons encoding the carboxy-terminal part of the receptor and creates an internalization-defective phenotype. J. Clin. Invest. 1989;84:498–505. doi: 10.1172/JCI114192. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Davis C.G., Goldstein J.L., Sudhof T.C., Anderson R.G.W., Russell D.W., Brown M.S. Acid-dependent ligand dissociation and recycling of LDL receptor mediated by growth factor homology region. Nature (London) 1987;326:760–765. doi: 10.1038/326760a0. [DOI] [PubMed] [Google Scholar]
- 21.Miyake Y., Tajima S., Funahashi T., Yamamoto A. Analysis of a recycling-impaired mutant of low-density receptor in familial hypercholesterolemia. J. Biol. Chem. 1989;264:16584–16590. [PubMed] [Google Scholar]
- 22.Stoppa-Lyonnet D., Carter P.E., Meo T., Tosi M. Cluster of intragenic Alu repeats predispose the human C1 inhibitor locus to deleterious rearrangements. Proc. Natl. Acad. Sci. USA. 1990;87:1551–1555. doi: 10.1073/pnas.87.4.1551. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 23.Cooper D.N., Youssoufian H. The CpG dinucleotides and human genetic disease. Hum. Genet. 1988;78:151–155. doi: 10.1007/BF00278187. [DOI] [PubMed] [Google Scholar]
- 24.Durrington P.N. Hyperlipidaemia: Diagnosis and Management. London: Butterworth & Co. Ltd; 1989. Familial hypercholesterolemia; pp. 91–113. [Google Scholar]
- 25.Scientific Steering Committee on behalf of the Simon Broome Register Group Risk of coronary heart disease in familial hypercholesterolemia. Br. Med. J. 1991;303:893–896. doi: 10.1136/bmj.303.6807.893. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 26.Rubinsztein D.C., Jialal I., Leitersdorf E., Coetzee G.A., Westhuyzen D.R. Identification of two new LDL-receptor mutations causing homozygous familial hypercholesterolemia in a South African of Indian orgin. Biochimica et Biophysica Acta. 1993;1182:75–82. doi: 10.1016/0925-4439(93)90156-u. [DOI] [PubMed] [Google Scholar]
- 27.Kotze M.J., Loubser O., Thiart R., Nico J., Villiers P., Langenhoven E., Theart L., Steyn K., Marais A.D., Raal F.J. CpG hotspot mutations at the LDL receptor locus is a frequent cause of familial hypercholesterolemia among South African Indians. Clin. Genet. 1997;51:394–398. doi: 10.1111/j.1399-0004.1997.tb02497.x. [DOI] [PubMed] [Google Scholar]
- 28.Langenhoven E., Warnich L., Thiart R., Rubinsztein D.C., Westhuyzen D.R., Marais A.D., Kotze M.J. Two novel point mutations causing receptor-negative familial hypercholesterolemia in a South African Indian homozygote. Atherosclerosis. 1996;125:111–119. doi: 10.1016/0021-9150(96)05871-6. [DOI] [PubMed] [Google Scholar]
- 29.Webb T.C., Sun X-M., McCarthy S.N., Neuwirth C., Thompson G.R., Knight B.L., Soutar A.K. Characterization of mutations in the low-density lipoprotein (LDL) receptor gene in patients with homozygous familial hypercholesterolemia, and frequency of these mutations in FH patients in the United Kingdom. J. Lipid. Res. 1996;37:368–381. [PubMed] [Google Scholar]
- 30.Soutar A.K., Knight B.L., Patel D.D. Identification of a point mutation in growth factor repeat of low density lipoprotein receptor gene in a patient with homozygous familial hypercholesterolemia that affects ligand binding and intracellular movement of receptors. Proc. Natl. Acad. Sci., USA. 1989;86:4166–4170. doi: 10.1073/pnas.86.11.4166. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.Ashavaid, T.F., Altaf, A.K., Rao, R. and Nair, K.G. (1997) Molecular basis of familial hypercholesterolemia. Abst. XXIV Ann. Conf. Assoc. Clin. Biochem. India, Calcutta, p. 33. [DOI] [PMC free article] [PubMed]
- 32.Ashavaid T.F., Altaf A.K., Nair K.G., Rao R. Simplified heteroduplex analysis: A rapid method of detecting single-base substitutions in the low-density lipoprotein receptor gene analysis. Abst. San Diego Conference, Nucleic Acid Technologies in Disease Detection. Clin. Chem. 1997;43:2218–2218. [Google Scholar]
- 33.Ashavaid, T.F., Kondkar, A.A., Nair, K.G., Kumar, N. and Krishna, B.A. (1998) Identification of two novel mutations in the low density lipoprotein receptor gene of Indian FH patients. Abst. 8th Asian-Pacific Congress of Clin. Biochem. Malaysia, p. 18.
- 34.Ashavaid T. Two novel LDLR frameshift mutations causing familial hypercholesterolemia. abst IFCC-WorldLab. Firenze, Laboratory Medicine into the next millennium. Clin. chem. Lab. Med. 1999;37(Suppl):117–117. [Google Scholar]
- 35.Ashavaid, T.F., Altaf, A.K. and nair, K.G. (2000) Identification of two LDL-receptor mutations causing familial hypercholesterolemia in Indian subjects by simplified rapid PCR-heteroduplex method. Clin Chem. (In press). [PubMed]
- 36.Innerarity T.L., Mahley R.W., Weisgraber K.H., Bersot T.P., Krauss R.M., Vega G.L., Grundy S.M., Friedl W., Davignon J., McCarthy B.J. Familial defective apolipoprotein B-100: A mutation of apolipoprotein B that causes hypercholesterolemia. J. Lipid. Res. 1990;31:1337–1349. [PubMed] [Google Scholar]
- 37.Miserez A.R., Laager R., Chiodetti N., Keller U. High Prevalence of familial defective apolipoprotein B-100 in Swizterland. J. Lipid. Res. 1994;35:574–583. [PubMed] [Google Scholar]
- 38.Rauh G., Keller C., Kormann B., Spengel F., Schuster H., Wolfram G., Zoller N. Familial defective apolipoprotein B 100: Clinical characteristics of 54 cases. Atherosclerosis. 1992;92:233–241. doi: 10.1016/0021-9150(92)90283-M. [DOI] [PubMed] [Google Scholar]
- 39.Dzau V.J., Morishita R., Gibbons G.H. Gene therapy for cardiovascular disease. Trends in Biotech. 1993;11:205–210. doi: 10.1016/0167-7799(93)90116-Q. [DOI] [PubMed] [Google Scholar]
- 40.Kotze M.J., Theart L., Callis M., Peeters A.V., Thiart R., Langewhoven E. Non radioactive multiplex PCR screening strategy for the simultaneous detection of multiple low-density lipoprotein receptor gene mutations. PCR Methods Applic. 1995;4:352–356. doi: 10.1101/gr.4.6.352. [DOI] [PubMed] [Google Scholar]
- 41.Todur, S.P and Ashavaid, T.F. (2000) Apolipoprotein E gene polymorphism and serum Lp(a) levels: new risk factors for CHD in Indian population. Abst. XXVI Ann. conf. Assoc. Clin. Biochem. India, CMC Vellore, p. 2218.
- 42.Joseph A., Nair K.G., Ashavaid T.F. Angiotensin converting enzyme gene polymorphism in coronary artery disease: The Indian Scenario. Clin. Chem. Lab. Med. 1998;38(8):621–624. doi: 10.1515/CCLM.1998.108. [DOI] [PubMed] [Google Scholar]
- 43.Nair K.G., Ashavaid T.F., Shalia K.K., Dalal J.J. Angiotensin II type I receptor gene A/C1165 polymorphism and coronary artery disease. Abst. 51st Ann. Conf. Cardiol. soc. India, New Delhi. Ind. Heart J. 1999;51:601–601. [Google Scholar]
- 44.Ashavaid T., Nair S., Li S., Nair K.G., Dalal J.J. Hyperhomocysteinemia and the prevalence of methylenetetrahydrofolate reductase mutation in patients with coronary heart disease. Abst. San Diego Conf., Nucleic Acid Technologies in disease Detection. Clin. Chem. 1997;43:2218–2218. [Google Scholar]
