Analysis of sequence variations in low-density lipoprotein receptor gene among Malaysian patients with familial hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia is a genetic disorder mainly caused by defects in the low-density lipoprotein receptor gene. Few and limited analyses of familial hypercholesterolemia have been performed in Malaysia, and the underlying mutations therefore remain largely unknown.We studied a group of 154 unrelated FH patients from a northern area of Malaysia (Kelantan). The promoter region and exons 2-15 of the LDLR gene were screened by denaturing high-performance liquid chromatography to detect short deletions and nucleotide substitutions, and by multiplex ligation-dependent probe amplification to detect large rearrangements. RESULTS: A total of 29 gene sequence variants were reported in 117(76.0%) of the studied subjects. Eight different mutations (1 large rearrangement, 1 short deletion, 5 missense mutations, and 1 splice site mutation), and 21 variants. Eight gene sequence variants were reported for the first time and they were noticed in familial hypercholesterolemic patients, but not in controls (p.Asp100Asp, p.Asp139His, p.Arg471Gly, c.1705+117 T>G, c.1186+41T>A, 1705+112C>G, Dup exon 12 and p.Trp666ProfsX45). The incidence of the p.Arg471Gly variant was 11%. Patients with pathogenic mutations were younger, had significantly higher incidences of cardiovascular disease, xanthomas, and family history of hyperlipidemia, together with significantly higher total cholesterol and low density lipoprotein levels than patients with non-pathogenic variants. CONCLUSIONS: Twenty-nine gene sequence variants occurred among FH patients; those with predicted pathogenicity were associated with higher incidences of cardiovascular diseases, tendon xanthomas, and higher total and low density lipoprotein levels compared to the rest. These results provide preliminary information on the mutation spectrum of this gene among patients with FH in Malaysia.

Challenges in the Ethical Review of Clinical and Biomedical Research in Malaysia: A Mixed Methods Study.

Empirical evidence of the ethical review of clinical and biomedical research in Malaysia is limited. We have conducted a convergent mixed methods research, which comprises an online survey and semistructured interviews to examine the challenges in the ethical review of clinical and biomedical research. Data collected reveal that the ethics review process is inconsistent, duplicate, and inadequate. The results indicate a strong need for a centralized ethical review mechanism and a national system for mutual recognition of ethics reviews to improve the effectiveness and efficiency of the ethics review system in Malaysia. A joint research ethics committee review between Malaysia and sponsoring countries for multinational research should also be encouraged as it could address the concerns of the lack of expertise and training.

Phenotype-genotype analyses of clinically diagnosed Malaysian familial hypercholestrolemic patients.

BACKGROUND: Familial hypercholesterolemia and familial defective apo lipoprotein B are genetic disorders caused by defects in the low-density lipoprotein receptor gene and apo lipoprotein B 100 genes, respectively. The clinical phenotype of both diseases is characterized by increased plasma levels of total cholesterol and low density lipoprotein cholesterol, tendinous xanthomata, and premature coronary heart disease. OBJECTIVES: The aim of this study is to perform an association study between different gene sequence variants in low-density lipoprotein and apo lipoprotein B 100 genes to the clinical finding and lipid profile parameters of the study subjects. MATERIAL AND METHODS: A group of 164 familial hypercholesterolemic patients were recruited. The promoter region, exon 2-15 of the low density lipoprotein gene and parts of exon 26 and 29 of apo lipoprotein B 100 gene were screened by Denaturating Gradient High Performance Liquid Chromatography. RESULTS: For the apo lipoprotein B 100 gene, those with apo lipoprotein B 100 gene mutation have a significantly higher frequency of cardiovascular disease (P = 0.045), higher low density lipoprotein cholesterol and total cholesterol: high density lipoprotein cholesterol ratio than those without mutation (P = 0.03 and 0.02, respectively). For the low density lipoprotein gene defect those with frame shift mutation group showed the worst clinical presentation in terms of low density lipoprotein cholesterol level and cardiovascular frequency. CONCLUSIONS: There was a statistically significant association between mutations of low density lipoprotein gene and apo lipoprotein B 100 genes and history of cardiovascular disease, younger age of presentation, family history of hyperlipidemia, tendon xanthoma and low density lipoprotein cholesterol level.