Analysis Of Low Density Lipoprotein Receptor Function & Gene Mutation In Familial Hypercholesterolemic Patients

OBJECTIVE: Familial hypercholesterolemia (FH), caused by various different mutations in the low density lipoprotein (LDL) gene, invariably leads to severe premature coronary heart disease. Heterozygous FH patients are less severely affected but are still at increased risk of CHD. The aim of our research is to analyze the LDL receptor function and gene mutation in FH patients and open an avenue of definite diagnosis toward FH. METHODS: Lymphocytes were isolated from 10ml anticoagulated peripheral blood, then a flow-cytometric method (FCM) with DiI-LDL was used to identify the function of LDL receptor on the surface of lymphocytes. Genomic DNA was isolated from whole blood of FH patients, then analyzed by PCR-SSCP and nucleotide sequencing methods. RESULTS: Defects of internalization of LDL receptors were identified by FCM in all 8 FH patients examined in the present study. 2 FH patients in one family and their parents were analyzed genetically. The detected mutation was a deletion of A, which caused a frameshift in codon 297 of exon 6 and introduced a beforehand stop codon. CONCLUSION: Examining the activity of LDL receptor on the peripheral lymphocytes is an effective artifice for analysis of LDL receptor defects. The PCR-SSCP method is useful to confirm information about the LDL receptor mutation in the molecular level, and is capable about to make earlier diagnosis for the proband in FH family.It is beneficial to other family members by providing genetic consultation.