Objective: To investigate low density lipoprotein receptor (LDLR) function and gene mutation in Chinese patients with familial hypercholesterolemia(FH).
Methods: Lymphocytes were isolated from 10 ml anticoagulated peripheral blood of the patients, then a flow-cytometric method (FCM) with 1,1'-dioctadecyl-3,3,3', 3-tetramethylindocarbocyanine perchlorate labelled low density lipoproetin (DiI-LDL) was used to identify the function of LDLR on the surface of lymphocytes. Genomic DNA was isolated from whole blood of FH patients and analyzed by PCR-single strand conformation polymorphism (SSCP) and nucleotide sequencing methods.
Results: Defects of binding and uptaking of LDLR were identified by FCM in 2 FH patients in one family, and their parents were examined in the present study. Then they were analyzed genetically. The detected mutation was a deletion of A, which caused a frame shift in codon 297 of exon 6 and introduced a beforehand stop codon in codon 369.
Conclusion: A novel mutation of LDL receptor gene was detected by the combination of FCM and PCR-SSCP methods.