DETECTING LOW DENSITY LIPOPROTEIN RECEPTOR MUTANT GENE OF RABBIT BY PCR

Objective Watanabe Heritable Hyperlipidaemic (WHHL) rabbits with low density lipoprotein receptor (LDLr) gene mutation have provided unprecedented opportunities for the study of human atherosclerosis, in order to confirm LDL receptor gene status in rabbits, we developed a simple PCR technique to detect LDL mutations in rabbits. Methods Rabbits genomic DNA were extracted from ear biopsy, and amplified by PCR to detect 12bp deletion mutation in WHHL rabbits. PCR products were directly digested with BglⅠ, and then applied to polyacrylamide gel electrophoresis. Results PCR products from homozygous LDLr +/+ rabbits generated 2 bands of 212 and 94bp after BglⅠ digestion, LDLr +/- rabbits generated 3 bands (294, 212, and 94bp), LDLr -/- animals, however, generated only 1 product (294bp). Conclusion This modified PCR method is simple and reliable.

Familial Hypercholesterolemia in an Azorean Family:A Novel Mutation in the Low-Density Lipoprotein Receptor Gene

Familial hypercholesterolemia (FH) is one of the most prevalent autosomal dominant inherited disorders. Mutations have been found in at least 3 genes: the low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), and proprotein convertase subtilisin/kexin type 9 (PCSK9). We report on an Azorean family with FH due to a novel mutation in the LDLR gene across three generations. The index-case was first seen at our endocrinology consultation at 12 years old, because of delayed growth and development. Laboratorial investigations revealed a complete failure of the anterior hypophysis due to a congenital malformation of the sella turcica. A total cholesterol of 313 mg/dL (90 - 190 mg/dL) and low-density lipoprotein cholesterol (LDL-C) of 262 mg/dL (<115 mg/dL) was found in routine blood tests. There was a paternal history of hypercholesterolemia, corneal arcus and myocardial infarction at an early age. Screening for mutations in LDLR gene was carried out. &#73n the affected cases, an intronic heterozygous point mutation (c.818-3C > G) causing a premature termination of transcription (stop codon) was identified.

LDL RECEPTOR RESEARCH IN CHINA

Low density lipoprotein (LDL) receptor is a cell surface glycoprotein that regulates plasma cholesterol by mediating endocytosis of LDL and supplies cells with cholesterol. LDL receptor was first identified in 1973 by Goldstein and Brown, who won the Nobel Prize in 1985. Mutations in the LDL receptor gene cause familial hyper-cholesterolemia (FH), a common disease that affects about 1 in 500 people in most populations. Individuals heterozygous for LDL receptor mutation in one allele express half the normal number of functional receptors on their cell surface. This produces a two-fold elevation in plasma LDL-cholesterol concentration. The excess plasma LDL-cholesterol deposits in tendons and arterial walls, forming tendon xanthomas and atherosclerotic plaques. The rare FH homozygotes (about 1 per million people) have mutations in both LDL receptor genes, express few or no functional LDL receptors on their cell surfaces. Their plasma LDL-cholesterol level rises dramatically and displays a pathognomonic sk

Functional analysis of low-density lipoprotein receptor in homozygous familial hypercholesterolemia patients with novel 1439 C →T mutation of low-density lipoprotein receptor gene

Background Familial hypercholesterolemia （FH）, caused by low density lipoprotein （LDL） receptor （LDL-R） gene mutations, is associated with increased risk of premature coronary heart disease. Until now, limited molecular data concerning FH are available in China. The present study described the clinical profiles and cell biological defects of a Chinese FH kindred with novel LDL-R gene mutation. Methods The patient＇s LDL-R gene coding region was sequenced. The patient＇s lymphocytes were isolated and the LDL-R expression, binding and up-take functions were observed by immunohistochemistry staining and flow cytometry detection. The patient＇s heart and the major large vessels were detected by vessel ultrasound examination and myocardial perfusion imaging （MPI）. Results The patient＇s LDL-R expression, LDL binding and up-take functions were significantly lower than normal control （39%, 63% and 76% respectively）. A novel homozygous 1439 C→T mutation of the LDL-R gene was detected in the patient and his family. ECG showed atypical angina pectoris. Echocardiogram showed stenosis of the coronary artery and calcification of the aortic valve and its root. Blood vessel ultrasound examination showed the thickness of large vessel intima, and the vessel lumen was narrowed by 71%. MPI showed ischemic changes. Conclusions The LDL-R synthesis dysfunction of FH patients leads to arterial stenosis and calcification, which are the major phenotype of the clinical disorder. The mutation of the LDL-R gene is determined. These data increase the mutational spectrum of FH in China.