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L G Jensen

Publications and source records attributed to L G Jensen.

22 records · Page 2Linked to original sources
PubMed1995

Complexity of molecular genetics of dyslipidemia in a family highly susceptible to ischemic heart disease.

In a Danish family highly susceptible to ischemic heart disease, hyperlipidemia did not simply cosegregate with a previously undescribed 10 bp deletion in the LDL receptor gene causing heterozygous familial hypercholesterolemia (FH). This mutation, designated as FH DK-4, deletes 10 nucleotides from exon 4 coding for the third cysteine-rich repeat of the ligand-binding domain. The resulting translational frameshift and stop codon corresponding to amino acid position 181 in the LDL receptor cDNA is predicted to result in a truncated LDL receptor protein. Several family members had hyperlipidemia and early onset of ischemic heart disease not due to the 10 bp deletion, and several family members had unexpectedly high serum lipoprotein(a) contributing to high concentrations of serum LDL cholesterol. The study illustrates important limitations and possibilities of molecular genetic diagnosis.

Base Sequence↗
PubMed1995

Improved RNase protection assay for quantifying LDL-receptor mRNA; estimation of analytical imprecision and biological variance in peripheral blood mononuclear cells.

We have improved the protocol for RNA quantification by using RNase protection. Instead of precipitation and extraction with phenol and chloroform, we use a faster and more reliable precipitation based on guanidinium thiocyanate (GdSCN). The internal standard is produced by in vitro transcription of a DNA template constructed so as to allow simultaneous detection of the in vitro transcript and the low-density lipoprotein receptor (LDLR) mRNA by use of the same probe and hybridization. Addition of this internal standard at the step for RNA isolation reduced the analytical imprecision from 40.8% to 19.3%. Estimates of the within- and between-subject biological variations of the LDLR mRNA content in peripheral blood mononuclear cells (PBMCs) isolated from healthy volunteers were 21.5% and 13.6%, respectively, and the analytical imprecision was 22.6%. The mean content of LDLR mRNA in PBMCs from healthy individuals was 0.78 copies per cell.

Chemical Precipitation↗
PubMed1994

Characterization of a disease-causing Glu119-Lys mutation in the low-density lipoprotein receptor gene in two Danish families with heterozygous familial hypercholesterolemia.

Mutations in the gene for the low-density lipoprotein receptor (LDL receptor) cause the autosomal dominant inherited disease familial hypercholesterolemia (FH). In 15 Danish patients with heterozygous FH we have screened exon 4 of the LDL receptor gene for point mutations and small rearrangements employing genomic DNA amplification and bidirectional solid-phase sequencing. Two subjects were found to be heterozygous for a guanine to adenine base substitution at nucleotide position 418 of the LDL receptor cDNA. This point mutation results in an amino acid change from glutamic acid to lysine at amino acid residue 119 in the third repeat of the cysteine-rich ligand binding domain of the mature LDL receptor. Disruption of LDL receptor function by the Glu119-Lys mutation was confirmed by site-directed mutagenesis and expression in COS-7 cells. By Western blotting the mutation was found to affect the processing of the LDL receptor protein. Using flow cytometric analysis of the transfected cells a decreased binding and internalization of LDL by the mutant receptor was documented. By means of a mutation-specific PCR-based assay the Glu119-Lys mutation was not detected in another 85 apparently unrelated Danish heterozygous FH patients. We identified six persons in the index families with the Glu119-Lys mutation cosegregating with the clinical syndrome of FH in these families. Furthermore, haplotype analysis revealed that the haplotype [SfaNI+, StuI+, AvaII-, (dTA)7] of the mutation carrying allele was the same in the two apparently unrelated patients. This indicates that the mutation has been inherited from a common ancestor.

Adult↗