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A 9.6 kilobase deletion in the low density lipoprotein receptor gene in Norwegian familial hypercholesterolemia subjects.

https://arctichealth.org/en/permalink/ahliterature36531
Source
Clin Genet. 1992 Dec;42(6):288-95
Publication Type
Article
Date
Dec-1992
Author
O K Rødningen
O. Røsby
S. Tonstad
L. Ose
K. Berg
T P Leren
Author Affiliation
Department of Medical Genetics, Ullevål Hospital, Oslo, Norway.
Source
Clin Genet. 1992 Dec;42(6):288-95
Date
Dec-1992
Language
English
Publication Type
Article
Keywords
Adolescent
Adult
Aged
Base Sequence
Blotting, Southern
Child
Cholesterol - blood
DNA - analysis
Exons - genetics
Female
Haplotypes
Humans
Hypercholesterolemia, Familial - genetics
Male
Middle Aged
Molecular Sequence Data
Norway
Pedigree
Polymerase Chain Reaction
Polymorphism, Restriction Fragment Length
Receptors, LDL - genetics
Research Support, Non-U.S. Gov't
Sequence Analysis, DNA
Sequence Deletion
Xanthomatosis - etiology
Abstract
Haplotype analysis of the low density lipoprotein receptor (LDLR) gene was performed in Norwegian subjects heterozygous for familial hypercholesterolemia (FH). Southern blot analysis of genomic DNA, using an exon 18 specific probe and the restriction enzyme NcoI, showed that two out of 57 unrelated FH subjects had an abnormal 3.6 kb band. Further analyses revealed that this abnormal band was due to a 9.6 kb deletion that included exons 16 and 17. The 5' deletion breakpoint was after 245 bp of intron 15, and the 3' deletion breakpoint was in exon 18 after nucleotide 3390 of cDNA. Thus, both the membrane-spanning and cytoplasmatic domains of the receptor had been deleted. A polymerase chain reaction (PCR) method was developed to identify this deletion among other Norwegian FH subjects. As a result of this screening one additional subject was found out of 124 subjects screened. Thus, three out of 181 (1.7%) unrelated Norwegian FH subject possessed this deletion. The deletion was found on the same haplotype in the three unrelated subjects, suggesting a common mutagenic event. The deletion is identical to a deletion (FH-Helsinki) that is very common among Finnish FH subjects. However, it is not yet known whether the mutations evolved separately in the two countries.
PubMed ID
1362925 View in PubMed
Less detail

High-degree sequence conservation in LPA kringle IV-type 2 exons and introns.

https://arctichealth.org/en/permalink/ahliterature54419
Source
Clin Genet. 1997 Nov;52(5):293-302
Publication Type
Article
Date
Nov-1997
Author
O. Rösby
P. Aleström
K. Berg
Author Affiliation
Institute of Medical Genetics, University of Oslo, Department of Medical Genetics, Ullevål University Hospital, Norway.
Source
Clin Genet. 1997 Nov;52(5):293-302
Date
Nov-1997
Language
English
Publication Type
Article
Keywords
Conserved Sequence - genetics
Coronary Disease - genetics
Evolution, Molecular
Exons - genetics
Gene Expression Regulation - genetics
Humans
Introns - genetics
Kringles - genetics
Lipoprotein(a) - blood - genetics
Norway
Open Reading Frames - genetics
Plasminogen - genetics
Polymorphism, Genetic - genetics
Repetitive Sequences, Nucleic Acid - genetics
Research Support, Non-U.S. Gov't
Risk factors
Sequence Analysis, DNA
Sequence Homology, Nucleic Acid
Abstract
In the search for factors contributing to the regulation of the Lp(a) lipoprotein concentration, we have sequenced the kringle IV-type 2 encoding exons 1 and 2 together with the flanking intron sequences of the LPA gene in individuals with different serum concentrations of Lp(a) lipoprotein. The high degree of sequence identity between the kringle IV-type 2 repeats made it possible to analyse all the 3-42 kringles simultaneously by polymerase chain reaction and direct DNA sequencing. The strategy used allowed us to determine approximately 700 bp from each kringle IV-type 2 repeat, resulting in a rapid screen of on average 28,000 bp of the LPA gene from each individual. Comparing these bipartite kringle IV-type 2 repeat sequences from 12 individuals with high and 11 individuals with low Lp(a) lipoprotein level revealed that: 1. no sequence polymorphism could be detected in the exons examined; 2. no sequence polymorphism could be detected in the consensus GT/AG splicing signals of exon/intron junctions; and 3. the proximal intron sequences seemed almost completely conserved in the 76-135 bp analysed. Only one position in the intron sequences exhibited the pattern of a G/A polymorphism. We observed no differences between the group with high and the group with low Lp(a) lipoprotein level. The very high conservation of intron sequences could support the hypothesis that the LPA gene evolved relatively recently. The contradictory finding of a corresponding sequence conservation between the human LPA and the plasminogen gene suggests that an evolutionary pressure has preserved these intron sequences over the last 40-90 million years.
PubMed ID
9520119 View in PubMed
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Identification of the apo B-3500 mutation in the Norwegian population.

https://arctichealth.org/en/permalink/ahliterature35323
Source
Scand J Clin Lab Invest. 1995 May;55(3):217-21
Publication Type
Article
Date
May-1995
Author
T P Leren
O K Rødningen
S. Tonstad
O. Røsby
P. Urdal
L. Ose
Author Affiliation
Department of Medical Genetics, Ullevål University Hospital, Oslo, Norway.
Source
Scand J Clin Lab Invest. 1995 May;55(3):217-21
Date
May-1995
Language
English
Publication Type
Article
Keywords
Adult
Apolipoproteins B - genetics
Child
Cholesterol - blood
DNA - analysis
Female
Genes, Dominant
Haplotypes - genetics
Heterozygote
Humans
Hypercholesterolemia, Familial - ethnology - genetics
Male
Norway
Point Mutation
Receptors, LDL - genetics
Research Support, Non-U.S. Gov't
Abstract
Familial defective apolipoprotein B-100 (FDB) is caused by a mutation in codon 3500 of the apo B gene. It is inherited in a co-dominant fashion and is characterized by hypercholesterolaemia. Thus, FDB has similar features to familial hypercholesterolaemia (FH). In order to investigate whether some of the Norwegian subjects diagnosed as having FH actually have FDB, we have screened 208 Norwegian FH heterozygotes for the apo B-3500 mutation. One of the subjects possessed the mutation which was on a haplotype compatible with the mutation-bearing haplotype found in other populations. Although, hypercholesterolaemia segregated with haplotypes both at the apolipoprotein B and low density lipoprotein (LDL) receptor loci in the proband's family, LDL receptor analysis revealed that the proband was not doubly heterozygous for FDB and FH.
PubMed ID
7638555 View in PubMed
Less detail

LPA gene: interaction between the apolipoprotein(a) size ('kringle IV' repeat) polymorphism and a pentanucleotide repeat polymorphism influences Lp(a) lipoprotein level.

https://arctichealth.org/en/permalink/ahliterature199530
Source
J Intern Med. 2000 Jan;247(1):139-52
Publication Type
Article
Date
Jan-2000
Author
O. Røsby
K. Berg
Author Affiliation
Institute of Medical Genetics, University of Oslo, Norway. oddveig.rosby@basalmed.uio.no
Source
J Intern Med. 2000 Jan;247(1):139-52
Date
Jan-2000
Language
English
Publication Type
Article
Keywords
Adult
Alleles
Analysis of Variance
Apolipoproteins - genetics
Apoprotein(a)
Electrophoresis, Gel, Pulsed-Field
Electrophoresis, Polyacrylamide Gel
Female
Genotype
Humans
Kringles - genetics
Lipoprotein(a) - genetics
Male
Norway
Nucleotides - genetics
Polymorphism, Genetic
Reference Values
Abstract
In order to search for factors influencing the Lp(a) lipoprotein level, we have examined the apolipoprotein(a) (apo(a)) size polymorphism as well as a pentanucleotide (TTTTA) repeat polymorphism in the 5' control region of the LPA gene.
Lp(a) lipoprotein levels were compared between individuals with different genotypes as defined by pulsed field gel electrophoresis of DNA plugs, and PCR of DNA samples followed by polyacrylamide gel electrophoresis. DNA plugs and DNA were prepared from blood samples collected from blood donors.
Twenty-seven different K IV repeat alleles were observed in the 71 women and 92 men from which apo(a) size polymorphism results were obtained. Alleles encoding 26-32 Kringle IV repeats were the most frequent. Alleles encoding seven to 11 TTTTA repeats were detected in the 84 women and 122 men included in the pentanucleotide polymorphism study, and homozygosity for eight TTTTA repeats was the most common genotype. The eight TTTTA repeat allele occurred with almost any apo(a) allele. An inverse relationship between number of K IV repeats and Lp(a) concentration was confirmed. The contributions of the apo(a) size polymorphism and the pentanucleotide repeat polymorphism to the interindividual variance of Lp(a) lipoprotein concentrations were 9.7 and 3.5%, respectively (type IV sum of squares). Nineteen per cent of the variance in Lp(a) lipoprotein level appeared to be the result of the multiplication product (interaction) between the apo(a) size polymorphism and the pentanucleotide repeat polymorphism.
The contribution of the apo(a) size polymorphism alone to the variation in Lp(a) lipoprotein level was lower than previously reported. However, the multiplicative interaction effect between the K IV repeat polymorphism and the pentanucleotide repeat polymorphism may be an important factor explaining the variation in Lp(a) lipoprotein levels among the populations.
PubMed ID
10672142 View in PubMed
Less detail

StyI polymorphism in an enhancer region of the second intron of the apolipoprotein B gene in hyper- and hypocholesterolemic subjects.

https://arctichealth.org/en/permalink/ahliterature36558
Source
Clin Genet. 1992 Nov;42(5):217-23
Publication Type
Article
Date
Nov-1992
Author
O. Røsby
R. Poledne
I. Hjermann
S. Tonstad
K. Berg
T P Leren
Author Affiliation
Department of Medical Genetics, Ullevål University Hospital, Oslo, Norway.
Source
Clin Genet. 1992 Nov;42(5):217-23
Date
Nov-1992
Language
English
Publication Type
Article
Keywords
Adult
Aged
Apolipoproteins B - genetics
Base Sequence
Child
Cholesterol - deficiency
Chromosomes, Human, Pair 2
Comparative Study
Czechoslovakia
Deoxyribonucleases, Type II Site-Specific
Enhancer Elements (Genetics) - genetics
Female
Gene Frequency
Genetic markers
Haplotypes
Humans
Hypercholesterolemia - genetics
Introns - genetics
Male
Middle Aged
Molecular Sequence Data
Norway
Point Mutation
Polymerase Chain Reaction
Polymorphism, Restriction Fragment Length
Research Support, Non-U.S. Gov't
Sequence Analysis, DNA
Abstract
The regulation of the human apolipoprotein (apo) B gene that plays a crucial role in lipid metabolism is apparently very complex, with multiple cis- and trans-acting regulatory factors. One of these factors is an enhancer region in the second intron. In this region a point mutation at position + 722 has been found that is detectable by the restriction enzyme StyI. The report of Levy-Wilson et al. (1991) could suggest that the mutant allele (abolished StyI site) is associated with hypocholesterolemia. To investigate further the possible effect of this mutation on plasma cholesterol levels, we have compared the frequency of the mutant allele between 206 hypercholesterolemic Norwegian or Czech subjects on one hand, and 165 hypocholesterolemic Norwegian or Czech subjects on the other hand. No significant difference in frequency was found between the hypercholesterolemic and the hypocholesterolemic groups. This finding indicates either that the mutation at position + 722 does not affect the enhancer activity or that this in vitro enhancer activity is of little or no clinical significance. One of the Norwegian hypercholesterolemic subjects who was of Czech descent possessed the apoB 3500 mutation that leads to defective binding of low density lipoprotein (LDL) to the LDL receptors. Haplotype analysis of the apoB gene in her family showed that the mutation-bearing allele was identical to that reported in other countries, indicating a common gene source.
PubMed ID
1362528 View in PubMed
Less detail