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Biomedical subjects

A Heiberg

Publications and source records attributed to A Heiberg.

At least 55 records · Page 3Linked to original sources

Linkage relationships of the gene for apolipoprotein CII with loci on chromosome 19.

Two common restriction fragment length polymorphisms detected with cloned gene probes for apolipoprotein CII (apo CII) have been used to study the inheritance of the gene in families segregating for loci on chromosome 19. Lod scores for APOC2 with the gene for complement component 3 (C3) exclude close linkage and give a maximum at a male recombination fraction of 0.25-0.30. Lod scores for APOC2 and FHC, the gene causing familial hypercholesterolaemia, are negative in males and suggest the genes may not be linked. However, it appears that APOC2 may be closely linked to the blood group loci Lutheran (Lu) and Secretor (Se), and probably less closely linked to Lewis (Le). These data are consistent with the gene order: FHC-----C3-----(Lu, Se, APOC2)

Apolipoprotein C-II↗

The use of polymorphic DNA and protein markers for the third complement component for determining linkage of familial hypercholesterolaemia.

We have used DNA and protein polymorphisms for the third complement component (C3) to assess the potential of DNA markers in the diagnosis and study of familial hypercholesterolaemia (FH), and to confirm the reported linkage between FH and C3. The inheritance of FH and the C3 gene has been studied in 10 families by combining information from both the protein and DNA polymorphisms. Our results confirm that the C3 gene is loosely linked to the gene causing FH (lod score maximum of 2.0) at a recombination distance of 0.15. When these results are combined with previously published data the overall lod score maximum is 4.75 at a recombination distance of 0.2, meaning that the two genes will be inherited together in only about 80% of children. These results confirm that the gene that causes familial hypercholesterolaemia is linked to C3 and is therefore on chromosome 19, but C3 is not close enough to be used as a diagnostic marker.

Adolescent↗

Atrioventricular conduction time--a heritable trait?

Routine electrocardiographic tracings (ECGs) were obtained from 491 male and 236 female Norwegians. The atrioventricular conduction time (P-R interval) was read independently on coded ECGs by two physicians. The frequency distributions are presented: mean +/- 2 SD was 0.16 +/- 0.04 s and 0.15 +/- 0.04 s for males and females, respectively. Intra-individual repeatability over 1 year was high, and the measurement error was small. Within each sex, body size, age, heart rate and non-cardiac disease manifestations had little influence on the P-R interval. The P-R interval may be reliably determined in routine ECG tracings by trained observers.

Adult↗

Atrioventricular conduction time--a heritable trait?

The atrioventricular conduction time was studied in 35 adult relatives of six and nine probands with short and long P-R intervals, respectively. A significant difference between the distributions was found. The distribution patterns were compatible with the presence of major genes.

Adult↗

Myofascial pain dysfunction (MPD) syndrome in twins.

The Myofascial Pain Dysfunction Syndrome (MPD) was investigated in 94 twin pairs (21 male pairs and 73 female pairs), who had not been selected with respect to MPD. The frequency of past and/or present symptoms was found to be 10% in males and 27% in females. No differences between monozygous (identical) and dizygous (non-identical) female twins was found in pair-wise concordance rates, the concordance rate being higher than expected to occur by chance in both twin types. The findings are compatible with the view that environmental influences give rise to this specific stress-reaction pattern.

Diseases in Twins↗

Anorexia nervosa--two cases in discordant MZ twins.

Two female monozygous twin pairs discordant for anorexia nervosa are reported, and literature reports on 18 other monozygous pairs are reviewed. Four of the reported pairs are inadequately described and there is doubt about the diagnosis. When the 2 pairs reported here are included, 16 pairs remain: l (38%) were concordant and 10 discordant. Only 3 pairs fulfilled rigorous criteria for anorexia nervosa and zygosity and one of the pairs was concordant. The population prevalence is probably about 2 promille for hospitalized cases, and there is a 6% risk for female sibs of anorectic probands. Hence, if about 1/3 of monozygotic pairs are in fact concordant, a role of genetic factors in the etiology may be suggested.

Adolescent↗

A possible genetic contribution to the alexithymia trait.

Alexithymic characteristics were studied in 15 monozygotic and 18 like-sex dizygotic healthy young twin pairs in a semistructured interview. Variance analysis showed larger within-pair variances in the dizygotic than in the monozygotic twins. With some reservations, these results point to a genetic influence on the etiology of the alexithymic phenomenon.

Analysis of Variance↗

Family similarities in the age at coronary death in familial hypercholesterolaemia.

In a combined Norwegian and British study of the age at death from coronary heart disease of heterozygotes for familial hypercholesterolaemia (FH) the correlation coefficients within families for 43 sib pairs was 0-70 and for 14 first cousin pairs 0-61. There was no significant correlation between the age at death and serum cholesterol concentration in either series. The intrafamilial correlations suggest that information about the age at death from coronary heart disease in heterozygotes within families may have some prognostic value and may also be interpreted as evidence for genetic heterogeneity in FH.

Adult↗

Relationship between sociomedical factors and TMJ-symptoms in Norwegians with myofascial pain-dysfunction syndrome.

The relationship between background characteristics, stress, reported symptoms and clinical findings was studied in a group comprising 333 patients with Myofascial Pain Dysfunction Syndrome (MPD). Three-quarters of this clientele were women, most of them of young or middle age. The stressors most frequently reported were pressed working conditions, anxiety and frustration deriving from disease, and family problems. Of the symptoms, pain was reported by 78 percent of the patients, clicking by 53 percent, limitation of movement by 44 percent and feeling of stiffness and fatigue of masticatory muscles by 41 percent. Significant correlations were found between a number of variables, of which the close relationship between perceived pressors and muscle groups painful to palpation was considered to be a paramount importance. The data were combined into a hypothetic model postulating causal relations. The model was intended for testing and modification in coming studies.

Adolescent↗

Inheritance of xanthomatosis and hyper-beta-lipoproteinaemia. A study of 7 large kindreds.

In a study of xanthomatosis in the county of Ostfold, Norway (approximately 220,000 inhabitants), it was found that 20% (37 out of 185) of the probands belonges to seven large kindreds where xanthomatosis and hyper-beta-lipoproteinaemia segregated. Almost complete ascertainment (99%) of living subjects in the sibships in these families was obtained. Within each kindred, the frequency distribution of age- and sex-adjusted cholesterol and LDL cholesterol were discontinuous; the xanthomatosis patients all had values corresponding to the upper mode, whereas no person without xanthomatosis had such values. The combined results showed a slight overlap. Triglyceride concentrations were unimodally distributed. The genetics of the disorder in the seven families was analysed on the basis of 270 individuals. The segregation pattern satisfied the criteria for autosomal dominant inheritance, but not those for a polygenic trait. Thus, xanthomatosis with hyper-beta-lipoproteinaemia segregates as an autosomal dominant trait in these seven kindreds. No evidence of reduced penetrance was found. Since both IIA and IIB lipoprotein patterns were observed within the same family, there is no evidence that the two patterns reflect the presence of different genes in these kindreds.

Adolescent↗

The inheritance of hyperlipoproteinaemia with xanthomatosis. A study of 132 kindreds.

In a study of xanthomatosis kindreds in the county of Ostfold, Norway, 95 % of the living first degree relatives of the probands were investigated. Hyperlipoproteinaemia (lipid values above the 95th percentile) was present in 40.8 % of 554 first degree relatives of probands with xanthomatosis. The distribution curve was bimodal for cholesterol and LDL cholesterol concentrations, but not for triglyceride concentration within the different categories of families. The IIA lipoprotein pattern was the most frequent lipoprotein abnormality, in probands as well as in affected first degree relatives. However, IIB and IV lipoprotein patterns were also found in affected family members, irrespective of the pattern in the probands. About 93% of the xanthomatosis subjects had a lipoprotein disorder segregating as an autosomal dominant; the remaining 7 % were sporadic cases and/or had a multifactorially determined xanthomatosis. More sibs that offspring were affected; this was particularly pronounced for males with a IIA lipoprotein pattern. The genetic analysis gave no reason to suspect that hypercholesterolaemia with a IIA pattern is not the same disease as hypercholesterolaemia with a IIB pattern. However, a significant number of xanthomatosis patients had more than one type of hyperlipoproteinaemia. The frequency of the xanthomatosis trait was estimated to be 3.2/1000, and the ascertainment probability 0.6. The prevalence of familial hypercholesterolaemia with xanthomatosis was estimated to be 2.2/1000 and the multiple type hyperlipoproteinaemia with xanthomatosis had a frequency of 1.0/1000.

Chromosome Aberrations↗