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H Gurling

Publications and source records attributed to H Gurling.

13 recordsLinked to original sources
PubMed1991

No evidence for a susceptibility locus predisposing to manic depression in the region of the dopamine (D2) receptor gene.

Recent reports of cytogenetic abnormalities linked to psychiatric illness and the localisations of the genes for the dopamine (D2) receptor and tyrosinase on the long arm of chromosome 11 have suggested that susceptibility loci for schizophrenia and manic depression might be situated in this region. We could find no evidence for linkage in five Icelandic pedigrees between manic depression and markers in this region, and we have excluded candidate genes coding for the D2 receptor and tyrosinase. We conclude that mutations at loci in this region are not a common cause of manic depression in the population studied.

Adult↗
PubMed1991

Linkage disequilibrium between two highly polymorphic microsatellites.

The PCR was used to amplify genomic DNA from two microsatellite (dC-dA)n.(dG-dT)n sequences found to be present in the same chromosome 5 genomic clone. Analysis of the haplotype frequencies of these two interspersed repeat sequences in individuals showed strong allelic association or linkage disequilibrium. Six alleles were found for p599 (CA)n with a PIC value of 0.71 and 8 alleles were seen for lambda 599 (CA)n with a PIC value of 0.74. The two microsatellites are separated by approximately 7 kb. Analysis of the length variations for the two microsatellites showed that they were positively correlated, a finding that has no obvious explanation. The strong linkage disequilibrium found demonstrates stability during evolution for these novel markers. Therefore they should be powerful new tools for studying genetic drift and admixture of populations. Furthermore, disequilibrium data from microsatellites can be used in the fine mapping and cloning of disease genes.

Alleles↗
PubMed1989

Exclusion of linkage to 5q11-13 in families with schizophrenia and other psychiatric disorders.

Recently a linkage study on five Icelandic and two English pedigrees has provided evidence for a dominant gene for schizophrenia on 5q11-13 (ref. 1). In that study, families with bipolar illness were not included. Using the same probes, two similar but independent investigations on one Swedish pedigree and on fifteen Scottish families excluded linkage to schizophrenia. To evaluate whether the susceptibility gene on 5q11-13 is a common cause of schizophrenia in other populations, we examined five affected North American pedigrees using probes to the D5S39, D5S76 and dihydrofolate reductase loci. Two families in the present series had cases of bipolar disorder. We found that linkage can be excluded by multipoint analysis. These results, taken together, suggest that the disease gene on 5q11-13 does not account for most cases of familial schizophrenia.

Bipolar Disorder↗
PubMed1988

Localization of a susceptibility locus for schizophrenia on chromosome 5.

Schizophrenia is a common disorder with a life time prevalence of approximately 1 per cent. The illness often develops in young adults, who were previously normal, and is characterized by a constellation of symptoms including hallucinations and delusions (psychotic symptoms) and symptoms such as severely inappropriate emotional responses, a disorder of thinking and concentration, erratic behaviour as well as social and occupational deterioration. A considerable proportion of the variance in the liability to develop schizophrenia may be genetic, but segregation analysis, to establish a mode of transmission, has not produced a consistent result. One of these studies was carried out in Iceland and made use of the large family size and extensive geneaological information present in that country. Here we demonstrate genetic linkage of two DNA polymorphisms on the long arm of human chromosome 5 to schizophrenia in seven British and Icelandic families with multiple affected members. The results indicate the existence of a gene locus with a dominant schizophrenia-susceptibility allele. Inheritance of the allele in the families studied suggests that it may also predispose to psychiatric conditions such as schizophrenia spectrum disorders and a variety of other disorders. This report provides the first strong evidence for the involvement of a single gene in the causation of schizophrenia.

Chromosomes, Human, Pair 5↗
PubMed1986

Candidate genes and favoured loci: strategies for molecular genetic research into schizophrenia, manic depression, autism, alcoholism and Alzheimer's disease.

It is argued that further research to achieve more detailed diagnostic systems in many psychiatric disorders is unlikely to be productive without taking genetic effects into account. Even when this is done, for example when carrying out segregation analysis to determine a mode of genetic transmission, mental illnesses often pose specific problems that preclude accurate analysis. Because techniques in molecular biology and genetics have made it possible to study gene effects in human disease systematically it should now be possible to specify the genes that are involved. When this has been achieved then a diagnostic system based on genetic causation can develop. This will have the advantage of helping to pinpoint environmental factors more accurately. Specific strategies will need to be adopted to overcome uncertain modes of inheritance, incomplete or non-penetrance of disease alleles and disease heterogeneity. Highly speculative hypotheses can be put forward for a locus causing Alzheimer's disease on a portion of the long arm of chromosome 21. For autism it is plausible that there is a disease locus at or near the fragile X site on the X chromosome. A locus for manic depression has been very tentatively mapped using DNA markers to chromosome 11 and in a small proportion of families DNA markers have also shown some evidence for X linkage. Schizophrenia does not seem to be associated with any favoured loci. Candidate genes for schizophrenia include those encoding dopamine, other neurotransmitter receptors or enzymes and various neuropeptides such as enkephalin and beta endorphin.

Alcoholism↗
PubMed1985

Application of molecular biology to mental illness. Analysis of genomic DNA and brain mRNA.

Techniques in molecular biology and genetics have made it possible to systematically study gene effects in human disease. The number of gene clusters specifically encoding human brain structure and function is probably about 1,600 or half of all clusters. Evolutionary effects such as linkage disequilibrium and conservation of exons (DNA encoding structural proteins) as well as the fact that there are a tractable number of gene clusters involved, tend to make it quite likely that DNA pathology or DNA variation (polymorphism) predisposing to mental illness can be detected. Genes involved in mental illness can be detected either by studying DNA obtained from blood samples (genomic DNA) directly or by the analysis of mRNA and proteins from suitable cell or tissue preparations. The study of gene expression in the human brain is still in its infancy, nevertheless there are some hints that non-poly-adenylated mRNAs may be important in brain development and certain transcribed sequences may have a specific role in gene expression of the brain. The advantage of studying genomic DNA by the use of linkage and association analysis in multiply affected families is that it will, in the end, almost certainly yield a positive result for a disease with a substantial genetic input. Analysis of gene products from tissues such as brain could in theory detect specific disease genes but the approach will also identify genes secondarily affected by the disease process. Differentiation of genes that are primarily causing mental illness from those that are secondarily affected can be carried out by using such candidate genes as linkage markers in multiply affected families.

Animals↗
PubMedDate not supplied

Molecular genetic evidence for heterogeneity in manic depression.

Manic depression is a severe cyclic mental illness that can be unipolar or bipolar and has a lifetime risk of approximately 7 per 1,000 in most populations. Families with multiple cases of manic depression have been described that are compatible with both autosomal dominant and X-linked modes of genetic transmission. Psychoactive antidepressant and stimulant drugs that help to ameliorate depression and mania are thought to act by affecting catecholamine neurotransmitter systems such as adrenaline, noradrenaline and dopamine, amongst others. Mutations affecting the tyrosine hydroxylase (TH) gene, which encodes the rate-limiting enzyme for the synthesis of these three neurotransmitters, might therefore be responsible for causing the manic depressive phenotype. We have studied three Icelandic kindreds amongst whom it appears that a single autosomal dominant disease allele is segregating. In these families there were 44 cases amongst 73 individuals at risk. Genetic linkage studies were carried out using clones encoding tyrosine hydroxylase the variable portion of the Harvey-ras-1 (HRAS1) locus and the variable region of the insulin gene (INS). All three markers are closely linked on chromosome 11 and were used to observe the segregation of restriction fragment length polymorphisms (RFLPs) in the three affected kindreds. We found no evidence for linkage to these markers in any of the three families. In contrast, Gerhard et al. found linkage between manic depression and HRAS1 in a single large Amish kindred. We conclude that there is genetic heterogeneity of linkage in manic depression. Therefore mutations at different loci are responsible for the manic depressive phenotype in the Amish and in Iceland.

Bipolar Disorder↗