Genetic linkage revisited

Article Abstract:

Findings among various researchers differ with regard to a possible link between schizophrenia and an abnormality of a particular chromosome, the cellular structure that contains an individual's unique genetic code. Schizophrenia is a psychotic disorder characterized by a distorted sense of reality and fragmentation of thought and perception. In certain families, it appears to be inherited. The location of a chromosomal abnormality may lead to the discovery of the gene that is associated with the disease and to understanding its cause. The differences in the various studies around this subject and a possible reconciliation of the results are discussed. Two studies show that a trisomy, in which the cell has three homologous chromosomes instead of two, occurred in a number of schizophrenic patients. However, one of the studies included disorders that may not be classified as schizophrenia. Excluding these data, the association may still be valid but additional studies must be carried out. In another study in which no association was found between the chromosome abnormality and schizophrenia, the patients may have had other disorders as well as schizophrenia, obscuring any association with the chromosome. In another study, a link between schizophrenia and the chromosome abnormality was demonstrated, but the association was very weak. Additional studies must be carried out with patients that have schizophrenia and no other disorders to see if this chromosomal abnormality can in fact be associated with schizophrenia.

Causes of, Complications and side effects, Genetic disorders, Trisomy, Schizophrenia

---

Genetic linkage and psychiatric disease

Article Abstract:

This letter about research on genetic linkage of psychiatric diseases was written in response to the article by M. Robertson in Nature, volume 342, page 222, 1989. It is concluded that Robertson gave a clear discussion of the problems that occur when methods that are appropriate for Mendelian disorders are used with disorders that are only rarely inherited in a Mendelian fashion. Mendelian genetics states that each germ cell only receives one gene for each trait and that genes that are not linked will separate independently from one another when being passed on to the germ cells. However, it is felt that Robertson overlooked two related issues. The analysis of a single marker is not sufficient when considering the odds that a particular genetic sequence will be in a particular place on the chromosome. The author also questions whether functional disorders which have such variable manifestations in complicated organs, such as the brain, would have a simple mechanism of disease state. The possibility of more than one predisposing genetic sequence located in different genetic locations is more likely. The more genetic sequences are tested for linkage in a limited number of families, the more likely the possibility that a false linkage will be discovered due to fortuitous segregation. The analysis of the inheritance of genetic markers may lead to erroneous conclusions unless different families are used. (Consumer Summary produced by Reliance Medical Information, Inc.)

Evaluation, Genetic aspects, Mental illness, Mental disorders, Chromosome mapping, Linkage (Genetics), Human chromosomes, letter to the editor

---

Recounting a genetic story

Article Abstract:

The article discusses the importance of research into human chromosome 21 and its impact on the prevention of Down Syndrome conditions.

DNA, Down syndrome

Similar abstracts:

• Abstracts: Insulin resistance and obesity. Mechanisms linking obesity with cardiovascular disease. Mechanisms linking obesity to insulin resistance and type 2 diabetes
• Abstracts: Altered immune responses in mice lacking inducible nitric oxide synthase. Interaction of oestrogen receptor with the regulatory subunit of phosphatidylinositol-3-OH kinase
• Abstracts: Interleukin-1 polymorphisms associated with increased risk of gastric cancer. Structural basis for signal transduction by the Toll/interleukin-1 receptor domains
• Abstracts: Genetic imprinting suggested by maternal heterodisomy in nondeletion Prader-Willi syndrome. Obesity in the new millennium
• Abstracts: Elastic properties of DNA revealed. Reading the minor groove

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.