PubMed HealthSearch

PubMed · 9768006

[Genomic imprinting].

Abstract

UNLABELLED: AN EXCEPTION TO THE RULE: For certain genes, alleles are expressed differently depending on whether they originate from the maternal or paternal genome. This is called the parental imprinting. The parental imprinting plays an important role in development and a dysregulation can lead to various disease states. Loss of the parental imprinting or its alteration is implicated in certain genetic diseases and cancers. When the process is altered, two homologous chromosomes may come from the same parent, a situation termed uniparental disomy. GENETIC DISEASE IN MAN: Several genetic diseases in man are known to be related to the parental imprinting. Willi-Prader disease, Angelman disease and Beckwith-Wiedemann disease are the most extensively studied. MECHANISMS: Some of the underlying mechanisms are known, but several points concerning the parental imprinting remain to be elucidated, particularly the precise nature of the molecular mechanisms and the identification of the genes controlling this genetic process.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

G Tachdjian, C Baumann. 1998-02-28. [Genomic imprinting].. https://pubmed.ncbi.nlm.nih.gov/9768006/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Topiramate therapy of epilepsy associated with Angelman's syndrome.

Angelman's syndrome, a genetic disorder involving a defect in the DNA coding for subunits of the gamma-aminobutyric acid (GABA) type A receptor, often is associated with intractable epilepsy. Topiramate is a novel anticonvulsant that enhances GABAergic neurotransmission. Five children with Angelman's syndrome and epilepsy were treated with topiramate for clinical indications. The drug was effective and well tolerated, possibly because of its GABAergic properties. Further studies are necessary to confirm and elucidate this observation.

Angelman Syndrome

Reciprocal inhibitory connections regulate the spatiotemporal properties of intrathalamic oscillations.

Mice with an inactivated GABA(A) receptor beta(3) subunit gene have features of Angelman syndrome, including absence-like seizures. This suggests the occurrence of abnormal hypersynchrony in the thalamocortical system. Within the thalamus, the efficacy of inhibitory synapses between thalamic reticular (RE) neurons is selectively compromised, and thalamic oscillations in vitro are prolonged and lack spatial phase gradients (). Here we used computational models to examine how intra-RE inhibition regulates intrathalamic oscillations. A major effect is an abbreviation of network responses, which is caused by long-lasting intra-RE inhibition that shunts recurrent excitatory input. In addition, differential activation of RE cells desynchronizes network activity. Near the slice center, where many cells are initially activated, there is a resultant high level of intra-RE inhibition. This leads to RE cell burst truncation in the central region and a gradient in the timing of thalamocortical cell activity similar to that observed in vitro. Although RE cell burst durations were shortened by this mechanism, there was very little effect on the times at which RE cells began to burst. The above results depended on widespread stimuli that activated RE cells in regions larger than the diameter of intra-RE connections. By contrast, more focal stimuli could elicit oscillations that lasted several cycles and remained confined to a small region. These results suggest that intra-RE inhibition restricts intrathalamic activity to particular spatiotemporal patterns to allow focal recurrent activity that may be relevant for normal thalamocortical function while preventing widespread synchronization as occurs in seizures.

Angelman Syndrome

The feasibility of PCR-based diagnosis of Prader-Willi and Angelman syndromes using restriction analysis after bisulfite modification of genomic DNA.

We have developed a novel PCR-based method for studying DNA methylation in the proximal region of 15q, using restriction analysis after bisulfite treatment of genomic DNA. This protocol can be used for the diagnosis of Prader-Willi and Angelman syndromes. Unlike the recently reported methylation-specific PCR protocol, our method avoids the use of multiplex amplification, thus overcoming the need to adjust relative primer amounts and the risk of obtaining false-negative results.

Angelman Syndrome