Summary:
Genomic imprinting is one of epigenetic factors, which influences expression of genes. It represents specific marking
of some chromosome segments depending on the parental origin of the mutation. Imprinted genes are for some time
inactive; such period varies in different developmental stage and in different tissues. Such inactivation is manifested
as expriming genes and represents an exception to the 3rd Mendel’s rule. In the last 10 years, a large group of disorders
was recognised, the clinical manifestation of which depends on the parental origin of the mutation, such as Albright’s
hereditary osteodystrophy, progressive osseous hyperplasia, Curschmann-Steinert myotonic dystrophy, Huntington
disease, Beckwith-Wiedemann EMG syndrome, Silver-Russell syndrome, Angelman syndrome, Prader-Willi syndrome.
Genomic imprinting contributes to the clarification of mechanisms of the variable expressivity, incomplete
penetration, generation anticipation etc.
Key words:
genomic imprinting, expriming genes, parental origin of the mutation.
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