Net effects of loss of paternal and maternal germline imprints on early mouse development.A, Gross morphology of 9dpc MP, 0P, and 00 embryos. Note that 0P and 00 embryos are very similar in size and phenotype, which implies a minor contribution of paternal imprints to early development. Especially notable signs are the intrauterine growth retardation, open anterior neural tube, enlarged pericardium, reduced head size and abnormal craniofacial features. B., Hyperplasia of the trophoblast giant cell layer (TGC) in 0P and 00 conceptuses. C., Severe deficiency in the vascularization (arrows) of 0P and 00 visceral yolk sacs. Note that erythrocytes are present in MP but are largely absent in 0P and 00 VYS. The parental non-equivalence of imprinting control regions during mammalian development and evolution. Schulz R, Proudhon C, Bestor TH, Woodfine K, Lin CS, Lin SP, Prissette M, Oakey RJ, Bourc'his D - PLoS genetics (2010). Not Altered. CC.
Defective imprinting is deletion of the active allele with inactivated other allele by methylation.
Examples of genomic imprinting include:
Prader-Willi syndrome
Angelman syndrome
The prognosis of Angelman syndrome is fair. People with Angelman syndrome appear to have a reduced but near-normal life expectancy, dying on average 10 to 15 years earlier than the general population.
Prader-Willi syndrome
15q11-15q13 (deletion of paternal allele
Overeating, obesity, decreased muscular tone in infancy, mental retardation, small hands and feet; obesity-related complications can decrease lifespan
