Abstract
Characteristics of Angelman syndrome (AS) include as with Rett syndrome (RS) developmental delay, lack of speech, seizures, and walking and balance disorders. The prevalence of AS is 1 in 12.00-20.00 population.
It is a classic example of genomic imprinting in that it is usually caused by deletion or inactivation of genes on the maternally inherited chromosome 15. Rett syndrome is a X linked neurodevelopmental disorder that mostly occurs in females.
The condition affects about 1 out of 10 000 girls. Rett syndrome has been found to be caused by mutation in the X-linked gene encoding methyl-CpG-binding protein-2 (MECP2).Most of RS cases arecaused by de novo mutation, and familial cases are rare.