- Severe developmental delay or intellectual disability
- Severe speech impairment
- Gait ataxia and/or tremulousness of the limbs
- Apparent happy demeanor that includes frequent laughing, smiling, and excitability
- Strabismus
- Refractive error
- Deep-set eyes
- Seizures
- EEG shows large amplitude slow-spike waves
- Deletion or defect in 15q11.2-q13 (80%)
- Genes in this area control imprinting of other genes and several genes are imprinted in this area.
- Imprinting leads to methylation or inactivation of certain genes so that material and paternal genes don't both function simultaneously.
- UBE3A mutation (11%)
- Codes for ubiquitin ligase protein
- Ubiquitination is a process of labeling proteins that targets them for degredation
oculoman