Angelman syndrome true ICD10CM:Q93.5 OMIM:105830 A syndrome that is characterized by delayed development, intellectual disability, severe speech impairment, and problems with movement and balance. CSP2005:4008-0043 MESH:D017204 happy puppet syndrome disease_ontology DOID:1932 https://www.ilae.org/guidelines/definition-and-classification SNOMEDCT_US_2018_03_01:76880004 Angelman syndrome results from deletion or inactivation of genes on the maternally-inherited chromosome 15q11-q13 region, while the paternal copy, which may be of normal sequence, is imprinted and therefore silenced. The patient has severe intellectual impairment, developmental delay, epilepsy, sleep disorder, jerky movements (especially hand-flapping), ataxia, frequent laughter or smiling, and usually a happy demeanor. Dysmorphic features are well recognized: microcephaly, prominent mandible, pointed chin, protruding tongue, and fair hair and complexion with blue eyes. Seizures are seen in up to 90% and usually start under the age of 2 years, commonly with generalized seizure types (generalized tonic-clonic, atypical absences, myoclonic seizures). Seizures may be aggravated by fever and by certain anti-seizure medications such as carbamazepine and lamotrigine. The EEG is usually very abnormal, and more abnormal than clinically expected. High amplitude 2-3 Hz frontal predominant activity may be seen; symmetrical 4-6 Hz high voltage activity or 3-6 Hz occipital activity overlaid with spikes and sharp waves and associated with eye closure are other patterns that occur. A CGH microarray is usually the most useful diagnostic test. GARD:5810 NCI:C75462 OMIM mapping confirmed by DO. [SN]. UMLS_CUI:C0162635 puppetlike syndrome chromosomal anomaly