A happy disposition with frequent laughter
A deletion or inactivity on chromosome 15 by array comparative genomic hybridization (aCGH) or by BACs-on-Beads technology.Diagnostic criteria for the disorder were initially established in 1995 in collaboration with the Angelman syndrome Foundation (US); these criteria underwent revision in 2005.Seizures are a consequence, but so is excessive laughter, which is a major hindrance to early diagnosis. Differential diagnosis
Other conditions that can appear similar include:
Autism spectrum
Cerebral palsy
Rett syndrome
Mowat–Wilson syndrome
Adenylosuccinate lyase deficiency
Pitt–Hopkins syndrome
Phelan–McDermid syndrome
Prader–Willi syndrome

Treatment
There is currently no cure available. The epilepsy can be controlled by the use of one or more types of anticonvulsant medications. However, there are difficulties in ascertaining the levels and types of anticonvulsant medications needed to establish control, because people with AS often have multiple types of seizures. Many families use melatonin to promote sleep in a condition which often affects sleep patterns. Many individuals with Angelman syndrome sleep for a maximum of five hours at any one time. Mild laxatives are also used frequently to encourage regular bowel movements. Early intervention with physiotherapy is sometimes used to encourage joint mobility and prevent stiffening of the joints. Speech and Language Therapy is commonly employed to assist individuals with Angelman syndrome and their communication issues.Occupational therapists can contribute to the development and augmentation of non-verbal communication skills by addressing the foundational skills such as finger isolation, motor planning, hand-eye coordination, spatial awareness, and refining gestures.
This is important because individuals with Angelman Syndrome who already possess some form of non-verbal communication have a much harder time adapting to changes in a new or existing AAC device because they can communicate their needs much faster nonverbally.Occupational therapists can assist individuals with Angelman syndrome with many other skills as well. Many individuals with Angelman syndrome also have difficulty processing sensory information and responding appropriately to sensory stimuli. Occupational therapists can work together with these individuals to improve their visual perceptual skills and increase their sensory awareness.Those with the syndrome are generally happy and contented people who like human contact and play. People with AS exhibit a profound desire for personal interaction with others. Communication can be difficult at first, but as a child with AS develops, there is a definite character and ability to make themselves understood. People with AS tend to develop strong non-verbal skills to compensate for their limited use of speech. It is widely accepted that their understanding of communication directed to them is much larger than their ability to return conversation. Most affected people will not develop more than 5–10 words, if any at all. Prognosis
The severity of the symptoms associated with Angelman syndrome varies significantly across the population of those affected. Some speech and a greater degree of self-care are possible among the least profoundly affected. Walking and the use of simple sign language may be beyond the reach of the more profoundly affected.