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.
LAM cells generally expand interstitial spaces without violating tissue planes but have been observed to invade the airways, the pulmonary artery, the diaphragm, aorta, and retroperitoneal fat, to destroy bronchial cartilage and arteriolar walls, and to occlude the lumen of pulmonary arterioles.There are two major cell morphologies in the LAM lesion: small spindle-shaped cells and cuboidal epithelioid cells. LAM cells stain positively for smooth muscle actin, vimentin, desmin, and, often, estrogen and progesterone receptors. The cuboidal cells within LAM lesions also react with a monoclonal antibody called HMB-45, developed against the premelanosomal protein gp100, an enzyme in the melanogenesis pathway. This immunohistochemical marker is very useful diagnostically, because other smooth muscle–predominant lesions in the lung do not react with the antibody. The spindle-shaped cells of the LAM lesion are more frequently proliferating cell nuclear antigen positive than the cuboidal cells, consistent with a proliferative phenotype. Compared with cigar-shaped normal smooth muscle cells, spindle-shaped LAM cells contain less abundant cytoplasm and are less eosinophilic. Estrogen and progesterone receptors are also present in LAM lesions, but not in adjacent normal lung tissue. LAM lesions express lymphatic markers LYVE-1, PROX1, podoplanin and VEGFR-3. The smooth muscle–like cells of AMLs are morphologically and immunohistochemically similar to LAM cells, including reactivity with antibodies directed against actin, desmin, vimentin, and HMB-45 as well as estrogen and progesterone receptors. Unlike the dilated airspaces in emphysema, the cystic spaces found in LAM may be partially lined with hyperplastic type II cells.