Question: What is (are) Angelman syndrome ?
Answer: Angelman syndrome is a genetic disorder that primarily affects the nervous system. Characteristic features of this condition include developmental delay, intellectual disability, severe speech impairment, problems with movement and balance (ataxia), epilepsy, and a small head size. Individuals with Angelman syndrome typically have a happy, excitable demeanor with frequent smiling, laughter, and hand-flapping movements. Many of the characteristic features of Angelman syndrome result from the loss of function of a gene called UBE3A. Most cases of Angelman syndrome are not inherited, although in rare cases a genetic change responsible for Angelman syndrome can be inherited from a parent. Treatment is aimed at addressing each individual's symptoms and may include antiepileptics for seizures; physical, occupational, and speech therapy; and special education services.
Source: GARD

Question: What are the symptoms of Angelman syndrome ?
Answer: What are the signs and symptoms of Angelman syndrome? The Human Phenotype Ontology provides the following list of signs and symptoms for Angelman syndrome. If the information is available, the table below includes how often the symptom is seen in people with this condition. You can use the MedlinePlus Medical Dictionary to look up the definitions for these medical terms. Signs and Symptoms Approximate number of patients (when available) Abnormality of the tongue 90% Behavioral abnormality 90% Broad-based gait 90% Cerebral cortical atrophy 90% Clumsiness 90% Cognitive impairment 90% EEG abnormality 90% Incoordination 90% Mandibular prognathia 90% Muscular hypotonia 90% Neurological speech impairment 90% Seizures 90% Sporadic 75% Abnormality of the teeth 50% Hyperreflexia 50% Malar flattening 50% Wide mouth 50% Hernia of the abdominal wall 7.5% Strabismus 7.5% Absent speech - Autosomal dominant inheritance - Blue irides - Brachycephaly - Constipation - Deeply set eye - Drooling - Exotropia - Fair hair - Feeding difficulties in infancy - Flat occiput - Hyperactivity - Hypopigmentation of the skin - Hypoplasia of the maxilla - Intellectual disability, progressive - Intellectual disability, severe - Limb tremor - Macroglossia - Motor delay - Myopia - Nystagmus - Obesity - Paroxysmal bursts of laughter - Progressive gait ataxia - Protruding tongue - Scoliosis - Sleep-wake cycle disturbance - Widely spaced teeth - The Human Phenotype Ontology (HPO) has collected information on how often a sign or symptom occurs in a condition. Much of this information comes from Orphanet, a European rare disease database. The frequency of a sign or symptom is usually listed as a rough estimate of the percentage of patients who have that feature. The frequency may also be listed as a fraction. The first number of the fraction is how many people had the symptom, and the second number is the total number of people who were examined in one study. For example, a frequency of 25/25 means that in a study of 25 people all patients were found to have that symptom. Because these frequencies are based on a specific study, the fractions may be different if another group of patients are examined. Sometimes, no information on frequency is available. In these cases, the sign or symptom may be rare or common.
Source: GARD

Question: What causes Angelman syndrome ?
Answer: What causes Angelman syndrome? Angelman syndrome is caused by a loss of function of a gene called UBE3A on chromosome 15. The exact mechanism that causes this loss of function is complex. People normally inherit one copy of the UBE3A gene from each parent. Both copies of this gene are turned on (active) in many of the body's tissues. In certain areas of the brain, however, only the copy inherited from a person's mother is active. This parent-specific gene activation is known as genomic imprinting. If the maternal copy of the UBE3A gene is lost because of a chromosomal change or a gene mutation, a person will have no active copies of the gene in some parts of the brain. Several different genetic mechanisms can inactivate or delete the maternal copy of the UBE3A gene. Most cases of Angelman syndrome occur when a segment of the maternal chromosome 15 containing this gene is deleted. In other cases, Angelman syndrome is caused by a mutation in the maternal copy of the UBE3A gene. In a small percentage of cases, a person with Angelman syndrome inherits two copies of chromosome 15 from his or her father, instead of one copy from each parent. This is called paternal uniparental disomy. Rarely, Angelman syndrome can also be caused by a chromosomal rearrangement called a translocation, or by a mutation or other defect in the region of DNA that controls activation of the UBE3A gene. These genetic changes can abnormally turn off (inactivate) UBE3A or other genes on the maternal copy of chromosome 15. The cause of Angelman syndrome is unknown in 10 to 15 percent of affected individuals. Changes involving other genes or chromosomes may be responsible for the condition in these individuals.
Source: GARD

Question: Is Angelman syndrome inherited ?
Answer: How might Angelman syndrome be inherited? Most cases of Angelman syndrome are not inherited, particularly those caused by a deletion in the maternal chromosome 15 or by paternal uniparental disomy. These genetic changes occur as random events during the formation of reproductive cells (eggs and sperm) or in early embryonic development. In these instances, people typically have no history of the disorder in their family. Rarely, a genetic change responsible for Angelman syndrome can be inherited. For example, it is possible for a mutation in the UBE3A gene or in the nearby region of DNA that controls gene activation to be passed from one generation to the next.
Source: GARD