Angelman syndrome is a neurogenetic disorder that is characterized by severe intellectual disability, developmental delay, exuberant behavior with a happy demeanor, absent speech, epilepsy, and motor impairment.
It is caused by a deficient UBE3A gene expression which may be due to various abnormalities of chromosome 15.
List Of 17 Interesting Facts About Angelman Syndrome:
#1 In 1965, the syndrome was 1st described in the medical literature by an English physician, called Dr. Harry Angelman. He described the children as “Happy Puppet Children.”
#2 In 1982, two scientists (Frias and Williams) considered the term ”Happy Puppet Children” to be offensive, therefore, the name of the neurogenetic disorder was changed to ”Angelman syndrome.”
#3 In the United States, it affects about 1 in 15,000 people. In Sweden, there is a prevalence of about 1/12,000 in children ages 6 to 13 years.
Causes, Genetics, Chromosome
#4 The most common genetic defect leading to AS is a maternal deletion of DNA from chromosome 15. This leads to an absence of expression of the UBE3A gene in the paternally imprinted brain regions.
Chromosomes, which are present in the nucleus of human cells, transport the genetic information for each individual.
#5 These genetic changes occur as random events in early embryonic development or during the formation of eggs and sperm (reproductive cells).
#6 In a small percentage of cases, AS occurs when an individual inherits 2 copies of chromosome 15 from his or her father instead of one copy from each parent.
#7 People with AS often:
- need less sleep than most people, particularly as children;
- smile and laugh for no apparent reason;
- are excitable and restless;
- speak very little;
- have problems with movement and balance, like – making jerky arm movements, walking with stiff legs, and have difficulty sitting up without support;
- have a delayed development and severe intellectual disability;
- are hyperactive.
#8 Clinical features of the AS do not become manifest until after the first year of life.
#9 Findings in fewer than 80 percent of patients include:
- flat occiput;
- scoliosis (an abnormal sideways curve of the spine);
- occipital groove;
- protruding tongue;
- abnormal food-related behaviors;
- suck/swallowing disorders;
- fascination with crinkly items, like – certain plastics and papers;
- tongue thrusting;
- attraction to/fascination with water;
- diminished need for sleep;
- muscle hypotonia during infancy;
- abnormal sleep-wake cycles;
- increased sensitivity to heat;
- wide-based gait with valgus-positioned ankles;
- widely spaced teeth;
- wide mouth;
- flexed arm position especially during ambulation;
- frequent drooling;
- hyperactive lower-extremity deep-tendon reflexes;
- excessive chewing behaviors;
- light hair and eye color (compared to family);
- strabismus (a condition in which the eyes do not align correctly);
- hypopigmented skin.
#10 Findings in more than 80 percent of patients include:
- abnormal EEG (Electroencephalography – a monitoring method to record the electrical activity of the brain), with a characteristic pattern of large-amplitude slow-spike waves;
- seizures, generally starting before age 3;
- delayed or slow growth in head circumference, typically resulting in relative or absolute microcephaly (a birth defect where a baby’s head is smaller than expected) by age 2.
#11 Findings usually present in affected people:
- behavioral uniqueness, including any combination of often smiling/laughter;
- normal head circumference at birth;
- normal prenatal and birth history;
- balance or movement disorder, typically tremulous movement of the limbs and/or ataxia (a neurological sign consisting of lack of voluntary coordination of muscle movements);
- nonverbal communication skills higher than expressive language skills;
- receptive language skills;
- speech impairment, with minimal to no use of words;
- evidence of developmental delay by age 6 to 12 months;
- delayed attainment of developmental milestones without loss of skills;
- structurally normal brain by CT (Computed Tomography) or MRI (Magnetic Resonance Imaging);
- normal hematologic, metabolic, and chemical laboratory profiles.
#12 Possible complications may include:
- many young children with AS move quickly from one activity to the next and may have short attention spans;
- sleep disorders, like – frequent waking, may require to be treated with behavior therapy or medication;
- feeding difficulties, like – problems swallowing and sucking, may occur during the first year of life.
#13 There are a number of genetic tests that can be done to diagnose the syndrome, such as:
- UBE3A gene (provides instructions for producing ubiquitin protein ligase E3A) mutation analysis – it is used to see if the genetic code on the maternal copy of the UBE3A gene is altered;
- DNA methylation – it is a process by which methyl groups are added to the DNA molecule and shows whether the genetic material on both the father’s and mother’s chromosomes is active;
- fluorescence in situ hybridization (a molecular cytogenetic technique which uses fluorescent probes) – it is used to check the mother’s chromosomes or to check specifically for chromosome 15 deletions when AS is suspected;
- chromosome analysis – to see if any parts of the chromosomes are missing (deletions).
- special education services;
- speech therapy;
- thoracolumbar jackets and/or surgical intervention for scoliosis;
- sedatives for nighttime wakefulness;
- occupational therapy;
- individualization in school settings;
- physical therapy;
- routine management of feeding difficulties;
- antiepileptics for seizures.
#15 Most children with the symptoms will have seizures and will need antiepileptic therapy.
#16 More importantly, they have a higher risk of early death due to aspiration pneumonia (occurs when you inhale stomach acid, food, or saliva into the lungs), seizures, and chronic lung diseases.
#17 Famous people with this syndrome:
- Dave Henderson – he was an American professional baseball player who spent 6 seasons in Oakland, featuring a World Series Championship and 3 consecutive American League Championships. Dave died in December 2015 of a heart attack possibly linked with a recent kidney transplant. He had two sons and was married twice.
- Kit, the son of Ian Rankin (a Scottish crime writer who is best known for his Inspector Rebus novels);
- James, the son of Colin Farrell, an Irish actor who made his film debut in the drama ”The War Zone.”