Summary about Disease
Angelman Syndrome (AS) is a complex genetic disorder that primarily affects the nervous system. It's characterized by intellectual disability, developmental delay, speech impairment, movement or balance disorders (ataxia), a happy demeanor with frequent smiling and laughter, and sometimes seizures. Individuals with AS often have a characteristic facial appearance. It is rare and is not a degenerative condition; that is, symptoms do not worsen with age.
Symptoms
Developmental delays, such as not crawling or babbling around 6-12 months
Intellectual disability
Speech impairment: little or no speech
Movement and balance problems (ataxia), such as jerky movements, stiffness, or tremors
Happy, excitable personality, often with frequent smiling, laughter, and hand-flapping
Seizures, usually starting before the age of 3
Small head size (microcephaly)
Fair skin and light hair (though this is less common in some ethnic groups)
Sleep disturbances
Feeding difficulties in infancy
Attention deficit/hyperactivity disorder (ADHD) symptoms
Causes
Angelman Syndrome is typically caused by problems with the UBE3A gene located on chromosome 15. There are several genetic mechanisms that can lead to AS:
Deletion: The most common cause (about 70% of cases) is a deletion of a segment of the maternal chromosome 15 that contains the UBE3A gene.
Uniparental Disomy (UPD): In about 2-5% of cases, a child inherits two copies of chromosome 15 from their father (paternal UPD) instead of one from each parent.
Imprinting Defect: In about 3-5% of cases, the UBE3A gene is present but not turned on (expressed) on the maternal chromosome due to an imprinting defect.
UBE3A Mutation: In approximately 10% of cases, there's a mutation in the UBE3A gene itself on the maternal chromosome.
Unknown Cause: In a significant percentage of cases (around 10-15%), the genetic cause is unknown despite genetic testing. In most cases, Angelman Syndrome is not inherited. It's usually the result of a new genetic change that occurs randomly. However, when the cause is an imprinting defect or a *UBE3A* gene mutation, there is a higher risk of recurrence in future pregnancies.
Medicine Used
There is no cure for Angelman Syndrome, and there are no specific medications to treat the underlying genetic cause. Treatment focuses on managing the symptoms:
Anti-seizure medications: To control seizures. Examples include valproic acid, clonazepam, and lamotrigine.
Muscle relaxants or physical therapy: To address stiffness or movement problems.
Stimulant medications: To manage ADHD symptoms.
Melatonin: To address sleep disturbances.
Laxatives: To manage constipation
Is Communicable
No, Angelman Syndrome is not a communicable disease. It is a genetic disorder and cannot be spread from person to person.
Precautions
Since Angelman Syndrome is a genetic condition, there are no preventative precautions that can be taken during a pregnancy to prevent it. For parents who have a child with AS or have a family history of the condition, genetic counseling and testing can help assess the risk of recurrence in future pregnancies.
Parents with AS child: seek genetic counciling if planning more kids
Parents of AS child: take safety percautions for people with seziures.
How long does an outbreak last?
Angelman Syndrome is not an outbreak of a disease. It is a genetic disorder that is present from birth and is a lifelong condition.
How is it diagnosed?
Angelman Syndrome is usually diagnosed through a combination of clinical evaluation and genetic testing.
Clinical evaluation: Doctors look for the characteristic signs and symptoms of AS, such as developmental delay, movement problems, frequent smiling and laughter, and speech impairment.
Genetic testing: Several genetic tests are used to confirm the diagnosis:
Chromosome analysis: To look for large deletions on chromosome 15.
DNA methylation testing: Also known as Prader-Willi/Angelman Syndrome methylation analysis, this test can detect imprinting defects and uniparental disomy. This is often the first test performed if AS is suspected.
UBE3A sequencing: To identify mutations in the UBE3A gene.
Microarray analysis: To identify small deletions or duplications.
Timeline of Symptoms
The timeline of symptoms can vary, but here's a general guideline:
6-12 months: Developmental delays become apparent, such as not crawling or babbling.
1-3 years: Movement and balance problems (ataxia) develop. Excessive laughter and smiling is common.
Before age 3: Seizures often begin. Speech development is severely delayed or absent.
Childhood: Intellectual disability is evident. Sleep disturbances and feeding difficulties may persist.
Throughout life: Individuals with AS continue to experience intellectual disability, speech impairment, and movement problems.
Important Considerations
Early intervention: Early intervention therapies, such as physical therapy, occupational therapy, speech therapy, and behavioral therapy, can significantly improve the quality of life for individuals with AS.
Seizure management: Seizures can be challenging to control in some individuals with AS, and careful management with anti-seizure medications is essential.
Communication: While speech is often limited, alternative communication methods, such as sign language, picture exchange systems (PECS), or communication devices, can help individuals with AS express themselves.
Safety: Due to balance and coordination problems, safety precautions should be taken to prevent falls and injuries.
Ongoing medical care: Regular medical checkups and monitoring are important to address any health issues that may arise.
Family support: Support groups and organizations for Angelman Syndrome can provide valuable resources and connections for families affected by the condition.
Research: Ongoing research into the causes and treatment of AS offers hope for improved therapies and outcomes in the future.