Angelman syndrome
DEFINITION
Angelman syndrome is a genetic disorder that causes developmental disabilities and neurological problems, such as difficulty speaking, balancing and walking, and, in some cases, seizures. Frequent smiles and outbursts of laughter are common for people with Angelman syndrome, and many have happy, excitable personalities.
Angelman syndrome usually isn’t detected until parents begin to notice developmental delays when a baby is about 6 to 12 months old. Seizures often begin when a child is between 2 and 3 years old.
People with Angelman syndrome tend to live a normal life span. But they may become less excitable and develop sleep problems that may improve with age. Treatment focuses on managing medical and developmental issues.
CAUSES
Angelman syndrome is a genetic disorder, most often caused by problems with a gene located on chromosome 15 called the ubiquitin protein ligase E3A (UBE3A) gene.
A missing or defective gene
- You receive your genes, which occur in pairs, from your parents — one copy from your mother (maternal copy) and the other from your father (paternal copy). Your cells typically use information from both copies, but in a small number of genes, only one copy is active.
- Normally, only the maternal copy of the UBE3A gene is active in the brain. Most cases of Angelman syndrome occur when part of the maternal copy is missing or damaged. In a few cases, Angelman syndrome is caused when two paternal copies of the gene are inherited, instead of one from each parent.
SYMPTOMS
Characteristic Angelman syndrome signs and symptoms include:
- Developmental delays, such as lack of crawling or babbling at 6 to 12 months, and intellectual disability
- Lack of or minimal speech
- Inability to walk, move or balance well (ataxia)
- Frequent smiling and laughter
- Happy, excitable personality
- People who have Angelman syndrome may also have other signs and symptoms, including:
- Seizures, usually beginning between 2 and 3 years of age
- Stiff or jerky movements
- Small head size, with flatness in the back of the head (microbrachycephaly)
- Tongue thrusting
- Light pigmentation in hair, skin and eyes (hypopigmentation)
- Unusual behaviors, such as hand flapping and arms uplifted while walking
When to see a doctor
- Most babies with Angelman syndrome don’t show signs or symptoms of the disorder when they’re born. The first signs of Angelman syndrome are usually developmental delays, such as lack of crawling or babbling, between 6 and 12 months.
- If your child seems to have developmental delays or if your child has other signs or symptoms of Angelman syndrome, make an appointment with your child’s doctor.
