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.
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.
Angelman syndrome is rare. In most cases, researchers don't know what causes the genetic changes that result in Angelman syndrome. Most people with Angelman syndrome don't have a family history of the disease.
In a small percentage of cases, however, Angelman syndrome may be inherited from a parent, so a family history of the disease may increase a baby's risk of developing Angelman syndrome.
Complications associated with Angelman syndrome include:
- Feeding difficulties. An inability to coordinate sucking and swallowing may cause feeding problems during the infant's early months. Your pediatrician may recommend a high-calorie formula to help your baby gain weight.
- Hyperactivity. Moving quickly from one activity to another, short attention span, and keeping hands or a toy in their mouths may characterize children with Angelman syndrome. Hyperactivity often decreases with age, and medication usually isn't necessary.
- Sleep disorders. People with Angelman syndrome often have abnormal sleep-wake patterns and need less sleep than normal. In some cases, sleep difficulties may improve with age. Medication and behavior therapy may help control sleep disorders.
- Curving of the spine (scoliosis). Some people with Angelman syndrome develop an abnormal side-to-side spinal curvature over time.
- Obesity. Older children with Angelman syndrome tend to have large appetites, which may lead to obesity.
In rare cases, Angelman syndrome may be passed from affected parent to child through defective genes. If you're concerned about a family history of Angelman syndrome, or if you already have a child with Angelman syndrome, consider talking to your doctor or a genetic counselor for help planning future pregnancies.