Angelman syndrome

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at April 30, 2016
StartDiseasesAngelman syndrome

A genetic disorder, Angelman syndrome is a lifelong condition that results in developmental disabilities and associated neurological problems. Also known as happy puppet syndrome, Angelman syndrome is characterized by frequent outbursts of laughter and excitability.

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Definition & Facts

The disorder is rare, affecting less than 1 out of every 12,000 to 20,000 people each year in the U.S. People who have the disorder have normal life expectancy. The syndrome was first identified in 1965 by Harry Angelman, a doctor who noticed several children in his medical practice who had protruding tongues, flattened heads, and frequent outbursts of laughter.

People who have Angelman syndrome may have difficulty walking, difficulty balancing, and difficulty speaking, and they may suffer from seizures and have intellectual disabilities and frequently burst in laughter. While there is no cure, people who have the disorder can have normal lifespans, and treatment can help with symptom management.

Symptoms & Complaints

Parents usually recognize that their children have Angelman syndrome around six to twelve months of age. They may first notice that their children are not crawling or making sounds. The children may have smaller than normal head sizes and difficulty with feeding.

Between two and three years of age, many will begin having seizures. Those with the disorder may either have very limited or no speech. Frequent bouts of laughter are common, as is hyperactivity. People may also have flatness in the back of their heads and may walk with their hands lifted up. Some people who have the disorder show other unusual movements, including jerky motions and hand flapping.

Many people with the disorder have thrusting tongues and hypopigmentation of their hair, eyes, and skin. Over time, some people will develop associated problems, including scoliosis, which is abnormal curvature of the spine from side to side, and obesity. Those with Angelman syndrome generally live long lives if they receive appropriate treatment and therapy.

Causes

Angelman syndrome occurs when a person either inherits a UBE3A gene from his or her mother that is damaged or has the maternal copy missing entirely. This gene is located on the 15th chromosome. Genes code different information that a person's cells read and use for proper functioning, and for most gene pairs, cells in the body use some information from each gene in a pair.

In the case of the UBE3A gene pair, however, cells rely only on the information from the maternal copy of the genetic pair; only the maternal copy is active in people's brains. In some cases, the person may instead receive two copies of the gene from his or her father. While Angelman syndrome is a genetic disorder, researchers are unsure of what causes the genetic mutation.

Diagnosis & Tests

When a parent notices developmental delays and makes an appointment with his or her child's physician out of concern that the child has Angelman syndrome, the parent should expect the doctor to first look for the physical signs of the disorder such as head size, head flatness and a protruding tongue.

The doctor may then ask a number of questions, including what signs or symptoms the child exhibits, whether the parent has noticed any problems with feeding and whether the child is meeting the expected developmental milestones. Other questions people might expect include questions about the child's balance, whether or not the child is babbling, whether the child laughs frequently and seems excitable and whether the child has seizures.

The doctor may also ask about unusual movements, lack of speech, sleep problems and if any family member has also been diagnosed with Angelman syndrome. After the initial interview, the doctor may then perform tests in order to confirm the suspected diagnosis.

He or she may perform a blood test, analyzing the child's DNA pattern inherited from his or her parents by using a DNA methylation test. This test looks for three mechanisms that cause Angelman syndrome. Next, diagnosis may include a comparative genomic hybridization test, which looks for missing areas on the chromosomes. If a child has a normal methylation result, the doctor may perform a test called the UBE3A sequencing test, which screens for mutations occurring in active copies of a maternal gene.

Treatment & Therapy

While research is currently being conducted into gene targeting, there is no cure for Angelman syndrome. Treatment for the disorder is focused primarily on symptom management. In most cases, children who have the disorder will receive help from several different medical professionals and therapists. The specific treatment received will depend upon the child's individual symptoms.

Those that have seizures will receive anti-seizure medications to reduce the frequency of the seizures' occurrence. Children may also receive speech therapy and may be taught sign language or how to communicate with others using pictures. Physical therapy is also a common treatment because of the associated motor problems that happen with the disorder.

Some children will receive behavioral therapy to address issues related to excitability and hyperactivity. The team will likely share information. As children grow, they may receive services through a developmental disabilities services provider, and they are likely to have individualized education plans when they reach school age.

Prevention & Prophylaxis

Since there is no known cause for Angelman syndrome, there are no real measures people can take in order to prevent their children from having it. If there is a family history of the disorder, parents may want to carefully watch their children's developmental milestones and take them to their doctors if the disorder is suspected or if delays are observed.

Genetic disorders are not contagious, so there are no prophylactic measures that people need to take to prevent Angelman syndrome from spreading. Parents may want to seek help through support groups in order to better deal with their children's diagnoses.