Genotypes of Angelman syndrome
A genotype is the underlying genetic difference that is causing AS. There are 5 genotypes of Angelman syndrome
What does “genotype” mean in Angelman Syndrome?
Angelman syndrome (AS) is caused by a genetic difference that affects the UBE3A gene, resulting in not enough or less functional UBE3A protein in the brain. There are multiple different mechanisms that affect the UBE3A gene and cause the absence or reduction of UBE3A protein. In Angelman syndrome, we call these different genetic mechanisms “genotypes.”
The Angelman syndrome genotypes
Neurotypical*
Deletion (70%)
Mutation (10%)
Uniparental Disomy (UPD) (~5%)
Imprinting Center Defect (ICD) (~2-3%)
Mosaic (1%)
Does your loved one have a clinical diagnosis of AS?
Historically, about 10% of people diagnosed with Angelman syndrome had a “clinical diagnosis”, meaning that even though the person did not have a known genetic difference, that person had enough characteristics of Angelman syndrome that they were considered to have AS. More recently, most individuals with a clinical diagnosis of AS have been found to have a genetic difference in other genes, and actually live with different but similar genetic conditions.
If a loved one has a clinical diagnosis of AS but has not had genetic testing in the past decade (or ever), seeking updated genetic testing may provide clarity. For assistance, reach out to FAST’s genetic counselor at genetic.counselor@cureangelman.org.
Are there clinical trials for individuals living with Angelman syndrome?
