Some individuals with Angelman Syndrome are misdiagnosed as having autism, pervasive developmental disorder, or cerebral palsy. If an individual fits the diagnostic criteria, testing for AS is recommended as issues, medications, and educational strategies that benefit AS individuals can be drastically different than those recommended for other disorders despite of seemingly similar characteristics.
DNA methylation testing will identify ~ 80% of individuals with Angelman Syndrome including those with deletions, UPD, and imprinting disorders. If the individual is older and fits the criteria, FISH testing for a deletion on Chromosome 15 may be ordered first, but would need to be followed by methylation testing to determine if the deletion is maternal or paternal.
If the FISH and methylation analysis appear normal, sequencing the UBE3A gene directly to identify potential mutations is recommended.
Note that 11% of children that fit the diagnostic criteria for Angelman Syndrome will test normally on all the current available tests. These individuals may have as yet unrecognized mutations that affect UBE3A or genomic imprinting on Chromosome 15. Please note that there are several other syndromes which present like AS that an individual can be tested for.
The genetics behind Angelman Syndrome and what the medical jargon means.