Up to 50% of all patients without molecular confirmation of the other mechanisms causing Angelman syndrome have a mutation in UBE3A, including 75-80% of all familial cases in this category.
Male patients that have clinical features similar to AS that test negative for relevant AS genetic testing, may be considered for mutations in the SLC9A6 gene. SLC9A6 mutations have been identified in male patients with an Angelman-like syndrome phenotype who exhibit features such as developmental delay, mental retardation, seizures and a happy demeanor (X-linked Angelman-like syndrome).
Other disorders that have several overlapping features with AS include Pitt-Hopkins syndrome (caused by mutations of the TCF4 gene) and atypical Rett syndrome (caused by mutations in the MECP2 gene).
Testing for these disorders are available in our laboratory as part of the Angelman syndrome Tier 2 panel or separately and details of these tests can also be found in our information sheets for Pitt-Hopkins and Rett syndrome respectively (see individual test pages for pricing on separate tests).