Angelman syndrome
Overview
Angelman syndrome (AS) is characterised by severe developmental delay or intellectual disability, severe speech impairment, gait ataxia and unique behaviour with an overly happy demeanour that includes frequent laughing, smiling, and excitability. Developmental delays are first noted at around age six months; however, the clinical features of AS do not become apparent until after age one year. Angelman syndrome has multiple causes, all affecting chromosome region 15q11.1-q11.3.
Test type
Genome-wide chromosome microarray (molecular karyotype)
MLPA & Methylation MLPA
Turnaround time
Up to 6 weeks.
Cost
Bulk billed if eligible.
Non Medicare costs below.
Notes
The recommended first tier test for AS is a chromosome microarray. The majority of AS cases (70%) are caused by deletions which can be identified by microarray. This test can be bulk-billed for eligible patients.
If a deletion is not found by microarray testing, methylation analysis can then be requested to exclude paternal uni-parental disomy (UPD) or imprinting centre mutations (accounting for <1% of cases). A second referral is required so the methylation analysis can be bulk-billed for eligible patients.