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MOLECULAR ANALYSIS:
Angelman Syndrome
Angelman Syndrome (AS) is characterized by severe developmental delay or mental retardation. Patients with AS have severe speech impairment, gait ataxia, and can experience seizures. AS is caused by the absence of the maternal AS region on chromosome 15q11-q13 due to one of several mechanisms. In approximately 70% of cases, AS is caused by a deletion in the maternal 15q11-q13 region. Approximately 5% of cases are caused by paternal uniparental disomy (UPD) of chromosome 15. Imprinting defects in the AS region are responsible for approximately 3% of cases. The remaining 22% of AS cases result from either mutations in the UBE3A gene or from unidentified genetic mechanisms. Deletions, UPD, and imprinting defects lead to abnormal DNA methylation patterns. Analysis for AS is based on detection of the parent specific methylation imprint at chromosome 15q11-13.
- Confirmation of a AS diagnosis in affected individuals
- Individuals with atypical clinical findings
Our laboratory utilizes methylation sensitive polymerase chain reaction (PCR) and gel electrophoresis to detect the parent specific methylation imprint at the AS region on chromosome 15q11-q13.
This assay will detect approximately 78% of patients with AS, including those cases caused by deletions, UPD, and imprinting defects. This assay will not detect approximately 11% of cases due to mutations in the UBE3A gene or approximately 11% of cases due to unidentified genetic mechanisms.
Blood: For children, 3 - 5 cc collected in a purple top (EDTA) or yellow top (acid citrate dextrose) vacutainer tube. For infants, 1 - 2 cc is sufficient. Do not centrifuge or freeze. Sample may be refrigerated or stored at room temperature.
14 days
83890, 83894, 83898, 83912
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