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FISH ANALYSIS:
Angelman Syndrome (FISH Analysis)
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. FISH analysis will identify cases of Angelman Syndrome caused by a deletion of chromosome 15q11-13.
Confirmation of a AS diagnosis in affected individuals
Individuals with atypical clinical findings
FISH analysis for AS is performed on metaphase chromosomes to detect the deletion of chromosome 15q11-13. Chromosomal analysis and FISH is recommended for individuals being tested for AS. For individuals with a normal karyotype, Angelman Syndrome (Methylation Analysis) will detect all cases of AS caused by deletion, UPD, and imprinting defects.
Blood: For adults and children, 3 – 5 cc collected in a sodium heparin (green top) vacutainer tube. For newborns, 2 cc is sufficient. Do not centrifuge or freeze. Store sample at room temperature.
8 days
88230, 88271, 88273, 88291
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