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Angelman syndrome is caused by maternal deletions of 15q11-q13, paternal uniparental disomy, imprinting defects, and by mutations in the UBE3A gene. UBE3A encodes the E6-AP ubiquitin ligase protein. This brain-specific imprinted gene demonstrates expression of the maternal allele in the brain, but biallelic expression in other tissues. Mutations in the UBE3A gene account for approximately 5% of all Angelman syndrome cases. Point mutations and small deletions and insertions have been identified in both familial and de novo cases. Diagnostic sequence analysis of the UBE3A coding region is being offered for Angelman syndrome patients who are negative for deletion, paternal UPD or imprinting defects as determined by normal results on the AS methylation testing. Reasons for Referral:
Testing Methodology:PCR amplification of ten exons contained in the UBE3A gene coding region will performed on patient genomic DNA. Direct sequencing of amplification products is performed in both the forward and reverse directions using automated fluorescence dideoxy sequencing methods. Specimen Requirements:Blood: EDTA (purple-top) tubes: Adults: 14
cc; Child: 6
cc Turnaround Time:4 weeks CPT Codes and Prices:A 20% up-front payment is required for the index
case before specimen can be processed. References:
1. Matsuura T, et al. (1997) Nat. Genet. 15: 74-77. Shipping InformationForms: >> Gene
Sequencing Requisition Test Codes:
Index: 6007 |