DISEASE INFORMATION
Angelman syndrome (AS) is an autosomal dominant disorder characterized by severe developmental delay accompanied by severe speech impairment, gait ataxia or tremulousness of limbs, unique behavior that include a happy demeanor with frequent or inappropriate laughter, hyperactivity and social-seeking behavior. The prevalence of AS varies from one in 15,000-40,000.^1,2 AS patients usually have normal prenatal history, fetal development, birth weight and head circumference at birth. Developmental delay starts at the age of six months, but symptoms specific to AS do not present until after one year of life. There is no cure for AS, but disease management is targeted to the prevention or control of seizures, behavior modifications, physical therapy and making the life of patients more comfortable. The life expectancy of individuals with AS is comparable to non-affected individuals.^3,4

TESTING BENEFITS & INDICATIONS
• Diagnostic testing is indicated for individuals known or suspected to have clinical features associated with Angelman    syndrome. Molecular testing to determine the underlying genetic mechanism can aid in accurate risk assessment.   
• Maternal testing should be considered when a mutation in UBE3A has been identified in a proband to determine if the    mutation is de novo or inherited and for accurate risk assessment.
• Prenatal diagnosis may be considered in families with a previous history of Angelman syndrome.

TEST DESCRIPTION
The Ambry SEQUENCE: Angelman Syndrome, consist of methylation analysis of the SNRPN gene, and if negative is relex to UBE3A gene sequence analsysis. Each step is also offered individually. The Ambry Test: UBE3A-Related Angelman Syndrome consists of gene sequence analysis performed by PCR-based double-stranded automated sequencing in the sense and antisense directions for exons 7-16 of the UBE3A gene, plus at least 20 bases into the 5’ and 3’ ends of all the introns. Specific mutation analysis for individual UBE3A mutations known to be in the family is also available. The Ambry Test: Prader-Willi/Angelman Syndrome Methylation Analysis (15q11-q13 deletion) is performed by PCR to selectively amplify regions of gDNA corresponding to exon 1 and the putative promoter of the SNRPN gene followed by single-stranded sequencing on a pyrosequencing platform (Pyromark MD). Detecting the methylation pattern within the 15q11.2-13 locus allows for the discrimination between the maternal (methylated) and paternal (unmethylated) alleles. A total of 12 CpG dinucleotide sequences are analyzed for methylation status.

MUTATION DETECTION RATE
Methylation analysis of the SNRPN gene is capable of detecting deletions, UPD, and imprinting defects which cause >72% of Angelman syndrome. Gene sequence analysis of the UBE3A geneis capable of detecting >99% of described mutations in the UBE3A gene, which account for 10-11% of Angelman syndrome. The Ambry SEQUENCE, which combines methylation analysis and gene sequence analysis, can detect over 82% of known defects causing Angelman syndrome.

SPECIMEN REQUIREMENTS
Blood: Collect 3-5 cc from adult or 2 cc minimum from child into EDTA purple-top tube (first choice) or ACD yellow-top tube (second choice).  Store at room temperature or refrigerate. Ship at room temperature.
Saliva: Collect 2 ml into Oragene™ DNA Self-Collection container. Store and ship at room temperature. 
DNA: Send 20 µg in TE at 50-100 ng/µl. Store frozen and ship on ice or dry ice.
Prenatal: Prenatal testing is available. Please call an Ambry Genetic Counselor to discuss your case.

REFERENCES
¹ Stromme P. Dev Med Child Neurol. 2000; 42(2): 76-86.
² Thomson AK et al. Disabil Rehabil. 2006; 28(5): 299-305.
³ Clayton-Smith J & Lann L. J Med Genet. 2003;40:87-95.
⁴ Van Buggenhout G & Fryns JP. Eur J Hum Genet advance online publication, 20 May 2009; doi:10.1038/ejhg.2009.67.
⁵ Williams CA et al. Angelman syndrome. 5 Sep 2008. GeneReviews,    http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=angelman. Accessed August 24 2009.   
⁶ Jiang Y et al. Am J Hum Genet. 1999;65:1-6.
⁷ Stalker HJ & Williams CA. Am J Med Genet. 1998;77(1):54-59.

DISCLAIMER
This test was developed and its performance characteristics were determined by Ambry Genetics Corporation.  The laboratory is regulated under the Clinical Laboratory Improvement Amendments 2003 as qualified to perform nonwaived testing.  The Ambry Test: UBE3A-Related Angelman Syndrome analyzes the following types of mutations: nucleotide substitutions, small deletions, small insertions (including small repeat expansion) and small indels. The Ambry Test: Prader-Willi/Angelman Syndrome Methylation Analysis (15q11-q13 deletion) analyzes the following types of mutations: 15q11-q13 gross deletions, including uniparental disomy of chr. 15q11-q13.  These tests are not intended to analyze the following types of mutations: gross insertions, gross rearrangements, deep intronic variations, and other unknown abnormalities.  The pattern of mutation types varies with the gene tested and the Ambry Test detects a high but variable percentage of known and unknown mutants of the classes stated.  A negative result from the analysis cannot rule out the possibility that the tested individual carries a rare unexamined mutation or mutation in the undetectable group. The Ambry Test: UBE3A-Related Angelman Syndrome is designed and validated to be capable of detecting >99% of described mutations in UBE3A (considering less than 1% to be the other types of mutations). Angelman Syndrome is a complex clinical disorder, in which ~10-11% of cases are due to alterations in UBE3A generally detected by the Ambry Test: UBE3A-Related Angelman Syndrome except as noted above. The Ambry Test: Prader-Willi/Angelman Syndrome Methylation Analysis (15q11-q13 deletion) is designed and validated to be capable of detecting >72% of described mutations that cause Angelman syndrome. The Ambry SEQUENCE: Angelman Syndrome which includes methylation analysis of the SNPRN gene and UBE3A gene sequence analysis, is designed and validated to be capable of detecting >82% of described mutations that cause Angelman syndrome. Mutations in other genes or the regions not tested by the Ambry SEQUENCE: Angelman Syndrome can also give rise to clinical conditions similar to Angelman Syndrome.  Although molecular tests are highly accurate, rare diagnostic errors may occur.  Possible diagnostic errors include sample mix-up, erroneous paternity identification, technical errors, clerical errors, and genotyping errors. Genotyping errors can result from trace contamination of PCR reactions, from maternal cell contamination in fetal samples, from rare genetic variants, which interfere with analysis, or from other sources. This report does not represent medical advice.  Any questions, suggestions, or concerns regarding interpretation of results should be forwarded to a genetic counselor, medical geneticist, or physician skilled in interpretation of the relevant medical literature.  References are available upon request.