Angelman syndrome in Denmark. Birth incidence, genetic findings, and age at diagnosis. Issue 9 (2nd August 2013)

• Record Type: Journal Article
• Authors: Mertz, Line Granild Bie; Christensen, Rikke; Vogel, Ida; Hertz, Jens Michael; Nielsen, Karen Brøndum; Grønskov, Karen; Østergaard, John R.
• Is Part Of: American journal of medical genetics. Volume 161:Issue 9(2013:Sep.)
• Page Start: 2197
• Page End: 2203
• Publication Date: 2013-08-02
• Subjects: Medical genetics -- Periodicals; 616.14205
• DOI: 10.1002/ajmg.a.36058
• Languages: English
• ISSNs: 1552-4825

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>ABSTRACT</title> <sec id="ajmga36058-sec-0001" sec-type="section"> <p>Angelman syndrome (AS) is a neurogenetic disorder caused by loss of expression of the maternal imprinted gene <italic>UBE3A</italic> on chromosome 15q11.2–q13. Clinical features of AS include severe intellectual disability, a happy disposition, ataxia, mandibular prognatism, and epilepsy. Our objectives were to examine the birth incidence of AS in Denmark and to characterize the size of the 15q11.2–q13 deletions with 1, 000K array CGH. In addition, we analyzed genotype differences in regard to age at diagnosis and investigated the occurrence of deletions/duplications outside the 15q11.2–q13 regions. We identified 51 patients with genetically verified AS, which corresponded to a birth incidence of 1:24, 580 (95%CI: 1:23, 727–1:25, 433). Thirty‐six patients showed a deletion; 13 had a Class I deletion and 20 had a Class II deletion. There was bimodal distribution of the BP3 breakpoint. Three patients had larger and atypical deletions, with distal breakpoints telomeric to BP3. Five patients had paternal uniparental disomy (pUPD) of chromosome 15, and four had a verified <italic>UBE3A</italic> mutation. Additional deletions/duplications outside the 15q11.2–q13 areas were demonstrated in half the participants. Six harbored more than one CNV. Mean age at diagnosis was 21 months (95%CI: 17–23 months) for children with a deletion and 46 months (95%CI: 36–55 months) for children with pUPD or a <italic>UBE3A</italic> mutation (<italic>P</italic> < 0.01). The presence of a CNV outside 15q11.2–q13 did not have an impact on age at diagnosis. © 2013 Wiley Periodicals, Inc.</p> </sec> </abstract>