title: Detection of deletions at 7q11.23 in Williams-Beuren syndrome by polymorphic markers.
abstract: BACKGROUND
  Williams-Beuren syndrome (WBS; OMIM 194050) is caused by a hemizygous contiguous gene microdeletion at 7q11.23. Supravalvular aortic stenosis, mental retardation, overfriendliness, and ocular and renal abnormalities comprise typical symptoms in WBS. Although fluorescence in situ hybridization is widely used for diagnostic confirmation, microsatellite DNA markers are considered highly informative and easily manageable.
  
  
  OBJECTIVE
  This study aimed to test the microsatellite markers for the diagnosis of Williams-Beuren syndrome, to determine the size and parental origin of microdeletion, compare the clinical characteristics between patients with different sizes of the deletion and parental origin.
  
  
  METHODS
  We studied 97 patients with clinical diagnosis of Williams-Beuren syndrome using five microsatellite markers: D7S1870, D7S489, D7S613, D7S2476 and D7S489_A.
  
  
  CONCLUSIONS
  Using five markers together, the result was informative in all patients. The most informative marker was D7S1870 (78.4%), followed by D7S613 (75.3%), D7S489 (70.1%) and D7S2476 (62.9%). The microdeletion was present in 84 (86.6%) patients and absent in 13 (13.4%) patients. Maternal deletions were found in 52.4% of patients and paternal deletions in 47.6% of patients. The observed size of deletions was 1.55 Mb in 76/ 84 patients (90.5%) and 1.84 Mb in 8/84 patients (9.5%). SVAS as well as ocular and urinary abnormalities were more frequent in the patients with a deletion. There were no clinical differences in relation to either the size or parental origin of the deletion.
  
  
  CONCLUSIONS
  Using these five selected microsatellite markers was informative in all patients, thus can be considered an alternative method for molecular diagnosis in Williams-Beuren syndrome.
authors.affiliation: Instituto da Criança, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brazil. roberta.dutra@icr.usp.br
authors.forename: Roberta Lelis
authors.initials: RL
authors.lastname: Dutra
authors.forename: Patrícia de Campos
authors.initials: Pde C
authors.lastname: Pieri
authors.forename: Ana Carolina Dias
authors.initials: AC
authors.lastname: Teixeira
authors.forename: Rachel Sayuri
authors.initials: RS
authors.lastname: Honjo
authors.forename: Debora Romeo
authors.initials: DR
authors.lastname: Bertola
authors.forename: Chong Ae
authors.initials: CA
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002897:Chromosomes, Human, Pair 7 / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D056726:Genetic Association Studies; D005819:Genetic Markers; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D008297:Male; D018895:Microsatellite Repeats; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D015203:Reproducibility of Results; D018980:Williams Syndrome / Q000175:diagnosis / Q000235:genetics*
chemical_list: D005819:Genetic Markers