title: [Clinical, genetic and molecular features in 45 patients with Prader-Willi syndrome].
abstract: BACKGROUND
  Prader-Willi syndrome (PWS) is a neurogenetic disease characterized by neonatal hypotonia, retarded mental and motor development, hypogonadism, hyperphagia, morbid obesity and dysmorphic facial features. It has an incidence of 1:12.000-15.000 newborns and is caused by abnormalities in genes located in 15q11q13. PWS is one of the most frequent genetic disorders and microdeletion syndromes. It is also the most common cause of obesity from genetic origin and it was the first disease in which imprinting and uniparental disomy were recognized as cause of genetic disorders. Seventy to seventy five percent of PWS cases are due to 15q11q13 deletions, 20-25% to uniparental disomy and 1% to mutations in the imprinting center.
  
  
  OBJECTIVE
  To analyze the clinical, genetic and molecular features of patients with PWS, seen at one institution.
  
  
  METHODS
  Retrospective review of 45 patients (27 males) with PWS seen at the Genetics Outpatient Clinic at INTA.
  
  
  RESULTS
  Twenty three (51.1%) patients had a deletion, 13 (28.9%) patients did not have a deletion. In nine patients, fluorescence in situ hybridization (FISH) study was not performed, therefore the presence of deletion was unknown. The clinical score was 8 points for patients younger than 3 years (n=11) and 11.5 points for patients older than 3 years (n=34); for patients aged 12 months or less, the clinical score was 7 points. Mean clinical score was 11 points for patients with deletion and 10 points for patients without deletion.
  
  
  CONCLUSIONS
  Most patients with PWS have a deletion; the phenotype depends on age and the clinical score is useful for Chilean patients with PWS.
authors.affiliation: Unidad de Genética y Enfermedades Metabólicas, INTA, Universidad de Chile, Santiago, Chile. fcortes@inta.cl
authors.forename: Fanny
authors.initials: F
authors.lastname: Cortés M
authors.forename: M Angélica
authors.initials: MA
authors.lastname: Alliende R
authors.forename: Andrés
authors.initials: A
authors.lastname: Barrios R
authors.forename: Bianca
authors.initials: B
authors.lastname: Curotto L
authors.forename: Lorena
authors.initials: L
authors.lastname: Santa María V
authors.forename: Ximena
authors.initials: X
authors.lastname: Barraza O
authors.forename: Ledia
authors.initials: L
authors.lastname: Troncoso A
authors.forename: Cecilia
authors.initials: C
authors.lastname: Mellado S
authors.forename: Rosa
authors.initials: R
authors.lastname: Pardo V
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002677:Chile; D005260:Female; D017353:Gene Deletion; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008745:Methylation; D010641:Phenotype; D011218:Prader-Willi Syndrome / Q000175:diagnosis / Q000235:genetics*; D012189:Retrospective Studies