title: Trisomy 18 and neural tube defects.
abstract: BACKGROUND
  Trisomy 18 or Edwards syndrome is a chromosomal abnormality characterized by a broad clinical picture and a limited survival. More than 130 different abnormalities have been described in these patients-among them are neural tube defects.
  
  
  METHODS
  We verified the frequency and types of major neural tube defects observed among patients with trisomy 18. Our sample consisted of consecutive patients evaluated by a clinical genetics service of a referral hospital in southern Brazil between 1975 and 2008. Fisher's exact test (two-tailed) and chi-square test with Yates' correction were used to compare frequencies (P < 0.05 values were considered as significant).
  
  
  RESULTS
  During the period of evaluation, we identified 50 patients with trisomy 18; 33 (66%) were female and age at the first evaluation ranged from 1 day to 16 years (median 14 days). One cell line with full trisomy 18 was the predominant cytogenetic finding (90%). Three patients (6%) had major neural tube defects, all females. These were two patients (4%) with encephaloceles and one (2%) with myelomeningocele. This last patient undergo to correction surgery on her first day of life.
  
  
  CONCLUSIONS
  Our data, in accordance with the literature, support the idea that the presence of neural tube defects among patients with trisomy 18 is not coincidental (i.e., these defects are actually part of the spectrum of abnormalities presented in trisomy 18). Thus, the diagnosis of trisomy 18 should be considered in children with major neural tube defects, especially in the presence of other abnormalities or dysmorphisms.
authors.affiliation: Universidade Federal de Ciências da Saúde de Porto Alegre, RS, Brazil. rfmr@terra.com.br
authors.forename: Rafael Fabiano Machado
authors.initials: RF
authors.lastname: Rosa
authors.forename: Patrícia
authors.initials: P
authors.lastname: Trevisan
authors.forename: Rosana Cardoso Manique
authors.initials: RC
authors.lastname: Rosa
authors.forename: Marina Boff
authors.initials: MB
authors.lastname: Lorenzen
authors.forename: Paulo Ricardo Gazzola
authors.initials: PR
authors.lastname: Zen
authors.forename: Ceres Andréia
authors.initials: CA
authors.lastname: Oliveira
authors.forename: Carla
authors.initials: C
authors.lastname: Graziadio
authors.forename: Giorgio Adriano
authors.initials: GA
authors.lastname: Paskulin
mesh_terms: D000293:Adolescent; D001938:Brazil; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D002887:Chromosomes, Human, Pair 18; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009436:Neural Tube Defects / Q000209:etiology* / Q000235:genetics*; D012189:Retrospective Studies; D014314:Trisomy / Q000503:physiopathology*; D000073842:Trisomy 18 Syndrome