title: [Frequency of holoprosencephaly in Chile].
abstract: BACKGROUND
  Holoprosencephaly is a structural anomaly of the brain that consists in a defect of the prosencephalon development that leads to face and neurological defects of variable intensity.
  
  
  OBJECTIVE
  To estimate holoprosencephaly prevalence at birth.
  
  
  METHODS
  All cases of holoprosencephaly, born alive or stillbirths, registered in the 15 Chilean Hospitals of the Latin American Collaborative Study of Congenital Malformations (ECLAMC) between 1972 and 2012, were studied. Craniofacial and other anomalies found in newborns affected by holoprosencephaly are described.
  
  
  RESULTS
  Fifty five cases of holoprosencephaly (58% males) were found among the 798.222 registered births (rendering a prevalence at birth of 0.69 per 10.000 newborns). The most common cranial defect was medial cleft lip with cleft palate (27.3%), bilateral cleft lip (11%) or both (38.2%), cyclopia (14%), single nostril (10.9%) and proboscis (9.1%). Eleven percent cases had a trisomy 13. A slight increase in prevalence over time was observed.
  
  
  CONCLUSIONS
  Holoprosencephaly has a low frequency in Chile and is associated to trisomy 13. The increase in prevalence could be explained by a better prenatal diagnosis (ultrasonography).
authors.forename: Julio
authors.initials: J
authors.lastname: Nazer Herrera
authors.forename: Lucía
authors.initials: L
authors.lastname: Cifuentes Ovalle
authors.forename: Andrea
authors.initials: A
authors.lastname: Cortez López
mesh_terms: D000293:Adolescent; D000328:Adult; D002677:Chile / Q000453:epidemiology; D002971:Cleft Lip / Q000453:epidemiology / Q000209:etiology; D002972:Cleft Palate / Q000453:epidemiology / Q000209:etiology; D005260:Female; D016142:Holoprosencephaly / Q000145:classification / Q000150:complications / Q000453:epidemiology*; D006801:Humans; D050498:Live Birth; D008297:Male; D008423:Maternal Age; D015995:Prevalence; D012737:Sex Factors; D050497:Stillbirth; D055815:Young Adult