title: Sirenomelia in Argentina: Prevalence, geographic clusters and temporal trends analysis.
abstract: BACKGROUND
  Sirenomelia is a severe malformation of the lower body characterized by a single medial lower limb and a variable combination of visceral abnormalities. Given that Sirenomelia is a very rare birth defect, epidemiological studies are scarce. The aim of this study is to evaluate prevalence, geographic clusters and time trends of sirenomelia in Argentina, using data from the National Network of Congenital Anomalies of Argentina (RENAC) from November 2009 until December 2014.
  
  
  METHODS
  This is a descriptive study using data from the RENAC, a hospital-based surveillance system for newborns affected with major morphological congenital anomalies. We calculated sirenomelia prevalence throughout the period, searched for geographical clusters, and evaluated time trends.
  
  
  RESULTS
  The prevalence of confirmed cases of sirenomelia throughout the period was 2.35 per 100,000 births. Cluster analysis showed no statistically significant geographical aggregates. Time-trends analysis showed that the prevalence was higher in years 2009 to 2010.
  
  
  CONCLUSIONS
  The observed prevalence was higher than the observed in previous epidemiological studies in other geographic regions. We observed a likely real increase in the initial period of our study. We used strict diagnostic criteria, excluding cases that only had clinical diagnosis of sirenomelia. Therefore, real prevalence could be even higher. This study did not show any geographic clusters. Because etiology of sirenomelia has not yet been established, studies of epidemiological features of this defect may contribute to define its causes. Birth Defects Research (Part A) 106:604-611, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: National Network of Congenital Anomalies of Argentina (RENAC), National Center of Medical Genetics, National Ministry of Health, Buenos Aires, Argentina.
authors.forename: Boris
authors.initials: B
authors.lastname: Groisman
authors.affiliation: National Network of Congenital Anomalies of Argentina (RENAC), National Center of Medical Genetics, National Ministry of Health, Buenos Aires, Argentina.
authors.forename: Rosa
authors.initials: R
authors.lastname: Liascovich
authors.affiliation: Latin American Collaborative Study of Congenital Malformations (ECLAMC-CEMIC), Buenos Aires, Argentina.
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Gili
authors.affiliation: National Network of Congenital Anomalies of Argentina (RENAC), National Center of Medical Genetics, National Ministry of Health, Buenos Aires, Argentina.
authors.forename: Pablo
authors.initials: P
authors.lastname: Barbero
authors.affiliation: National Network of Congenital Anomalies of Argentina (RENAC), National Center of Medical Genetics, National Ministry of Health, Buenos Aires, Argentina.
authors.forename: María Paz
authors.initials: MP
authors.lastname: Bidondo
mesh_terms: D001118:Argentina / Q000453:epidemiology; D004480:Ectromelia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D015995:Prevalence; D012189:Retrospective Studies
keywords: Argentina; geographic clusters; prevalence; sirenomelia; time trends