title: Consanguineous unions and the burden of disability: a population-based study in communities of Northeastern Brazil.
abstract: OBJECTIVE
  The aim of this study was to identify communities at high risk of transmitting recessive genetic disorders by measuring levels of endogamy and offspring's rate of disabilities.
  
  
  METHODS
  In a house-to-house population based-survey in the state of Paraíba, 20,462 couples were interviewed regarding kinship relation, number of siblings and offspring affected by mental or physical disabilities.
  
  
  RESULTS
  The rate of consanguineous unions in the communities ranged from 6.0% to 41.14%, showing an average value of 20.19% ± 9.13%. The overall average inbreeding coefficient (F) was 0.00602 ± 0.00253, ranging from 0.00134 to 0.01182. Communities situated on the backlands had an increased average value of F compared to those closer to the seashore (P = 0.024). The average rate of disabled offspring varied from 2.96% ± 0.68% for unrelated unions to 10.44% ± 16.86% for related couples at the level of double first cousins or uncle-niece. The Spearman correlation coefficient between the overall rate of disabled offspring from all couples together and F was 0.510 (P < 0.01).
  
  
  CONCLUSIONS
  Inbreeding increases the risk of disability which is unevenly distributed, varying considerably even in neighboring communities with similar Human Development Index and population density. Higher inbreeding communities are mostly located on the more economically underdeveloped backlands than on the coastal region. The identification of communities at high risk for genetic disorders could serve as basis for the establishment of Community Genetics programs.
authors.affiliation: Department of Biology, Centre for Community Genetic Research, Universidade Estadual da Paraíba, Campina Grande, Paraíba, Brazil.
authors.forename: Mathias
authors.initials: M
authors.lastname: Weller
authors.forename: Marina
authors.initials: M
authors.lastname: Tanieri
authors.forename: Josecleide Calixto
authors.initials: JC
authors.lastname: Pereira
authors.forename: Ednno Dos Santos
authors.initials: Edos S
authors.lastname: Almeida
authors.forename: Fernando
authors.initials: F
authors.lastname: Kok
authors.forename: Silvana
authors.initials: S
authors.lastname: Santos
mesh_terms: D001938:Brazil / Q000453:epidemiology; D000013:Congenital Abnormalities / Q000453:epidemiology* / Q000235:genetics; D003241:Consanguinity; D006233:Persons with Disabilities / Q000706:statistics & numerical data; D005195:Family Relations; D005260:Female; D005808:Genes, Recessive; D006801:Humans; D008297:Male; D008393:Marriage / Q000706:statistics & numerical data