title: [Linkage analysis of six Algerian families with autosomal recessive non specific mental retardation].
abstract: BACKGROUND
  Mental retardation is one of the most frequent major handicap, with a 1-3 % frequency in the general population. The recent progress of molecular biology and cytogenetic allowed to identify new genes for non syndromic autosomal recessive mental retardation.
  
  
  OBJECTIVE
  To seek a genetic linkage to the loci implied in the nonspecific mental retardation transmitted into autosomal recessive (ARNSMR) in Algerian families with several affected members and to make the Genetic analysis of ARNSMR for 4 known loci: 3p25-pter; 4q24- q25, 19p13.12 and 1p21.1-p13.
  
  
  METHODS
  The study concerned 34 individuals including 15 patients, belonging to six consanguineous Algerian families. Genotyping was made using polymorphic microsatellite markers and the analysis carried out thanks to the program Gene Mapper software. Statistical analyses were validated using the Fast Link programme of the Easy linkage software (V4:00 betas).
  
  
  RESULTS
  The study carried out made it possible to exclude linkage of all loci for 3 families, nevertheless the linkage of one family to the locus 1p21.1-p13.3 remains possible.
  
  
  CONCLUSIONS
  The absence of linkage of 4 Algerian families with autosomal recessive mental retardation to 3 well known loci, confirms the genetic heterogeneity of mental retardation. We have to pursue research of candidate genes by whole genome scan.
authors.affiliation: Universite Tunis El Manar, Tunisie.
authors.forename: Nadia
authors.initials: N
authors.lastname: Guessibia
authors.forename: Noureddine
authors.initials: N
authors.lastname: Sarrai
authors.forename: Nassima
authors.initials: N
authors.lastname: Methari
authors.forename: Bachir
authors.initials: B
authors.lastname: Ridouh
authors.forename: Habiba
authors.initials: H
authors.lastname: Chaabouni Bouhamed
mesh_terms: D000293:Adolescent; D000328:Adult; D000462:Algeria; D002648:Child; D002869:Chromosome Aberrations; D002878:Chromosomes, Human, Pair 1; D002888:Chromosomes, Human, Pair 19; D002893:Chromosomes, Human, Pair 3; D002894:Chromosomes, Human, Pair 4; D003241:Consanguinity; D005190:Family; D005260:Female; D005808:Genes, Recessive / Q000502:physiology; D008040:Genetic Linkage; D006801:Humans; D008607:Intellectual Disability / Q000235:genetics*; D008297:Male; D010375:Pedigree; D055815:Young Adult