title: [ARX mutations and mental retardation of unknown etiology: three new cases in Spain].
abstract: BACKGROUND
  Mental retardation has an approximated prevalence of 2% in the general population and its most frequent cause is X-fragile syndrome. This genetic disorder predominantly affects males and it is mainly caused by the expansion of CGG in FMR1 gene. Recently has been demonstrated that mutations in a new called ARX gene (aristaless-related homeobox) can also cause a similar form of X linked mental retardation, as well as other neurological disorders (autism, Partington or West syndrome). The most frequent mutation that has been reported is the c.428_451 dup24, which comprises almost 60% of all described. It causes an expansion of a polyalanine tract of ARX protein.
  
  
  METHODS
  We report three cases of mental retardation in two different families where the mutation in ARX gene c.428_451 dup24 was found while X-fragile syndrome screening was made. Personal and familiar history, phenotype and evolution are described.
  
  
  CONCLUSIONS
  The molecular analysis of this mutation should be considered as a routine for the genetic diagnosis of mental retardation in males of nondrafted cause.
authors.affiliation: Hospital Clínico Universitario, Valencia, España. romerorubio@hotmail.es
authors.forename: M T
authors.initials: MT
authors.lastname: Romero-Rubio
authors.forename: M
authors.initials: M
authors.lastname: Andrés-Celma
authors.forename: M L
authors.initials: ML
authors.lastname: Castelló-Pomares
authors.forename: M
authors.initials: M
authors.lastname: Roselló
authors.forename: I
authors.initials: I
authors.lastname: Ferrer-Bolufer
authors.forename: F
authors.initials: F
authors.lastname: Martínez-Castellano
mesh_terms: D002675:Child, Preschool; D005260:Female; D005600:Fragile X Syndrome / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D007223:Infant; D008297:Male; D038901:X-Linked Intellectual Disability / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics*; D009154:Mutation; D010375:Pedigree; D013030:Spain / Q000453:epidemiology; D014157:Transcription Factors / Q000235:genetics*
chemical_list: C469264:ARX protein, human; D018398:Homeodomain Proteins; D014157:Transcription Factors