Linkage analysis in Spanish families with nonspecific X-linked mental retardation: Significant linkage at Xq13-q21

Celia Badenas, Sergi Castellv-Bel, Victor Volpini, Dolores Jimnez, Aurora Snchez, Xavier P. Estivill, Montserrat Mil

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Mental retardation (MR) is a genetically heterogeneous, clinically variable condition. Many cases of MR are linked to the X chromosome. The aim of this study was to identify candidate loci for nonspecific MR in Spanish samples. We selected seven families with nonspecific MR and a pattern of inheritance compatible with an X-linked disorder and a group of 26 sib pairs of mentally retarded individuals. We performed linkage analysis with a panel of 15 markers evenly distributed along the X chromosome. The study showed linkage to marker DXS8076, located in Xq21.1, by the lod score method (z = 2.11 at θ = 0.155) and the nonparametric extended relative pair analysis method (X2 = 5.32; P<0.03). Genetic heterogeneity was found, with an estimated 75% of the families linked at recombination fraction θ = 0.10 to the DXS8076 locus (X2 = 9.51; P < 0.009). Xq13-q21 is one of the critical regions for X-linked MR previously reported, and our study supports the idea that this region may contain a locus for MR in Spanish patients.

Original languageEnglish
Pages (from-to)343-347
Number of pages5
JournalAmerican Journal of Medical Genetics
Issue number4
Publication statusPublished - 1 Feb 2001
Externally publishedYes



  • Linkage analysis
  • Mental retardation
  • Nonspecific mental retardation
  • X chromosome

ASJC Scopus subject areas

  • Genetics(clinical)

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