Linkage analysis in Spanish families with nonspecific X‐linked mental retardation: Significant linkage at Xq13–q21 |
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Authors: | Celia Badenas Sergi Castellví‐Bel Victor Volpini Dolores Jiménez Aurora Sánchez Xavier Estivill Montserrat Milà |
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Institution: | 1. Genetics Service, Hospital Clínic, Barcelona, Spain;2. Medical and Molecular Genetics Centre‐IRO, Hospital Duran i Reynals;3. Barcelona, Spain;4. IDIBAPS (Institut d'Investigacions Biomèdiques August Pi i Sunyer), Barcelona, Spain |
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Abstract: | 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 (χ2 = 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 (χ2 = 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. © 2001 Wiley‐Liss, Inc. |
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Keywords: | mental retardation X chromosome nonspecific mental retardation linkage analysis |
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