Abstract
Partial duplications involving the long arm of the X chromosome are associated with mental retardation, short stature, microcephaly, hypopituitarism and a wide range of physical findings. We identified an inherited Xq26.2-Xq26.3 duplication in two brothers with severe mental retardation, hypotonia, growth delay, craniofacial disproportion and dental malocclusion. Chromosome analysis was normal and multiplex ligation-dependent probe amplification analysis detected duplication on Xq26. Further characterization by array comparative genomic hybridization and quantitative PCR helped to determine proximal and distal duplication breakpoints giving a size of approximately 2.8 Mb. The duplication encompasses 24 known genes, including the X-linked mental retardation genes ARHGEF6, PHF6, HPRT1 and SLC9A6. Clinical and molecular characterization of Xq duplications will shed more light into the phenotypic implication of functional disomy of X-chromosome genes.
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Acknowledgements
We thank Fundación Ramón Areces (V-2006-FRARECES) and all members of this family for their cooperation. The ‘CIBER de Enfermedades Raras’ is an initiative of the ISCIII. We thank Dr Beatriz Gómez for revising the clinical section of the article.
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Madrigal, I., Fernández-Burriel, M., Rodriguez-Revenga, L. et al. Xq26.2-q26.3 microduplication in two brothers with intellectual disabilities: clinical and molecular characterization. J Hum Genet 55, 822–826 (2010). https://doi.org/10.1038/jhg.2010.119
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DOI: https://doi.org/10.1038/jhg.2010.119
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