9 Mb Familial Duplication in Chromosome Band Xp22.2-22.13 Associated with Mental Retardation, Hypotonia and Developmental Delay, Scoliosis, Cardiovascular Problems and Mild Dysmorphic Facial Features

We report on a family with syndromic X-linked mental retardation (XLMR) caused by an Xp22.2-22.13 duplication. This family consists of a carrier mother and daughter and four affected sons, presenting with mental retardation, developmental delay, cardiovascular problems and mild dysmorphic facial features. Female carriers have normal intelligence and some common clinical features, as well as different clinical abnormalities. Cytogenetic analysis of the mother showed an Xp22.2 duplication which was passed to all her offspring. Fluorescence In Situ Hybridization (FISH) using whole chromosome paint and Bacterial Artificial Chromosome (BAC) clones covering Xp22.12-Xp22.3 region, confirmed the X chromosome origin and the size of the duplication. Two different targeted microarray methodologies were used for breakpoint confirmation, resulting in the localization of the duplication to approximately 9.75-18.98 Mb. Detailed description of such rare duplications provides valuable data for the investigation of genetic disease etiology.