NORD gratefully acknowledges Carole Samango-Sprouse, EdD, Executive Director and Chief Science Officer, The Focus Foundation, for assistance in the preparation of this report.
Trisomy X is a disorder that affects females and is characterized by the presence of an additional X chromosome. Normally, females have two X chromosomes; however, females with trisomy X carry three X chromosomes in the nuclei of body cells. There are specific physical features (phenotype) associated with this chromosomal disorder. Common symptoms that can potentially occur include language-based learning disabilities, developmental dyspraxia, tall stature, low muscle tone (hypotonia), and abnormal bending or curving of the pinkies toward the ring fingers (clinodactyly). Trisomy X occurs randomly as a result from errors during the division of reproductive cells in one of the parents. This disorder occurs in one in 900 to 1,000 live births.
(Please note that some of these organizations may provide information concerning certain conditions potentially associated with this disorder [e.g., learning disabilities].)
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