GTR Home > Conditions/Phenotypes > Trisomy X syndrome

Summary

Triple X syndrome, also called trisomy X or 47,XXX, is characterized by the presence of an additional X chromosome in each of a female's cells. Although females with this condition may be taller than average, this chromosomal change typically causes no unusual physical features. Most females with triple X syndrome have normal sexual development and are able to conceive children.Triple X syndrome is associated with an increased risk of learning disabilities and delayed development of speech and language skills. Delayed development of motor skills (such as sitting and walking), weak muscle tone (hypotonia), and behavioral and emotional difficulties are also possible, but these characteristics vary widely among affected girls and women. Seizures or kidney abnormalities occur in about 10 percent of affected females. [from GHR]

Clinical resources

Practice guidelines

  • ACMG, 2016
  • ESHG/ASHG, 2015
    Non-invasive prenatal testing for aneuploidy and beyond: challenges of responsible innovation in prenatal screening.

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