What is trisomy X syndrome?

Trisomy X, also called Triple X syndrome, is caused by the presence of an extra 'X' chromosome, one of the sex chromosomes, in the cells of the body. Signs and symptoms vary between individuals, but are usually mild, if present at all. Individuals with trisomy X may have tall stature, developmental delays, learning disabilities and in some cases difficulty with interpersonal relationships.

How common is trisomy X?

The condition occurs in about one in every 1,000 newborn girls. The condition is not related to race, nationality, religion or socioeconomic status. There is usually no family history of the condition.

How is trisomy X treated?

Treatment depends on what needs the individual has. Girls with trisomy X syndrome may need to be seen by physical, developmental, occupational, or speech therapists if they have developmental or speech problems. Additionally, a pediatric psychologist or group therapy may be helpful if they have social difficulties.

Because many girls with Triple X syndrome are healthy and have a normal appearance, they may remain undiagnosed all their lives, or the diagnosis may be discovered while investigating other medical issues.

Other names for
Trisomy X

  • Triple X syndrome

References

  • Am J Med Genet. 2002 Jun 1:110(1):11-18.
  • Am J Med Genet. 2002 Jun 1;110(1):3-10.
  • Gardner, R. J. M., & Sutherland, G. R. (2011). Chromosome abnormalities and genetic counseling (4th ed.). New York: Oxford University Press, Inc.
  • Jones, K. L. (Ed.). (2013). Smith’s recognizable patterns of human malformation (7th ed.). Philadelphia: Elsevier Inc.