fragile X syndrome

noun
Updated on: 28 Feb 2018

Definition of fragile X syndrome

: an X-linked inherited disorder that is characterized especially by moderate to severe intellectual and developmental disabilities, an elongated face and prominent forehead, chin, and ears, and by large testes in males, and that often has limited or no effect in heterozygous females
  • … most children with fragile X syndrome have other characteristic traits, including anxiety, hyperactivity, and a number of behaviors that are often seen in autism.
  • —Mark Cohen
  • The defective gene responsible for fragile X syndrome is carried on one leg of the X chromosome, the chromosome that helps determine the sex of a child.
  • —Elaine T. Cicora
  • Female carriers of fragile X syndrome as a group exhibit wide variation in degree of phenotypic involvement. Some heterozygotes are cognitively unaffected, others have learning disabilities, and approximately one third have significant mental impairment and an IQ score of less than 85.
  • —Annette K. Taylor, MS, PhD et al.
called also fragile X

First Known Use of fragile x syndrome

1979

in the meaning defined above

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Medical Dictionary

fragile X syndrome

noun \ -ˈeks- \

medical Definition of fragile X syndrome

: an X-linked inherited disorder that is caused by repeats of a trinucleotide sequence on the X chromosome which are abnormal in number and degree of methylation, that is characterized by moderate to severe mental retardation, by large ears, chin, and forehead, and by enlarged testes in males, and that often has limited or no effect in heterozygous females called also fragile X

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