Xp11.2 duplication

Region of Xp11.2 duplications.

Xp11.2 duplication is a genomic variation marked by the duplication of an X chromosome region on the short arm p at position 11.2, defined by standard karyotyping (G-banding). This gene-rich, rearrangement prone region can be further divided into three loci - Xp11.21, Xp11.22 and Xp11.23. The duplication could involve any combination of these three loci. While the length of the duplication can vary from 0.5Mb to 55 Mb, most duplications measure about 4.5Mb and typically occur in the region of 11.22-11.23.[1] Most affected females show preferential activation of the duplicated X chromosome.[2] Features of affected individuals vary significantly, even among members of the same family. The Xp11.2 duplication can be 'silent' - presenting no obvious symptoms in carriers - which is known from the asymptomatic parents of affected children carrying the duplication.[3][4] The common symptoms include intellectual disabilities, speech delay and learning difficulties, while in rare cases, children have seizures and a recognizable brain wave pattern when assessed by EEG (electroencephalography).

  1. ^ "Unique The Rare Chromosome Disorder Support Group". www.rarechromo.org. Retrieved 2018-02-28.
  2. ^ "Microduplication Xp11.22-p11.23 syndrome | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program". rarediseases.info.nih.gov. Retrieved 2018-02-28.
  3. ^ Giorda R, Bonaglia MC, Beri S, Fichera M, Novara F, Magini P, et al. (September 2009). "Complex segmental duplications mediate a recurrent dup(X)(p11.22-p11.23) associated with mental retardation, speech delay, and EEG anomalies in males and females". American Journal of Human Genetics. 85 (3): 394–400. doi:10.1016/j.ajhg.2009.08.001. PMC 2771536. PMID 19716111.
  4. ^ Honda S, Hayashi S, Imoto I, Toyama J, Okazawa H, Nakagawa E, Goto Y, Inazawa J (September 2010). "Copy-number variations on the X chromosome in Japanese patients with mental retardation detected by array-based comparative genomic hybridization analysis". Journal of Human Genetics. 55 (9): 590–9. doi:10.1038/jhg.2010.74. PMID 20613765.