When the abnormality is on pair #23, the result is a sex-linked chromosomal abnormality. A person might have XXY, XYY, XXX, XO, or 45 or 47 chromosomes as a result. Two of the more common sex-linked chromosomal disorders are Turner’s syndrome and Klinefelter’s syndrome. Turner’s syndrome occurs in 1 of every 2,500 live female births (Carroll, 2007) when an ovum which lacks a chromosome is fertilized by a sperm with an X chromosome. The resulting zygote has an XO composition. Fertilization by a Y sperm is not viable. Turner syndrome affects cognitive functioning and sexual maturation. The external genitalia appear normal, but breasts and ovaries do not develop fully and the woman does not menstruate. Turner’s syndrome also results in short stature and other physical characteristics.  Learn more at www.turnersyndrome.org/. Klinefelter’s syndrome (XXY) occurs in 1 out of 700 live male births and results when an ovum containing an extra X chromosome is fertilized by a Y sperm. The Y chromosome stimulates the growth of male genitalia, but the additional X chromosome inhibits this development. An individual with Klinefelter’s syndrome has some breast development, infertility (this is the most common cause of infertility in males), and has low levels of testosterone.

Most of the known genetic disorders are dominant gene-linked; however, the vast majority of dominant gene linked disorders are not serious disorders, or if they are, they may still not be debilitating. For example, the majority of those with Tourette’s Syndrome suffer only minor tics from time to time and can easily control or cover up their symptoms. Huntington’s Disease is a dominant gene linked disorder that affects the nervous system and is fatal but does not appear until midlife.  Recessive gene disorders, such as cystic fibrosis and sickel-cell anemia, are less common but may actually claim more lives because they are less likely to be detected as people are unaware that they are carriers of the disease. If the genes inherited from each parent are the same, the child is homozygous for a particular trait and will inherit the trait. If, however, the child inherits a gene from one parent but not the other, the child is heterozygous, and interaction between the genes will in part determine whether or not that trait is expressed (Berk, 2004).

REFERENCES

  1. Berger, K. S. (2005). The developing person through the life span (6th ed.). New York: Worth.
  2. Berk, L. (2004). Development through the life span (3rd ed.). Boston: Allyn and Bacon.
  3. Bortolus, R., Parazzini, F., Chatenoud, L., Benzi, G., Bianchi, M. M., & Marini, A. (1999). The epidemiology of multiple births. Human Reproduction Update, 5, 179-187.
  4. Brazelton, T. B., & Nugent, J. K. (1995). Neonatal behavioral assessment scale. London: Mac Keith Press.
  5. Carrell, D. T., Wilcox, A. L., Lowry, L., Peterson, C. M., Jones, K. P., & Erikson, L. (2003). Elevated sperm chromosome aneuploidy and apoptosis in patients with unexplained recurrent pregnancy loss. Obstetrics and Gynecology, 101(6), 1229-1235.
  6. Carroll, J. L. (2007). Sexuality now: Embracing diversity (2nd ed.). Belmont, CA: Thomson.
  7. Dietrich, K. N. (1999). Environmental toxicants and child development. In Tager-Flusberg (Ed.), Neurodevelopmental disorders (pp. 469-490). Boston: MIT Press.
  8. FASD, NCBDDD, CDC. (2006, July/August). Centers for Disease Control and Prevention. Retrieved May 03, 2011, from http://www.cdc.gov/ncbddd/fas/fasask.htm
  9. Galinsky, E. (1987). The six stages of parenthood. Reading, MA: Addison-Wesley Pub.
  10. Gottlieb, G. (1998). Normally occurring environmental and behavioral influences on gene activity: From central dogma to probabilistic epigenesis. Psychological Review, 105, 792-802.
  11. Gottlieb, G. (2000). Environmental and behavioral influences on gene activity. Current Directions in Psychological Science, 9, 93-97.
  12. Gottlieb, G. (2002). Individual development and evolution: The genesis of novel behavior. New York: Oxford University Press.
  13. Gould, J. L. (1997). Biological science. New York: Norton.
  14. Lippa, R. A. (2002). Gender, nature, and nurture. Mahwah, NJ: L. Erlbaum.
  15. MacDorman, M., Menacker, F., & Declercq, E. (2010, August 30). Trends and Characteristics of Home and Other out of Hospital Births in the United States, 1990-2006 (United States, Center for Disease Control). Retrieved December 22, 2010, from http://www.cdc.gov/nchs/data/nvsr/nv...;nvsr58_11.PDF
  16. Mackon, N., & Fauser, B. (2000). Aspects of ovarian follicle development throughout life. Hormone Research, 52, 161-170.
  17. McKusick, V. A. (1998). Mendelian inheritance in man: A catalog of human genes and genetic disorders. Baltimore, MD: Johns Hopkins University Press.
  18. Moore, K. L., & Persaud, T. V. (1998). Before we are born (5th ed.). Philadelphia, PA: Saunders.
  19. Mutti, D. O., Zadnik, K., & Adams, A. J. (n.d.). Myopia. The nature versus nurture debate goes on. Investigative Ophthalmology & Visual Science. Retrieved May 03, 2011, from http://www.iovs.org/cgi/reprint/37/6/952
  20. Newell, M. (2005). Current issues in the prevention of mother-to-child transmission of HIV-1 infection. Transactions of the Royal Society of Tropical Medicine and Hygiene, 100(1), 1-5. doi: 10.1016/j.trstmh.2005.05.012
  21. Rome, E. (1998). Anatomy and physiology of sexuality and reproduction. In The New Our Bodies, Ourselves (pp. 241-258). Carmichael, CA: Touchstone Books.
  22. UNAIDS, World Health Organization. (2005). Adults and Children Estimated to Be Living with HIV as of the End of 2005. Retrieved August 13, 2006, from http://www.unaids.org?NetTools/Misc/...x?LANG=en&href http://GVA-DOC-OWL/WEBcontent/Docume...lide004_en.ppt
  23. United States, Center for Disease Control. (n.d.). The Health Consequences of Smoking: 2004 Report of the Surgeon General. Retrieved August 14, 2004, from http://www.cdc.gov/tobacco/sqr/sqr_2004
  24. United States, Center for Disease Control. (2006, July/August). Sexually Transmitted Diseases Treatment Guidelines. Retrieved August 14, 2006, from http://www.cdc.gov/std/treatment/2006/rr5511.pdf
  25. United States, Center for Disease Control, Health and Human Services. (2010, October 5). Centers for Disease Control and Prevention. Retrieved May 03, 2011, from http://www.cdc.gov/nchs/faststats/birthwt.htm
  26. United States, Center for Disease Control, National Center on Birth Defects and Developmental Disabilities. (2004, October 29). Fast Facts about Medication Use during Pregnancy and While Breastfeeding. Retrieved August 10, 2006, from http://www.cdc.gov/ncbddd/fas/fasask.htm
  27. World Health Organization. (2010, September 15). Maternal Deaths Worldwide Drop by a Third, WHO. Retrieved December 22, 2010, from http://www.who.int/mediacentre/news/.../en/index.html