FACTOID # 27: If you're itching to live in a trailer park, hitch up your home and head to South Carolina, where a whopping 18% of residences are mobile homes.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
   
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > 47,XYY syndrome

XYY, or "XYY syndrome," is a trisomy of the sex chromosomes in which a human male receives an extra Y chromosome in each cell, hence having a karyotype of 47,XYY.

Contents

Effects

Physical traits

XYY syndrome typically causes no unusual physical features or medical problems. Persons with this syndrome may be slightly taller than average, or have more severe acne than normal. Skeletal malformations may also accompany XYY syndrome at a higher rate than in the general population. Several other physical characteristics, including large hands and feet, have been associated (although not definitively) with XYY syndrome. Any physical characteristics, however, are usually so slight that they are insufficient evidence to suggest a diagnosis.


Most males with XYY syndrome have normal sexual development and are able to conceive children.


Since there are no distinct physical characteristics, the condition usually is only detected during genetic analysis for other reasons.


Behavioral characteristics

There are reports that men with XYY syndrome may be more likely to have behavior problems, possibly due to a higher testosterone level, but these are usually avoided if the syndrome is detected early. There are also reports of learning disabilities and delayed speech and language skills, but they may be caused by the behavior problems.


An earlier study suggested that XYY males were more likely to be incarcerated and be criminal, but the study is now widely considered as procedurally flawed. The misleading data resulted from the study being carried out in prisons (a classic self-selection error).


Researchers are not yet certain why an extra copy of the Y chromosome should be associated with tall stature and learning problems.


Cause and prevalence

XYY syndrome is not inherited, but usually occurs as a random event during the formation of sperm cells. An error in cell division called nondisjunction can result in sperm cells with an extra copy of the Y chromosome. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra Y chromosome in each of the body's cells. In some cases, the addition of an extra Y chromosome occurs as an accident during cell division in early fetal development.


The incidence of this condition is about one in 850 males.


Reference

  • public domain text from the NLM Genetics Home Reference at [1] (http://ghr.nlm.nih.gov/condition=47xyysyndrome).



  Results from FactBites:
 
XYY Syndrome / Jacob's Syndrome for Lesson Plans & Science Fair Projects (571 words)
XYY syndrome is a aneuploidy of the sex chromosomes in which a human male receives an extra Y chromosome in each cell, hence having a karyotype of 47,XYY.
Males with this syndrome may be slightly taller than average and are typically a few centimeters taller than their father and siblings.
XYY syndrome is not inherited, but usually occurs as a random event during the formation of sperm cells.
47,XYY syndrome - Genetics Home Reference (626 words)
Males with 47,XYY syndrome are sometimes taller than average and have an increased risk of learning disabilities and delayed speech and language skills.
47,XYY syndrome is a chromosomal condition related to the Y chromosome.
47,XYY syndrome is caused by the presence of an extra copy of the Y chromosome in each of a male's cells.
  More results at FactBites »

 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m