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X&Y Chromosome Variations: Overview

What are X&Y chromosome variations?

X & Y Chromosome variations

X&Y chromosome variations refer to conditions in which a child has an abnormal number of sex chromosomes, also known as X&Y chromosomes.

Other words used to describe X&Y chromosome variations are “sex chromosome anomaly,” “sex chromosome abnormality” and “sex chromosome aneuploidy.”

How do X&Y chromosome variations affect boys and girls?

Males usually have one X and one Y chromosome, and females usually have two X chromosomes. Occasionally, because of problems with the formation of a parent’s sperm or egg, a child can be born with extra or too few sex chromosomes.

For reasons we don’t completely understand, children with X&Y chromosome variation can also have developmental delays, intellectual disability and autism spectrum disorders. Boys with extra X chromosomes need to be seen by an endocrinologist during puberty to help balance their testosterone levels.  

Specific forms of sex chromosome variations include:

X&Y chromosome variations in males X chromosome variations in females
47,XXY  (Klinefelter syndrome) 45,X (Turner syndrome)
47,XYY 47,XXX (Trisomy X or Triple X)
48,XXYY 48,XXXX (Tetrasomy X)
48,XXXY 49,XXXXX (Pentasomy X)
49,XXXXY --

What causes sex chromosome variations? 

Children are born with X&Y chromosome variations. These conditions are caused by a problem in the division of the X and Y chromosomes during the formation of a parent’s egg or the sperm, which are then involved in conception. The exact cause is unknown, and these conditions are typically not inherited.

Helpful resources:

For more information or to make an appointment at the eXtraordinarY Kids Clinic, please call 720-777-8361 or send us an email.