Re: Is an 'XXY' male less likely than an 'XY' male to have sex linked disorders

Dear Barbara, 
That is a really interesting question.  I'm not an expert on these 
disorders but I have given a lecture on the subject and found in my 
research that people with XXY are more prone to having typically 'female' 
diseases such as osteoperosis and breast cancer.  That doesn't answer your 
question though.  Some XXY males are a mosaic of tissues with some being XY 
and some being XXY and this could effect the concentration of X chromosome 
protien products in areas with only XY - perhaps this could lead to 
localised normal susceptibility to X-linked disorders or protection from 
in XXY areas but this is just my own speculation.

Females are XX but X inactivation doesn't stop them from having less chance 
of getting X-linked disorders so presumable XXY males would also benefit 
from the extra X chromosome in this way.  I've read that very few studies 
have been performed on adult XXY males so perhaps the answer just isn't out 
there yet or it may be that it is difficult to distinguish between symptoms 
due to the XXY phenotype (e.g. some have mental retardation)and symptoms 
which would be due to X-linked disorders.

If you want further information then a good site is  http://www.nih.gov/health/chip/nichd/klinefelter/#xhealth

My advice would be go search the websites dedicated to this disorder and 
contact the person who made the best site.


Yvonne