Older Age of the Parent Who Donated the Extra X Chromosome is a Risk Factor For Klinefelter's Syndrome

At least one of the X chromosomes must have come from the mother and the Y chromosome must have come from the father. However, the additional X chromosome may originate from either parent. A maternal origin for the extra X is slightly more common2. Older age of the parent who donated the additional chromosome is a risk factor for Kinefelter's syndrome3.
Klinefelter's Syndrome, a sex-linked disorder << back
3 Jul 2007
Paul Hewish, general practitioner and author, Norfolk. Reviewed by Louise Newson, general practitioner, Birmingham
Klinefelter's syndrome is XXY karyotype but there may be variations and mosaics.
Presentation is often not until puberty when they develop gynaecomastia and fail to develop sexually. Testes are small was absent sperm production.
They are tall and thin.
Testosterone therapy will aid sexual maturation, muscle development and prevent fatigue and osteoporosis but there is infertility.
There is increased risk of malignancies including those of testicular origin and breast cancer.
Intelligence is slightly below normal.
Life expectancy is normal....................