Question

A boy with Klinefelter syndrome (47,XXY) is born to a mother who is phenotypically normal and a father who has the X-linked skin condition called anhidrotic ectodermal dysplasia. The mother’s skin is completely normal with no signs of the skin abnormality. In contrast, her son has patches of normal skin and patches of abnormal skin. Which parent contributed the abnormal gamete, when did the meiotic mistake occur, and explain the son’s skin phenotype.

Answer 1

The skin disease suggests that the father contributed with the extra X chromosome. It means, the nondisjunction ocurred during the sperm formation, giving as a product of meiosis II probably two normal sperm, one with 22 chromosomes and one with 24 chromosomes (the extra X).

Step-by-step explanation: